

August 2020

Prepared for:

Department of Veterans Affairs

Veterans Health Administration

Health Services Research & Development 

Service

Washington, DC 20420

Prepared by:

Evidence Synthesis Program (ESP) 

Coordinating Center

Portland VA Health Care System

Portland, OR

Mark Helfand, MD, MPH, MS, Director 

Evidence Brief:

Virtual Diet Programs 

for Diabetes 

Authors: 

Stephanie Veazie, MPH

Kathryn Vela, MLIS

Mark Helfand, MD MPH

Evidence Synthesis Program
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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PREFACE

The VA Evidence Synthesis Program (ESP) was established in 2007 to provide timely and 

accurate syntheses of targeted healthcare topics of importance to clinicians, managers, and 

policymakers as they work to improve the health and healthcare of Veterans. These reports help: 

• Develop clinical policies informed by evidence;

• Implement effective services to improve patient outcomes and to support VA clinical 

practice guidelines and performance measures; and 

• Set the direction for future research to address gaps in clinical knowledge.

The program is comprised of three ESP Centers across the US and a Coordinating Center located 

in Portland, Oregon. Center Directors are VA clinicians and recognized leaders in the field of 

evidence synthesis with close ties to the AHRQ Evidence-based Practice Center Program and 

Cochrane Collaboration. The Coordinating Center was created to manage program operations, 

ensure methodological consistency and quality of products, and interface with stakeholders. To 

ensure responsiveness to the needs of decision-makers, the program is governed by a Steering 

Committee comprised of health system leadership and researchers. The program solicits 

nominations for review topics several times a year via the program website. 

Comments on this evidence report are welcome and can be sent to Nicole Floyd, Deputy 

Director, ESP Coordinating Center at Nicole.Floyd@va.gov.

Recommended citation: Veazie S, Vela K, Helfand M. Evidence Brief: Virtual Diet Programs 

for Diabetes. VA ESP Project #09-199; 2020. Posted final reports are located on the ESP 

search page.

This report is based on research conducted by the Evidence Synthesis Program (ESP) Coordinating Center 

located at the Portland VA Health Care System, Portland, OR, funded by the Department of Veterans 

Affairs, Veterans Health Administration, Health Services Research and Development. The findings and 

conclusions in this document are those of the authors who are responsible for its contents; the findings and 

conclusions do not necessarily represent the views of the Department of Veterans Affairs or the United 

States government. Therefore, no statement in this article should be construed as an official position of the 

Department of Veterans Affairs. No investigators have any affiliations or financial involvement (eg, 

employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents 

received or pending, or royalties) that conflict with material presented in the report.
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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TABLE OF CONTENTS

Executive Summary........................................................................................................................ 1

Key Findings ................................................................................................................................ 1

Introduction ..................................................................................................................................... 6

Purpose ............................................................................................................................................ 6

Background ..................................................................................................................................... 6

Scope ............................................................................................................................................... 8

Key questions .................................................................................................................................. 8

Eligibility criteria ............................................................................................................................ 9

Methods......................................................................................................................................... 10

Searches and Study Selection ....................................................................................................... 10

Quality Assessment & Data Extraction ........................................................................................ 10

Strength of Evidence Assessment ................................................................................................. 10

Synthesis of Data .......................................................................................................................... 10

Results ........................................................................................................................................... 12

Literature Flow .............................................................................................................................. 13

Part I: Programs Promoting a Named Diet ................................................................................... 16

Overview .................................................................................................................................... 16

TeLiPro (Meal Replacement Diet) ............................................................................................. 17

Virta Health (Ketogenic Diet) .................................................................................................... 17

Low Carb Program (Low Carbohydrate Diet) ........................................................................... 19

Better Therapeutics (Plant-based Diet) ...................................................................................... 20

Part 2: Programs that Promote Healthy Eating Based on Guidelines ........................................... 21

u-Healthcare (US & South Korea Guidelines)........................................................................... 22

ANODE (France Guidelines) ..................................................................................................... 23

Our Path (UK. Guidelines) ........................................................................................................ 24

GlycoLeap (US and Singapore Guidelines) ............................................................................... 24

Part 3: Programs that Promote Healthy Eating Not Based on Named Diet or Guideline ............. 25

Overview .................................................................................................................................... 25

My Dietitian ............................................................................................................................... 26

Noom Coach .............................................................................................................................. 27

Unnamed Programs .................................................................................................................... 28

DiabMemory + Nutrinaut .......................................................................................................... 28

Summary and Discussion .............................................................................................................. 30
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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Limitations .................................................................................................................................... 31

Gaps and Future Research ............................................................................................................ 32

Conclusions ................................................................................................................................... 34

Acknowledgments......................................................................................................................... 35

Operational Partners ................................................................................................................... 35

Key Informants .......................................................................................................................... 35

References ..................................................................................................................................... 36

FIGURES AND TABLES 

Table 1. Summary of Findings ........................................................................................................ 3

Figure 1: Literature Flowchart ...................................................................................................... 13

Table 3. Overview of Studies on Virtual Diabetes Diet Programs ............................................... 14

Table 4. Detailed Findings from Studies of Named Diet Programs ............................................ 16

Table 5. Detailed Findings From Studies of Programs That Promote Healthy Eating Based on 

Guidelines ..................................................................................................................................... 21

Table 6. Detailed Findings From Studies of Programs That Promote Healthy Eating not Based on 

Diabetes or Dietary Guidelines ..................................................................................................... 25
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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EXECUTIVE SUMMARY

Key Findings

• 15 studies (9 RCTs, 1 non-randomized controlled trial, 3 

single-arm longitudinal studies, and 2 pre-post studies) 

evaluated 14 virtual diabetes diet programs with a coaching 

component. 

• In a single study that was poorly controlled, selected 

participants (ie, those who were severely obese, interested 

in an intensive diabetes management program, and willing 

to adhere to the ketogenic diet) experienced improvements 

in weight and HbA1c after participating in the Virta Health

program for 10 weeks and maintained improvements if 

they continued to participate in the program for 2 years. 

Some of these participants also stopped taking medications 

and reversed their diabetes.

• In 1 RCT, 1 longitudinal study, and 1 before-after study, 

participants in 3 other programs (TeLiPro, Low Carb 

Program, and Better Therapeutics) experienced 

improvements in 2 diabetes-related outcomes (ie, lowering 

HbA1c > .5%, weight loss > 5%, and/or diabetes 

medication cessation) between 3 months to 1 year after 

program initiation. In 5 RCTs, 1 longitudinal study and 1 

before-after study, participants in 6 other programs (uHealthcare, Our Path, GlycoLeap, Noom Coach, and 2 

unnamed programs) experienced improvements in 1 

diabetes-related outcome (either lowering HbA1c or weight 

loss) between 3 and 6 months after program initiation. 

Those who participated in Noom Coach also had higher 

rates of diabetes reversal than controls. 

• Data on harms were sparse. Only studies of Virta Health, 

Better Therapeutics, and Noom Coach reported that no 

severe or serious treatment-related harms occurred. 

• As health systems like the VA begin to implement virtual 

diabetes coaching programs, evaluations should emphasize 

creation of appropriate control arms; ensuring comparable 

long-term follow-up data; and attention to possible harms. 

Since evidence isn’t clear which features of programs are 

most critical, a health system might also wish to compare 

virtual programs delivering different types of diets.

Background

The ESP Coordinating 

Center (ESP CC) is 

responding to a request 

for a rapid review on 

virtual diet programs for 

diabetes from the VA 

Health Services Research 

& Development 

(HSR&D). Findings 

from this evidence brief 

will be used to inform an 

evaluation of the Virta 

Health program among 

Veterans with type 2 

diabetes. 

Methods 

To identify studies, we 

searched MEDLINE, 

CINAHL and Cochrane 

Central Register of 

Controlled Trials 

(CENTRAL). We used 

prespecified criteria for 

study selection, data 

abstraction, and rating 

internal validity and 

strength of the evidence. 

See our PROSPERO 

protocol for our full 

methods (Registration # 

CRD 42020180278).
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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In recent years, the ketogenic diet has become an increasingly popular option for people looking 

to lose weight, including those with type 2 diabetes. The ketogenic diet is a low carbohydrate, 

high fat diet, where approximately 70% of an individual’s calories come from fat, 20% from 

protein, and 10% or less from carbohydrates. Proponents of the diet point to studies indicating it 

can help with weight loss, improve cholesterol and blood pressure, reduce the need for 

medications, and potentially reverse diabetes, while skeptics have pointed out there are no longterm (>1 year) studies on the ketogenic diet, so it is unclear whether these benefits are 

maintained over time and if there are any long-term risks. 

Virta Health is an online platform that delivers a ketogenic diet intervention – as well as 

education, coaching and physician management of medications – for people with type 2 diabetes. 

In 2019, Virta Health and the VA initiated a pilot project in which 400 Veterans with type 2 

diabetes were given access to the Virta Health program. On its website, Virta claims that 84% of 

Veteran patients on the Virta treatment for 90 days achieved glycemic outcomes below the 

diabetes threshold or at least a 1-point drop in HbA1c (a measure of blood sugar). No data from 

Virta’s VA pilot project have been published, so this claim cannot be verified. A separate, singlecenter, open-label, nonrandomized controlled study that provides the only evidence about the 

Virta program indicates that program participants can lose weight, lower HbA1c, discontinue 

medications, and reverse diabetes. This study, which is expected to be completed in 2021, has 

important limitations, and it is unclear how this program compares to other programs that deliver 

similarly comprehensive, continuous remote care. If properly designed, the VA’s ongoing 

evaluation of the Virta VA pilot could address important gaps in the evidence about Virta. 

Virta’s ongoing evaluation might also close some gaps. Furthermore, the VA is contemplating 

expanding virtual diet programs and will need to design a prospective evaluation to assess the 

impact of whatever program is selected. 

We conducted a rapid evidence review assessing the last 5 years of research on the Virta Health 

program and other similar programs, focusing on weight loss, HbA1c, and medication reduction, 

the outcomes that have been emphasized by Virta and proponents of other virtual programs. We 

also focused on harms. In addition to the study of Virta, we identified 9 RCTs, 3 single-arm 

longitudinal studies, and 2 pre-post studies of 13 other virtual diabetes diet programs (Table 1). 

Studies examined 3 types of programs: 

1. Programs that promote a named diet (ie, one where certain categories of food or 

macronutrients are limited, such as the ketogenic diet, low carbohydrate diet, or plantbased diet).

2. Programs that promote healthy eating based on a diabetes or dietary guideline.

3. Programs that promote healthy eating not based on a named diet or guideline.

Overall, although the study of Virta had important limitations, it suggests that for some patients

(ie, those who are severely obese, interested in an intensive diabetes management program, and 

willing to adhere to the ketogenic diet), participation in Virta Health is associated with

improvements in diabetes outcomes such as weight and HbA1c at 10 weeks. Some participants 

of the program also stopped taking medications and reversed their diabetes. These outcomes 

were maintained for up to 2 years in patients who continue to participate in the intervention. 

Three other virtual diet programs for diabetes (TeLiPro, Low Carb Program, and Better 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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Therapeutics), all of which delivered a named diet, were associated with a clinically significant 

improvement in 2 diabetes outcomes (ie, lowering HbA1c >.5%, weight loss > 5%, and/or 

diabetes medication cessation) between 3 months and 1 year after initiation. Participants in 2 of 

these programs (TeLiPro and Low Carb Program) maintained improvements for 1 year (in 1 

program the intervention ended at 12 weeks, and in the other the intervention continued for a 

year). Although benefits were more limited, 6 additional virtual diet programs (u-Healthcare, 

Our Path, GlycoLeap, Noom Coach, and unnamed programs from Wayne 2015 and Sun 2019) 

were associated with a clinically meaningful improvement in 1 diabetes-related outcome (either 

lowering HbA1c > .5% or weight loss > 5%) between 3 and 6 months after initiation. In the 

Noom Coach study, more people reversed diabetes in the intervention group than the control 

group. Few studies reported on harms, but of those that did (Virta Health, Better Therapeutics, 

and Noom Coach), none found serious or severe treatment-related harms.

Table 1. Summary of Findings

Intervention 

category 

Supporting 

evidence

Total N

Virtual diet 

programs 

Changes 

in weight*

Changes 

in HbA1c* 

Changes in 

medication 

use* 

Harms Strength of 

evidence (SOE) & 

limitations

Programs 

promoting a 

named diet 

4 studies 

(1 RCT, 1 nonrandomized 

controlled trial, 

1 single-arm 

longitudinal, 1 

pre-post) 

N = 1,669

• TeLiPro

• Virta Health 

• Low Carb 

Program 

• Better 

Therapeutics 

↓3-12%

(3 studies) 

↓.8%-1.4% 

(4 studies)

9-40% of 

those taking 

diabetes 

medications 

at baseline 

stopped 

taking them

(3 studies). 

No serious 

treatmentrelated harms 

of Virta Health

or Better 

Therapeutics

(2 studies). 

Low SOE

• Each program 

only evaluated in 

1 study. 

• 2 studies were 

uncontrolled

• 1 controlled study 

had unequal 

groups at 

baseline and 

other important 

limitations

including high 

attrition

Programs 

promoting 

healthy eating 

based on 

guidelines 

5 studies 

(3 RCTs, 1 

single-arm 

longitudinal, 1 

pre-post)

N = 1,268

• u-Healthcare

• ANODE

• Our Path

• GlycoLeap

↓2.5-8%

(4 studies)

↓.4-1.1%

(3 studies)

12% of ppts 

in uHealthcare 

intervention 

reduced 

dosage of 

oral 

antidiabetic 

drugs or 

insulin

(1 study). 

NR Low SOE

• Each program 

only evaluated in 

1 study (except 

u-Healthcare)

• 2 studies were 

uncontrolled

• High attrition and

differential 

attrition between 

groups 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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Intervention 

category 

Supporting 

evidence

Total N

Virtual diet 

programs 

Changes 

in weight*

Changes 

in HbA1c* 

Changes in 

medication 

use* 

Harms Strength of 

evidence (SOE) & 

limitations

Programs 

promoting 

healthy eating 

not based 

named diet or 

guidelines 

6 studies

(5 RCTs and 1 

pre-post study)

N = 462

• My Dietitian

• Noom Coach

• Diab Memory 

+ Nutrinaut

• 3 unnamed 

programs

↓1-4% 

(2 studies)

↓.4-1.9% 

(4 studies)

15% reduced 

dosage of 

oral diabetes 

medication or 

insulin 

(1 study). 

No severe 

hypoglycemia 

or 

hospitalization 

occurred 

during Noom 

Care 

intervention (1 

study). 

Low SOE

• Each program 

only evaluated in 

1 study

• Studies were 

small

• High attrition

*Represents changes in outcomes experienced among intervention group participants from baseline to follow-up.

↓=decrease; ↑=increase; NR=Not reported; ppts = participants

Italics= Meets criteria for a minimum clinically important difference (ie, weight loss ≥ 5%, HbA1c reduction ≥ .5%, 

stopping any or all diabetes medications, no severe treatment-related harms) 

There were limitations to our rapid review methods as well as limitations of the primary studies. 

One limitation is that we did not include studies older than 5 years. An additional limitation is 

that we had a single reviewer include studies and abstract data with second reviewer checking, 

which could have resulted in missing eligible studies or data. However, we made attempts to 

reduce this risk by establishing explicit inclusion criteria for studies and developing and using a 

piloted data abstraction tool. 

In terms of primary study limitations, one-third (5/15) did not include a separate control group, 

and among those that did use a control group, half (5/10) used a control group that was not 

similar to the intervention group in terms of intensity. This made it impossible to determine what 

caused the differences in outcomes (ie, the diet, the coaching, the access to virtual tools to track 

outcomes, the frequent interactions with health care providers or coaches, or a combination of 

these components). 

Our primary recommendations for the VA’s retrospective evaluation of the initial group of 

Veterans enrolled in the Virta Health pilot project is to collect detailed information on 

participants’ baseline characteristics (including BMI, HbA1c, lipid levels, duration of diabetes, 

and any comorbidities) and measure the same outcomes (weight, HbA1c, and diabetes 

medication cessation) at the same time points (3 months, 1 year, and 2 years) as the Virta study. 

We also recommend researchers use intent-to-treat analysis to assess the effectiveness of Virta 

among all participants who enrolled, and to consider stratifying by engagement in the program to 

determine the minimum level of engagement needed for a clinically meaningful change in 

outcomes. 

Our primary recommendation for the prospective evaluation of Veterans that may enroll in an 

expanded virtual diet program in the future is to compare that program to a similarly intensive 

intervention, either a different commercial program based on a different dietary approach or one 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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delivered by VA staff (such as virtual health coaches). For both parts of the evaluation, we 

recommend that researchers capture a wide range of information on harms, including 

exacerbation or development of conditions such as diverticulitis. 

By using a suitable comparator, we believe the VA evaluation could help determine whether the 

benefits of the virtual diet program are dependent primarily on the specific diet or on the remote 

continuous care intervention and coaching support. As Veterans’ preferences for the type of diet 

they follow are likely to vary, a practical solution to improving diabetes care should include a 

variety of diet options if the particular diet is not the critical component of the intervention. This 

comparison could also inform how virtual diabetes programs might be adapted to meet the needs 

of a variety of Veterans with type 2 diabetes.
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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EVIDENCE BRIEF

INTRODUCTION

PURPOSE

The ESP Coordinating Center (ESP CC) is responding to a request from the Department of 

Veterans Affairs (VA) Health Services Research & Development (HSR&D) program for an 

evidence brief on the effectiveness and harms of Virta Health and other virtual diet programs 

which include a coaching component for type 2 diabetes. The VA is planning to evaluate the 

effect of Virta Health among Veterans, and findings from this review could help inform power 

estimations, possible comparators and outcomes, and length of follow-up, among other study 

features.

BACKGROUND

One in 4 Veterans has some form of diabetes, which is twice the rate seen in the general US

population.1,2 Type 2 diabetes, characterized by insulin resistance that can result in deficiencies 

in insulin secretion, is the most common form of diabetes and is thought to be primarily caused 

by excess weight in the body.3 When untreated, type 2 diabetes can lead to microvascular 

complications including retinopathy (damage to the eyes that can result in blindness), 

nephropathy (damage to the kidneys that can result in kidney failure), and neuropathy (damage 

to the nerves in hands and feet that can result in amputation), as well as macrovascular 

complications including increased risk of heart disease, stroke, and coronary events such as heart 

attacks. Treatment of type 2 diabetes includes the self-management of lifestyle factors (eg, diet, 

exercise) to reduce or maintain weight, tracking of biomarkers (eg, blood glucose levels) that can 

indicate diabetes is worsening or uncontrolled, use of medications (eg, metformin, insulin) that 

augment insulin levels, increase sensitivity to insulin, or impart other glucose-lowering effects,

and monitoring and treating diabetes-related complications.

While there is widespread consensus that maintaining a healthy diet is a key part of diabetes 

management, there is no consensus on the ideal diet for diabetes. Guideline groups including the 

Department of Veterans Affairs/Department of Defense (VA/DOD), American Diabetes 

Association (ADA), and the Academy of Nutrition and Dietetics (the Academy) all recommend 

people with diabetes receive medical nutrition therapy (MNT) consisting of a nutrition 

assessment, diagnosis, intervention (including education and counseling), and 

monitoring/evaluation. However, they disagree on whether patients receiving MNT should 

follow a particular diet. The VA/DOD recommends that the Mediterranean diet (high intake of 

vegetables, fruits, nuts, unrefined grains, and olive oil; moderate intake of fish and poultry; low 

or moderate intake of wine; and low intake of red meat, processed meat, dairy, and sweets) be

offered first to patients, then a low carbohydrate (14-45% of total calories) and/or low glycemic 

index diet be offered second if patients don’t choose the Mediterranean diet.3 These 

recommendations emphasize that the chosen diet be tailored to patient preferences and needs. By 

contrast, both the Academy and ADA recommendations state that a variety of diets are 

acceptable for the management of diabetes, with the Academy emphasizing that personal 

preferences be considered and the ADA suggesting that clinicians focus on the common 

elements among diets for diabetes including emphasis of non-starchy vegetables, minimizing 

added sugars and refined grains, and choosing whole foods over highly processed foods.

4,5
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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In recent years, the ketogenic diet has become an increasingly popular option for people looking 

to lose weight, including those with type 2 diabetes.6 The ketogenic diet is a low carbohydrate, 

high fat diet, where approximately 70% of an individual’s calories come from fat, 20% from 

protein, and 10% or less from carbohydrates.7 The ketogenic diet is distinct from other types of 

low carbohydrate diets (eg, Atkins, Paleo, and South Beach) as the majority of calories come 

from fat, rather than protein. The ketogenic diet dates back to the early 1900s when it was 

developed and used as a treatment for diabetes prior to the invention of insulin.

8 Diets similar to 

ketogenic such as the very low carbohydrate diet are currently recommended by groups such as 

the National Institute for Health and Care Excellence (NICE) for instances in which patients 

need to lose weight rapidly, such as prior to joint replacement surgery or fertility treatments.9

The theory underlying the ketogenic diet is that restricting carbohydrates limits the body’s access 

to glucose (the body’s main source of energy) and forces it to burn stored fat (called ketones)

instead.7 The process of burning ketones is called ketosis, and has been linked to a number of 

metabolic benefits.

10 Proponents of the ketogenic diet cite studies indicating it can lead to weight 

loss, improve cholesterol and blood pressure, reduce the need for medications and reverse 

diabetes.11,12 There have also been anecdotal accounts that the ketogenic diet is easier to follow

than other types of restrictive diets, since high fat foods such as fatty cuts of meat, eggs, and 

butter are allowed and there are no restrictions on the amount of calories consumed. However, 

skeptics have pointed out there are no long-term (> 1 year) studies of the effect of the ketogenic 

diet, so it is unclear whether these benefits are maintained over time, and if there are any longterm risks to patients with diabetes such as worsening of cardiovascular disease risk factors 

including LDL cholesterol, hypoglycemia (drop in blood glucose that can cause patients to pass 

out) or ketoacidosis (harmful levels of ketones in the blood that can cause diabetic coma or 

death).13,14

A 2019 rapid response (review of reviews)15 by the Canadian Agency for Drugs and 

Technologies in Health (CADTH) provides the most recent and rigorous assessment of the 

effectiveness and harms of low carbohydrate diets (including the ketogenic diet) compared to 

control diets (no or minimal intervention) for diabetes. Due to the mixed findings of included 

systematic reviews, the report does not provide a definitive answer on the effectiveness and 

harms of these diets. The report looked at 10 systematic reviews published from January 2016 to 

October 2019. Because there were no primary studies that compared low carbohydrate diets to 

control diets, the most direct evidence comes from 3 network meta-analyses (NMA) conducted 

in 3 reviews. One NMA16 of 52 RCTs (duration 3-48 months) found that low carbohydrate diets 

were not significantly more effective than control diets at improving LDL cholesterol or HDL 

cholesterol, but were more effective at improving triglycerides (moderate strength of evidence). 

A second NMA17 of 10 trials (duration not reported) found that low carbohydrate diets were not

significantly more effective than control diets at improving HbA1c, total cholesterol, HDL 

cholesterol, triglycerides, or BMI (strength of evidence not reported). A third NMA18 of 56 

RCTs (duration 3-48 months) found that low carbohydrate diets were significantly more 

effective than control diets at improving HBA1c and fasting glucose (low strength of evidence). 

Given the conflicting evidence on the ideal diet for improving outcomes for patients with type 2 

diabetes, researchers continue to evaluate the effects of different diets on patient outcomes. In 

recent years, researchers, clinicians, and patients have become increasingly interested in using 

virtual tools such as apps, websites, and online patient portals as an alternative or additional 

modality for supporting diabetes self-management.19-21 Using virtual tools has the potential to 

increase patients’ access to these interventions (as they can log into a virtual class or otherwise 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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access content at home rather than traveling to a clinic), adherence (since these types of 

interventions can be more easily adapted to patients’ schedules, needs, and preferences than inperson interventions), as well as satisfaction with care. Virtual tools can also help patients with 

the burdensome process of tracking information related to their health, such as diet, physical 

activity, and biometrics like HbA1c, and provide additional avenues for communication and 

support, such as through texting with a dietitian or joining a group forum of other patients.

One such virtual program is Virta Health, an online platform that delivers a suite of services 

related to diabetes management, including nutrition and behavioral counseling focused on the 

ketogenic diet, as well as education, coaching, and physician management of medications (ie, 

titration of medications based on biomarker tracking).

22 Virta Health’s website states that it is a 

“proven treatment to reverse type 2 diabetes” and provides links to its peer-reviewed papers. In 

May 2019, the Department of Veterans Affairs (VA) initiated a pilot project in which 400 

Veterans were given access to the Virta Health program with the goal of improving their 

diabetes-related outcomes. In November 2019, Virta Health stated on its website that of the first 

104 patients enrolled in the pilot project, 84% had either a 1-point drop in HbA1c or had a drop 

below the clinical threshold for diabetes within 90 days, and 53% experienced a reduction in 

prescriptions for diabetes-specific medications.23 No data from Virta’s VA pilot project have 

been published, so this claim cannot be verified. A separate, single-center, open-label, 

nonrandomized controlled study provides the only evidence about the Virta program and

indicates that program participants can lose weight, lower HbA1c, discontinue medications, and 

reverse diabetes.11 This study, which is expected to be completed in 2021, has important 

limitations, and it is unclear how this program compares to other programs that deliver 

comprehensive, continuous remote care. If properly designed, the VA’s ongoing evaluation of 

the Virta VA pilot project could address important gaps in the evidence about Virta. Virta’s 

ongoing study might also close some gaps. The VA is also contemplating expanding virtual diet 

programs and will need to design a prospective evaluation to assess the impact of whatever 

program is selected. 

This rapid evidence review was commissioned by the VA’s Health Services Research & 

Development (HSR&D) program to help inform an evaluation of the Virta Health program 

among Veterans. The primary goal of this review is to assess the effectiveness and harms of all 

available virtual diabetes diet programs that include a coaching program on the three outcomes 

(weight loss, HbA1c, and medication reductions) that have been emphasized by Virta and 

proponents of other virtual programs. A secondary goal is to identify gaps in knowledge that 

could be informed by future research. 

SCOPE

This rapid evidence review assesses the effectiveness and harms of virtual diabetes diet programs 

which include a coaching component among patients with type 2 diabetes.

KEY QUESTIONS

Key Question 1: Among adults with type 2 diabetes, what is the effectiveness of virtual diabetes 

diet programs which include a coaching component?

Key Question 2: Among adults with type 2 diabetes, what are the harms of virtual diabetes diet 

programs which include a coaching component?
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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ELIGIBILITY CRITERIA

The ESP included studies that met the following criteria:

• Population: Adults with type 2 diabetes

• Intervention: Diabetes diet program (eg, ketosis, low carb, etc) with coaching component 

(eg, patient provides diabetes-related information and receives personalized feedback 

from a provider or algorithm) delivered virtually. We considered a diet program to be one 

that delivers education or counseling related to diet. 

• Comparator: Any, including no comparator

• Outcomes:

o Benefits: Weight loss, HbA1c, medication reductions

o Harms: Any (including hypoglycemia)

• Timing: Last 5 years (2015-2020)

• Setting: Any

• Study design: Any
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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METHODS

SEARCHES AND STUDY SELECTION

To identify articles relevant to the key questions, our research librarian searched Ovid 

MEDLINE, CINAHL, and Ovid CENTRAL databases as well as AHRQ, Cochrane, HSR&D, 

and Clinicaltrials.gov websites using terms for type 2 diabetes, self-management, virtual 

programs, and diet from January 2015 to April 2020 (see Supplemental Materials for complete 

search strategies). To accommodate our rapid timeline, we only searched for the most recent 

literature (ie, published in the past 5 years). Our rationale is that the technology supporting 

apps/online programs is rapidly changing, and an app/online program greater than 5 years old is 

unlikely to currently be available to patients. We limited the search to published and indexed 

articles involving human subjects available in the English language. 

Additional citations were identified from hand-searching reference lists and consultation with 

content experts. We also developed a list of companies who are currently marketing virtual 

diabetes diet programs to people with type 2 diabetes (Better Therapeutics, CappaHealth [My 

Dietitian], Diabetes.co.uk [Low Carb Program], Diab Memory, Noom [Noom Coach], Second 

Nature [Our Path], and Virta Health) from our list of included studies. We contacted these 

companies to request unpublished data. 

Study selection was based on the eligibility criteria described above. Titles, abstracts, and fulltext articles were reviewed by 1 investigator and checked by another. All disagreements were 

resolved by consensus.

QUALITY ASSESSMENT & DATA EXTRACTION

We used Cochrane’s Risk of Bias 2 Tool to rate the internal validity of controlled trials.24 We 

rated the internal validity of cohort studies, longitudinal single-armed studies, and pre-post 

studies based on the Cochrane ROBINS-I.25 We abstracted data from all studies and results for 

each included outcome. All data abstraction and internal validity ratings were first completed by 

one reviewer and then checked by another. All disagreements were resolved by consensus.

STRENGTH OF EVIDENCE ASSESSMENT

We informally graded the strength of the evidence based on the AHRQ Methods Guide for 

Comparative Effectiveness Reviews.26 This approach incorporates 4 key domains: risk of bias 

(includes study design and aggregate quality), consistency, directness, and precision of the 

evidence. Strength of evidence is graded for each key outcome measure and ratings range from 

high to insufficient, reflecting our confidence that the evidence reflects the true effect.

SYNTHESIS OF DATA 

Due to heterogeneity in participant characteristics, intervention components and length of 

follow-up, we synthesized results narratively. In our synthesis, we highlighted which programs 

demonstrated a clinically meaningful change on weight loss, HbA1c, or medication reduction, 

without harms. Table 2 outlines what we considered to be a clinically meaningful change for 

each outcome. Although HbA1c reduction ≥ .5% is not a clinically meaningful outcome in and 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

11

of itself, we have included it here as HbA1c level has been shown to be directly related to 

diabetes-related complications.27 

Table 2. Definitions of Clinically Meaningful Change by Outcome

Outcome Clinically meaningful change

Weight loss Weight loss ≥ 5% from baseline28

Reversal of diabetes Lowering HbA1c to level < 6.5% (diagnostic threshold for type 2 

diabetes) without medications

HbA1c Lowering of HbA1c level ≥ .5% from baseline27

Medication reduction Discontinuation of ANY diabetes-related medication

Discontinuation of ALL diabetes-related medication 

Harms Serious or severe treatment-related adverse events

In our synthesis, we also comment on whether participants were in the normal weight range 

(BMI 18.5 to < 25 kg/m2), overweight (BMI 25 to < 30), obese (BMI 30 to < 40), or severely 

obese (BMI 40 or higher) at baseline according to CDC guidelines.29 We discuss results from 

intent-to-treat analyses unless otherwise described. The complete description of our full methods 

can be found on the PROSPERO international prospective register of systematic reviews

(http://www.crd.york.ac.uk/PROSPERO/; registration number CRD 42020180278).
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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RESULTS

The literature flow diagram (Figure 1) summarizes the results of the search and study selection 

processes. Among 622 potentially relevant citations, we included 18 articles of 15 studies (9

RCTs,30-38 1 non-randomized trial,

11,39-41 3 single-arm longitudinal studies,42-44 and 2 pre-post 

studies45,46) of 14 virtual diabetes diet programs (TeLiPro,30 Virta Health,11,39-41 Low Carb 

Program,42 Better Therapeutics,45 u-Healthcare,32,33 ANODE,31,43 Our Path (Second Nature),46

GlycoLeap,46 My Dietitian,34 Noom Coach,35 DiabMemory + Nutrinaut,44 and 3 unnamed 

programs).

36-38 Studies varied considerably in terms of the diet program provided; as a result, we 

organized our results into 3 parts: part 1– programs promoting a named diet; part 2– programs 

that promote healthy eating based on a diabetes or dietary guideline; and part 3– programs that 

promote healthy eating not based on a named diet or guideline.

Across studies, participant characteristics were heterogenous: mean baseline BMI ranged from 

27 to 40 kg/m2, HbA1c from 5.9% to 9.1%, and length of time diagnosed with diabetes from 3 to 

17 years. Study size ranged from 24 to 1,000 participants. Outcomes were measured between 10 

weeks and 2 years after program initiation, although most studies measured outcomes at either 3 

months, 6 months, or 1 year. Detailed study-level data abstraction and quality assessment appear 

in the Supplementary Materials. Table 3 provides a high-level overview of each programincluding program features; whether the program was associated with clinically meaningful 

improvements in weight, HbA1c, and medication use without severe or serious harms; and the 

number and types of studies evaluating each program. 

From our outreach to companies marketing virtual diabetes programs to patients, we only 

received a response from Virta Health. We have incorporated a summary of findings from 

relevant conference abstracts provided by Virta in the “Virta Health” section, but did not 

formally include these articles in our report. 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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LITERATURE FLOW

Figure 1: Literature Flowchart

Records identified through database searching 

(n=1,092) 

Medline=558

CDSR=73

CCRCT=223 

CINAHL=238 

Records identified through 

reference lists and grey 

literature searching 

(n=9)

Records remaining after 

removal of duplicates

(n=622)

Records remaining after title 

and abstract review

(n=45)

Records remaining after fulltext review and included in 

synthesis

(n=18)

Excluded (n=577)

Excluded (n=27)

-Ineligible population (n=2) 

-Ineligible intervention (n=8) 

-Ineligible outcome (n=3) 

-Ineligible publication type (n=13) 

-Unable to locate full-text (n=1) 

Identification Screening / Eligibility Included 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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Table 3. Overview of Studies on Virtual Diabetes Diet Programs

Program Diet Coaching Additional features of program Outcomes Number and type of 

studies

Health coach by personHealth coach by algorithmEducational classes/ Health data trackingMedication managementPeer supportPhysical activity↓ Weight >5%↓ HbA1c >.5%Stopped medicationsNo harms foundMaintained 1+ yearsRCTNonrandomized controlledSingle-arm longitudinalPre-post 

Programs promoting a named diet

TeLiPro30 Meal 

replacement ● ● √ √ √ 1 

Virta 

Health11,39-41 Ketogenic ● ● ● ● ● √ √ √ √ √ 1 

Low Carb 

Program47

Low 

carbohydrate ● ● ● ● - √ √ √ 1

Better 

Therapeutics

45

Plant-based ● ● ● ● ● √ √ √ 1 

Programs promoting healthy eating based on guidelines

uHealthcare32,3

3

US and 

South Korea 

guidelines

● ● ● - √ 2 

ANODE31,43 France 

guidelines ● ● ● - - 1 

Our Path 

(Second 

Nature)46

UK

guidelines ● ● ● ● ● √ √

1

GlycoLeap46

US and 

Singapore 

guidelines

● ● ● ● - √ 1 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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● denotes this feature was present. Outcomes √= target achieved; - = target not achieved; blank= not measured. 

For HbA1c, target was achieved if mean HbA1c ↓ .5% at follow-up in the intervention group. For weight, target was achieved if mean weight ↓ 5% at follow-up in 

intervention group. For medications, target was achieved if any intervention participants stopped taking medications. For harms, target was achieved if no serious or 

severe diabetes-related harms were reported by intervention participants. For maintenance, target was achieved if any benefits in weight, HbA1c, or weight were 

maintained for 1+ years. 

Program Diet Coaching Additional features of program Outcomes Number and type of 

studies

Health coach 

by person

Health coach 

by algorithm

Educational 

classes/ 

Health data 

tracking

Medication 

managementPeer support

Physical 

activity

↓ Weight >5%

↓ HbA1c >.5%

Stopped 

medications

No harms 

found 

Maintained 1+ 

years

RCT

Nonrandomized 

controlled

Single-arm 

longitudinal

Pre-post 

Programs promoting healthy eating not based named diet or guidelines 

My Dietitian34 Meal tracking ● ● ● ● - - 1 

Noom 

Coach35

Diet 

education & 

tracking

● ● ● ● √ √ 1 

Unnamed 

program 

(Wayne 

2015)38

Diet 

counseling &

tracking 

● ● ● ● - √ 1 

Unnamed 

program (Sun 

2019)36

Diet 

counseling & 

tracking

● ● ● √ 1 

Unnamed 

program (Von 

Storch 

2019)37

Diet 

counseling & 

tracking 

● ● ● - 1 

DiabMemory 

+ Nutrinaut44

Diet 

counseling & 

tracking

● ● ● - 1 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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PART I: PROGRAMS PROMOTING A NAMED DIET

Overview

Four studies (1 RCT,30 1 non-randomized trial,11,39-41 1 single-armed longitudinal study,42 and 1 

pre-post study45) examined virtual diet programs promoting named diets where certain categories 

of food or macronutrients were limited. Named diets included a meal replacement diet,30 a 

ketogenic diet,11,39-41 a low carb diet,42 and a plant-based diet45 (Table 4). Overall, virtual

programs based on named diets were associated with weight loss (3-12%), HbA1c reductions 

(.8-1.4%), and reductions in medication use (9-40% of those taking diabetes medications at 

baseline stopped taking them) with no treatment-related harms. By comparison, those receiving 

usual care did not experience improvements in any of these measures. In 1 study, improvements 

in the intervention group were maintained for 1 year even after the intervention ended at 12 

weeks; in a second study, improvements were maintained for 1 year when participants continued 

to receive the intervention; and in a third study, improvements were maintained for 2 years when 

participants continued to receive the intervention. Overall, we have low confidence in these 

findings as each program was only evaluated in a single study, only 2 studies had separate 

control groups, and in 1 controlled study those in the intervention group were considerably 

different (ie, higher BMI, lower rates of insulin use) than those in the control group at baseline, 

among other important limitations. 

Table 4. Detailed Findings from Studies of Named Diet Programs 

Study Characteristics Weight Loss HbA1c Reduction Medication use Serious or 

severe harms

TeLiPro30

12-week meal replacement 

program (I) vs routine care (C)

RCT (N = 202)

• 12 wks: ↓6% (I) 

vs no change (C)

• 6 mo & 1 yr: 

weight loss 

maintained

• 12 wks: ↓1.1% (I) 

vs no change (C)

• 6 mo & 1 yr: 

HbA1c reductions 

maintained

NR NR

Virta Health11,39-41

2-year continuous care 

intervention based on 

ketogenic diet (I) vs usual care 

(C)

Non-randomized trial (N =349) 

• 10-11 wks: ↓7% 

(I)

• 1 yr: ↓12% (I) vs 

no change (C)

• 2 yrs: ↓10% (I) vs 

no change C)

• 10-11 wks: ↓1% (I)

• 1 yr: ↓1.4% (I) vs 

no change (C) 

• 2 yrs: ↓1% (I) vs no 

change (C)

• 10-11 wks: 9% 

stopped taking 

medication (I)

• 1 yr: ↓27% taking 

metformin (I) vs 

no change (C)

• 2 yrs: ↓13% 

taking insulin (I) 

vs no change (C)

•10-11 wks:

No 

hypoglycemia 

(I)

•1 yr: No 

metabolic 

acidosis (I & 

C) 

Low Carb Program42

1-year low carbohydrate diet

program 

Single-arm longitudinal study

(N = 1,000)

1 yr: ↓3.3% 1 yr: ↓.8% 1 yr: 40% stopped 

taking hypoglycemia 

medication 

NR

Better Therapeutics45

12-week plant-based diet 

program

NR 3.5 mo: ↓.8% 3.5 mo: 17% 

decreased dosage 

or stopped taking 1 

or more diabetic 

medications.

3.5 mo: no 

treatmentrelated 

adverse 

events.
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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Study Characteristics Weight Loss HbA1c Reduction Medication use Serious or 

severe harms

Pre-post study (N =118)

↓=decrease; ↑=increase; I= intervention; C=Control; NR=Not reported; Italics= Meets criteria for a minimum 

clinically important difference

TeLiPro (Meal Replacement Diet)

Study Design

A RCT30 (N = 202) conducted in Germany evaluated the effect of the TeLiPro intervention, a 12-

week, virtual, meal-replacement diet intervention. Participants were recruited from attending 

physicians or newspaper articles. In this intervention, participants consumed a meal-replacement 

product (dissolvable in water) for 3 meals/day, gradually decreasing the proportion of meals that 

came from meal replacements over a 12-week period. Coaching consisted of a weekly call from 

a diabetes coach (20 min duration). Participants also received devices to help them self-monitor 

glucose levels, weight, and physical activity, and measurements were automatically transferred 

to a personalized online portal. The control group received routine care every 3 months from a 

physician. At baseline, participants weighed on average between 35.3 kg/m2

 (intervention) and 

37 kg/m2 (control), had an average HbA1c level between 8.2% (control) and 8.4% (intervention), 

had been diagnosed with diabetes for 11 years, and were taking at least 2 diabetes medications.

Outcomes were measured at 12 weeks, 6 months, and 1 year. 

Results

Intervention group participants lost on average of 6% of their body weight at 12 weeks and 

maintained these reductions at 6 months and 1 year, while the control group did not lose weight 

at any time point. The intervention group also reduced their HbA1c level by 1.1% (8.4% to 

7.3%) at 12 weeks, while the control group experienced no change. HbA1c reductions were 

generally maintained, although both intervention and control groups had an increase of 0.1-0.2% 

HbA1c at 6 months and 12 months. The study did not report medication use or harms. 

Limitations

High rates of attrition (44% of control participants and 25% of intervention group participants 

did not complete data assessments at 1 year) were a major limitation of this study, although 

intent-to-treat analyses were used to account for missing data.

Virta Health (Ketogenic Diet) 

Study Design

A non-randomized clinical trial11,39-41 (N = 349) conducted in the US comparing Virta Health (a

virtual intervention based on the ketogenic diet) to usual care. One of these articles describe prepost differences in the intervention arm at 10-11 weeks,39 while the others describe betweengroup differences at 1 year11,40 and 2 years.

41 In the study, eligible participants chose to enroll in 

the Virta Health program (a “continuous care intervention” that provided support from a personal 

health coach as well as physician-directed medication management, diabetes education, data 

tracking, and peer support) or to receive usual care (care from a PCP or endocrinologist with 

counseling from an RD according to ADA recommendations). Goals of the ketogenic diet were

to consume < 30 g carb, 1.5 g/kg protein, dietary fats to satiety, 3-5 servings non-starchy 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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vegetables, and to intake adequate mineral and fluids each day. Personal health coaching was 

available through 1-on-1 texting. At baseline, participants in the intervention group (N = 262)

had an average BMI of 40.4 kg/m2 (severely obese) and 30% were taking insulin, while those in 

the control group (N = 87) had an average BMI of 36.7 kg/m2 (obese) and 46% were taking 

insulin. Length of time diagnosed with diabetes (8 years) and HbA1c (7.6%) were similar 

between groups. Participants received the intervention for 2 years, although the frequency of 

classes (delivered either in person or virtually) decreased over time. Data was collected at 10-11 

weeks, 1 year, and 2 years. 

Results

Those in the intervention group lost 7% of their body weight at 10-11 weeks,39 12% at 1 year,11

and generally maintained the weight loss at 2 years,41 while those in the usual care group did not 

lose weight at 1 or 2 years. Intervention group participants also lowered their HbA1c levels by

1% (7.6% to 6.6%)39 at 10-11 weeks, by 1.4% at 1 year,11 and maintained reductions at 2 years, 

while those in the usual care group did not experience any reductions in HbA1c. Additionally, 

there was an increase in the percentage of people in the intervention group who successfully 

reversed their diabetes (defined as HbA1c <6.5% without medications or with just metformin) at 

2 years (12% to 54%), while there was a decrease in the control arm (16% to 9%).41 The 

percentage of participants in the intervention group taking any diabetes medication (except 

metformin) decreased from 57% to 30% at 1 year and the percentage taking insulin decreased 

from 30% to 17% at 1 year, compared to no change in the control group.11 Authors reported no 

participants in the intervention group experienced hypoglycemia during the first 10-11 weeks, 

and no participants experienced metabolic acidosis in either group in the first year. Attrition was 

26% in the intervention group and 22% in the control group at 2 years. 

Additional data are available on participants in Virta Health’s non-randomized controlled trial 

via conference abstracts, but these data have not been peer-reviewed.48-50 We briefly discuss 

these findings here, but do not formally include the abstracts or evaluate study quality given the 

more limited information available in abstracts. Readers should interpret these results with 

caution. In one abstract,

48 Virta Health program participants who completed outcome 

assessments at 3.5 years lowered their HbA1c by 0.6% (7.4% to 6.8%) and lost 9% of body 

weight (117 to 106.5 kg) from baseline. In addition, the percentage of participants that were not 

taking diabetes medication increased from 15% to 33%, and 45% of participants had lowered 

HbA1c < 6.5% with the use of metformin or no medication. Overall, these results indicate the 

benefits of the program are maintained long-term in this selected population, although there is 

some rebound effect as both HbA1c and weight were higher at 3.5 years than at 1 or 2 years. A 

second abstract49 examined predictors of HbA1c reduction and weight loss, and found that early 

nutritional ketosis (measured as percentage of blood beta-hydroxybutyrate (BHB) readings ≥ 0.5 

mm) was a predictor of weight loss and HbA1c reduction, but engagement in the app (measured 

as percentage of days participants messaged their coach and logged ≥ 1 biomarker or symptom)

was not. A third abstract50 found that shorter diabetes duration and lower HbA1c at baseline were 

associated with success lowering of HbA1c < 6.5% with either metformin or no medication. 

Limitations

This study had several major limitations. The first was the use of non-randomized methods to 

assign participants into groups, resulting in measurable and potentially unmeasurable differences

which make it difficult to establish causality between the intervention and outcomes. The control 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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group was designed to be a “reference for typical disease treatment and progression over 1 year 

within the same geographical, health care, and laboratory locations” as the intervention group.11

The control group had a “separate information session and informed consent” process, although 

they were notified that the trial had an intervention arm and could participate in that arm if they

liked.11 The result of having a non-randomized process for assigning patients to groups is that the 

groups were different at baseline in several measurable ways. Those in the intervention group 

had a higher average BMI and a lower proportion who used insulin (although authors controlled 

for BMI and insulin use, among other baseline participant characteristics, in between-group 

analyses). An additional concern with non-randomly assigning people to groups is that the 

groups could be different in non-measurable ways – such as the intervention group being more 

motivated to lose weight and therefore choosing to be in a more intensive intervention. 

The second major limitation is that researchers revised the study’s Clinicaltrials.gov protocol22

over time without providing a justification for why changes were made, which could have 

contributed to reporting bias. A comparison of the originally submitted Clinicaltrials.gov 

protocol from August 2015 versus a revised version from January 2018 indicates that researchers 

lengthened the study follow-up period (from 2 years to 5 years), added 3 secondary purposes (to 

compare in-person versus web-based delivery of education content, to explore relationships in 

LDL cholesterol and carotid intima media thickness, and to evaluate whether health outcomes 

are maintained and what the economic effects are over 5 years), and specified that at the 3-month 

time point, outcomes would only be collected in the intervention arm. Making unjustified 

changes to a protocol can lead to reporting bias, as it can make it appear that researchers intended 

to measure a certain outcome or to evaluate a certain question, when in reality, it was the result 

of an interim analysis or other factors. The August 2018 revision that clarified that 3-month 

outcomes would only be measured in the intervention group is especially problematic as it 

occurred after the first article39 on this study was published in August 2017 examining 10-11 

week outcomes in the intervention group only.

The third major limitation of this study is that results are spread out over 6 published articles (4

that were included and 251,52 that were not), which could have contributed to publication bias. 

While unique outcome data are presented in each article, some outcomes are reported in multiple 

studies (such as 1-year outcomes, which were the focus of the Hallberg 2018 article39 but were 

also reported in the Athinarayanan 2019 article41 which examined whether outcomes were 

maintained at 2 years). Publishing multiple articles on a single study, sometimes referred to as 

data fragmentation or “salami-slicing,” can lead to publication bias and has been discussed

frequently in editorials as a common but problematic practice.

53,54 In terms of this study, 

splitting outcomes across 6 articles is an issue because 1) it makes it appear to a casual reader 

that there are more data supporting the intervention than there truly are and 2) it makes it 

difficult to see the “big picture” of how the intervention impacted the researcher’s primary

outcomes of interest.

Low Carb Program (Low Carbohydrate Diet)

Study Design

A single-arm, longitudinal study42 (N = 1,000) conducted in the UK evaluated the effects of the 

online Low Carb Program, a low carbohydrate intervention that also included automated 

feedback and tracking of health data. Patients were recruited from convenience samples 

following the 2015 online launch of the Low Carb Program. Goals of the low carbohydrate diet 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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were to restrict carbohydrates based on visual plate method and increase intake of green 

vegetables as well as low-glycemic index fruits and fats. Coaching consisted of weekly 

automated emails based on program use. Participants were encouraged to have regular contact 

with their health care providers to adjust medications in weeks 1, 2, and 10, although these 

providers were not part of the Low Carb program. Participants received 10 weeks of educational 

coursework, but could continue to access the coursework, track data, and access a discussion 

board for up to a year. At baseline, participants weighed an average of 89.6 kg, had a HbA1c of 

7.8% and many had comorbidities including hypertension (40%) and high cholesterol (35%). 

Outcomes were measured at 1 year. 

Results

Participants lost on average of 3.3% of their body weight at 1 year, which was not a clinically 

meaningful change. However, those who completed the program (ie, finished all 10 educational 

modules) did have a clinically meaningful reduction in weight (8%) while those who partially

completed or did not complete the program had no change in weight. At 1 year, participants 

lowered their HbA1c on average by 0.8% (7.8% to 7%), with a dose-response relationship 

between completion of the program and outcomes (completers lowered HbA1c by 1.2%, partial 

completers by 0.6%, and non-completers had no change). At 1 year, 40% of those who were 

prescribed hypoglycemia medications at baseline stopped taking 1 or more medications. 

Limitations

The major limitation of this study was the lack of control group, making it impossible to 

determine if the intervention caused outcomes, or other potential confounders or co-occurring 

interventions. Additional methodological limitations include poor adherence to the intervention 

(only 52% of participants completed all 10 educational modules) and high attrition (30% of 

participants did not report outcomes at 1 year), although authors used intent-to-treat analyses to 

account for missing data and explored differences for completers, partial completers, and noncompleters. 

Better Therapeutics (Plant-based Diet)

Study Design

A pre-post study45 (n=118) conducted in the US examined the effect of a 12-week app-based 

intervention (Better Therapeutics) that promoted a plant-based diet. Participants were recruited 

through advertisements on Facebook and Craigslist. Once enrolled, participants were encouraged 

to use the meal planning feature of the app (5 min/week), review educational materials on 

culinary or health topics (15-20 mins/week) and report meals (1-2 min/day). Health coaching 

was provided for 30 minutes every 2 weeks by phone, and a clinical team was available for 

additional support when needed. Additional features of the intervention included access to 

support groups and encouraging participants to monitor weight and engage in physical activity. 

At baseline, participants had an average BMI of 38.1 kg/m2 (obese), HbA1c of 8.1%, and had 

been diagnosed with diabetes for 2.6 years. Outcomes were measured at 3.5 months. 

Results

Weight loss was not reported in this study. However, at 3.5 months, participants lowered their 

HbA1c by an average of 0.8% (8.1% to 7.3%) and 17% reported either reduced dosage or 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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stopped taking their diabetic medications altogether. Authors reported no treatment-related 

adverse events occurred. 

Limitations 

The major limitation of this study was the lack of a control group that could rule out the 

possibility that effects were due to confounding or co-interventions. A minor limitation was that 

HbA1c was self-reported (rather than measured via a glucometer that automatically transferred 

readings to the study team) increasing the potential risk for measurement error or bias. 

PART 2: PROGRAMS THAT PROMOTE HEALTHY EATING BASED ON 

GUIDELINES

Overview

Five studies (3 RCTs,31-33 1 single-arm longitudinal study,43 and 1 pre-post study46) evaluated 4 

virtual diabetes diet programs (u-Healthcare,32,33 ANODE,31 Our Path,43 and GlycoLeap46) that 

promoted healthy eating based on national dietary or diabetes guidelines (Table 5). Overall, 

virtual healthy-eating programs based on guidelines had mixed effects on weight, with only 

OurPath demonstrating a clinically significant effect (7% reduction at 1 year). The u-Healthcare 

and GlycoLeap programs were both associated with > 0.5% decreases in HbA1c between 3-9 

months, although clinically significant improvements were also seen in the u-Healthcare study’s 

control group at 3-6 months. No studies evaluated the percentage of participants who stopped 

using diabetes medications- although the u-Healthcare study noted that 12% reduced their 

medication dosage. None of these studies reported on harms, so it is unclear if there are any 

potential downsides to these virtual programs. Overall, we have low confidence in these findings 

as each program was only evaluated in 1 study (with the exception of u-Healthcare which was 

evaluated in 2), only 3 studies had separate control groups, and 2 of the 3 controlled studies had

either high attrition (> 20%) or differential attrition between groups. 

Table 5. Detailed Findings From Studies of Programs That Promote Healthy Eating Based 

on Guidelines

Study Characteristics Weight Loss HbA1c Reduction Medication use Serious or 

severe harms

u-Healthcare32,33

6-month therapeutic lifestyle 

intervention w/ counseling (I) 

vs counseling alone (C)

2 RCTs (N=70 & N=100)

• 3 mo: NR

• 6 mo: ↓2% (I) vs 

0% (C)

• 3 mo: ↓.8% (I) vs 

↓ .8% (C)

• 6 mo: ↓.7%-1.1% 

(I) vs .2-.5% (C)

6 mo: 12% of ppts 

reduced dosage of 

oral antidiabetic drugs 

or insulin (I) vs no 

change (C)

NR

ANODE31

16-week nutritional support & 

education intervention (I) 

based on guidelines vs usual 

care (C)

RCT (N= 102)

16 wks: ↓2.5% (I) 

vs no change (C)

16 wks: ↓.4% (I) vs 

↑.2% (C)

NR NR
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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Study Characteristics Weight Loss HbA1c Reduction Medication use Serious or 

severe harms

Our Path (now Second 

Nature)43

3-month behavior coach 

program

Single-arm, longitudinal study 

(N=896)

• 6 mo: ↓8%

• 12 mo: ↓7%

NR NR NR

GlycoLeap46

6-month meal tracking 

intervention based on US & 

Singapore’s guidelines

Pre-post study (N=100)

9+ mo: ↓2.5% 9+ mo: ↓1% NR NR

↓=decrease; ↑=increase; I= intervention; C=Control; NR=Not reported; Italics= Meets criteria for a minimum 

clinically important difference

u-Healthcare (US & South Korea Guidelines)

Study Design 

Two RCTs (N = 7033 and N = 10032) conducted in South Korea evaluated the u-Healthcare 

program, a therapeutic lifestyle program focused on diabetes management, compared to usual 

care. One RCT33 (ie, Kim 2015) evaluated a version of u-Healthcare that had a voice inception 

software similar to speech-to-text where participants could verbally report their blood glucose to 

a device and it would record it, while the other RCT32 (ie, Lim 2016) did not include this 

software. Participants were recruited from an outpatient clinic of a university hospital. In both 

RCTs, intervention and control groups received the same diet and exercise counseling 

intervention prior to randomization. This counseling was characterized as meeting standards set 

by the American Diabetes Association and the Korean Diabetes Association in both studies, and 

Lim 2016 described the counseling as involving an individual assessment of dietary habits, 

nutritional education from a dietitian, recommendations to monitor blood glucose at least 8 times 

a week, and check-ins at 3 and 6 months. In both studies, the intervention group had access to the 

u-Healthcare system that helped them to track their blood glucose, submit it to a study database, 

and receive feedback from an algorithm, as well as track physical activity. Control group 

participants monitored blood glucose and physical activity without access to this system. 

At baseline, participants had an average BMI ranging from 25.1 kg/m2

 to 25.9 kg/m2

(overweight), HbA1c from 7.9% to 8.7%, and had been diagnosed with diabetes for 14.4 to 16.6 

years (all participants were 60+ years old, per study eligibility criteria) depending on the study 

and group. Many participants also had comorbidities (46-51% hypertension; 66%-71% 

dyslipidemia, 14-26% CVD; retinopathy 14%; and neuropathy 10-18%) depending on the study 

and group. Outcomes were measured at 3 and 6 months. 

Results

All findings in this section are from pre-protocol analyses. In Kim 2015,33 intervention group 

participants lost 2% of their body weight while control group participants did not lose any weight 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

23

at 6 months- neither represented a clinically significant change. Lim 201632 did not measure 

weight loss, although intervention participants lowered their BMI (26.3 to 25.7 kg/m2

) at 6 

months. This change as not seen for the control group (26.8 to 26.5 kg/m2). 

In both studies, intervention participants experienced reductions in HbA1c at follow-up; 

however, results in control groups were mixed. In Kim 2015,33 both groups experienced 

clinically meaningful reductions in HbA1c, although the intervention group had greater 

reductions at 6 months (-1.1% [8.6% to 7.5%] in intervention vs - 0.5% [8.7% to 8.2%] in 

control). In Lim 2016,32 HbA1c was lowered by 0.7% at 3 months in the intervention group 

which was maintained at 6 months (8% to 7.3%)- a clinically meaningful change. In the control 

group, HbA1c was lowered at 3 months (number not reported) but rebounded at 6 months to a 

value that was not clinically different from baseline (8.1% to 7.9%). 

Lim 201632 reported that 12% of intervention group participants reduced their dosage of oral 

antidiabetic drugs or insulin compared to no change in the control group. Harms were not 

reported in either study.

Limitations

This study had minor limitations, primarily from reporting per-protocol results instead of intentto-treat results. In Kim 2015,33 only 3% of participants dropped out, so per-protocol analyses 

likely provide a good estimate of the effect of assignment to intervention. However, for Lim 

201632 between 14-16% of participants dropped out and although authors conducted both perprotocol and intent-to-treat analyses, most of the reported data is from per-protocol analysis. Perprotocol results may be biased as they do not account for people who dropped out of the study. 

ANODE (France Guidelines)

Study Design

An RCT31 (N = 120) conducted in France evaluated ANODE, an online nutritional support tool 

designed to improve diet and physical activity according to France’s National Nutrition and 

Health program guidelines, versus usual care with a GP or specialist. Participants were recruited 

from media advertising or directly referred by their caregivers. Intervention participants 

completed 4 online educational modules on diet and physical activity (1- self-monitoring diet 

and physical activity; 2- nutritional assessment; 3- balanced diet menu generator; and 4- physical 

activity education and prescription). Coaching consisted of participants entering their meal 

information into the support tool and received automated feedback summarizing the amounts of 

macro-nutrients consumed (fat, saturated fat, protein, salt, carbohydrates) as well as advice on 

how to achieve a balanced diet. Human contact was limited to a hotline support in case of 

technical issues. At baseline, participants had a BMI of 33.4 kg/m2 (obese) and HbA1c of 7.2% 

(diabetes duration not reported). Outcomes were measured at 16 weeks. 

Results

Intervention group participants lost on average 2.5% of their body weight at 16 weeks, which 

was not a clinically meaningful change (by contrast, control group participants did not lose 

weight). Those in the intervention group lowered their HbA1c by 0.4% (from 7.2% to 6.8%) 

which was also not a clinically meaningful change (by contrast, those in the control group had an 

average increase of HbA1c of 0.2%). Medication use and harms were not reported. 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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Limitations

This study had minor limitations: participants and coaches were aware of the assigned 

intervention during the trial, and attrition was higher in the intervention versus control group (11 

vs 5 participants) due to lack of interest. 

Our Path (UK. Guidelines)

Study Design 

A single-arm, longitudinal study43 (N = 896) conducted in the UK evaluated the Our Path (now 

known as Second Nature) program, a 3-month, app-based, behavior change program. 

Participants in this study either paid for the app or were referred from their general practitioner 

(GP) for treatment of type 2 diabetes (in which case, the app was free). Participants in this 

intervention reviewed educational articles on nutrition and health topics (10-15 min/article), were 

matched to a 10-person peer support group, had the option to text a health coach (a registered 

dietitian or nutritionist) 1-on-1 through the app, and received a physical activity tracker and a 

scale. Health coach advice was informed by the National Institute of Health and Care (NICE) 

guidelines. The intervention was split into 2 parts: a 12 week “core” phase that was more 

intensive, and a “sustain” phase where participants could no longer text a health coach but could 

access other features of the app. Of the 896 participants who completed data assessments at 6 

and 12 months (an inclusion criterion for the study), 52% had type 2 diabetes and received 

access to the program through their GP. At baseline, participants with type 2 diabetes had an 

average BMI of 33.4 kg/m2 (obese). 

Results

At 6 months, participants with type 2 diabetes lost an average of 8% of their body weight and 

maintained the weight loss at 1 year. HbA1c, medication use, and harms were not reported. 

Authors noted that 56% of participants with type 2 diabetes lost >5% of their body weight at 1 

year, and 25% lost > 10%. 

Limitations

Results from this study (N = 896) represented only those who took part in the program who 

completed 6- and 12-month weight readings, which was about 25% of the total population who 

participated in the Our Path program during the study time period. Therefore, results likely 

reflect people who were more engaged with the program. The lack of control group also makes it 

difficult to determine if it was the intervention or a confounder/cointervention that drove the 

change in outcomes. 

GlycoLeap (US and Singapore Guidelines) 

Study Design 

A pre-post study46 (N = 100) conducted in Singapore evaluated 6 months of access to 

GlycoLeap, an online lifestyle management intervention. Participants were recruited from a 

single community health care facility. Intervention participants tracked meals and interacted with 

health coaches who provided recommendations, encouragement, and personalized feedback on 

progress. Twenty-four educational lessons on diabetes and self-management were available to 

participants based on the 7 healthy self-care behaviors recommended by American Association 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

25

of Diabetes Educators. After participants entered their meal information online, health coaches 

rated each meal for nutritional content on a 1 to 5 scale based on Singapore’s Health Promotion 

Board’s national dietary guidelines. Additional features of the program included tracking of 

weight, blood glucose, and physical activity. At baseline, participants had an average BMI of 

29.8 kg/m2 (overweight), HbA1c of 8.8%, and had been diagnosed with diabetes for 9.3 years. 

Outcomes were measured after the 6-month intervention, although the actual time point varied

for each individual (eg, weight and HbA1c was measured between 12-38 weeks after 

intervention). 

Results

Intervention participants reduced their HbA1c by 1% (8.8% to 7.8%) which was a clinically 

meaningful change. However, they only lost an average of 2.5% of their body weight (although 

authors note that 17% of participants did lose > 5%). Medication use and harms were not 

reported by the study. 

Limitations

This study had major limitations, most notably a lack of control group that could have ruled out 

the possibility effects were due to confounders or co-interventions. In addition, the large period 

in which outcomes were measured (12-38 weeks after intervention) makes it difficult to interpret 

the meaning of the data reported. 

PART 3: PROGRAMS THAT PROMOTE HEALTHY EATING NOT 

BASED ON NAMED DIET OR GUIDELINE

Overview 

Six studies (5 RCTs34-38 and 1 pre-post study)44 evaluated 6 virtual diabetes diet programs (My 

Dietitian,34 Noom Coach,35 Diab Memory + Nutrinaut,44 and 3 programs36-38 that were unnamed) 

that promoted healthy eating but were not based on a named diet or guideline (Table 6). Overall, 

2 RCTs34,38 evaluated the impact of 2 programs (My Dietitian and an unnamed program by 

Wayne 2015) on weight, neither of which showed a clinically significant reduction at any time 

point. Four RCTs35-38 evaluated the impact of 4 programs (Noom Coach as well as unnamed 

program by Wayne 2015, Sun 2019, and Van Storch 2019) on HbA1c: 3 RCTs showed both 

intervention and control groups had reductions > 0.5% in HbA1c while the other RCT did not 

show improvements in either group. Medication use was not reported in any of these studies, and 

only 1 RCT (of the Noom Coach program) indicated the intervention was not associated with 

harms. Overall, we have low confidence in these studies’ findings as each program was only 

evaluated in 1 study, studies were small, and several studies had high rates of attrition. 

Table 6. Detailed Findings From Studies of Programs That Promote Healthy Eating not 

Based on Diabetes or Dietary Guidelines 

Study Characteristics Weight Loss HbA1c Reduction Medication

use

Serious or severe 

harms

My Dietitian34

1-year online weight-loss 

intervention (I) vs usual care (C)

• 3 mo: ↓2% (I) vs 

2% (C)

• 1 yr: ↓4% (I) vs 

2% (C)

NR NR NR
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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Study Characteristics Weight Loss HbA1c Reduction Medication

use

Serious or severe 

harms

1 RCT (N=61)

Noom Coach35

12-week app-based diabetes 

management intervention with 

training from nurse (I) vs training 

from nurse alone (C)

1 RCT (N= 40)

NR 3 mo: ↓1.9% (I) 

vs 1% (C) 

15% (I) and 

20% (C) 

reduced their 

dosage of oral 

antidiabetic 

agents or 

insulin

No severe 

hypoglycemia or 

hospitalization. 

Unnamed program (Wayne 2015)38

6-month self-management 

intervention with vs without mobile 

phone support

RCT (N=131)

6 mo: ↓1% (I) vs 

no change (C)

6 mo: ↓.7% (I) vs 

↓1% (C)

NR NR

Unnamed program (Sun 2019)36

6-month app-based diet tracking + 

counseling intervention vs same 

intervention without use of app or 

continuous feedback 

RCT (N=91)

NR • 3 mo: ↓.8% (I) 

vs .7% (C)

• 6 mo: ↓1% (I) 

vs .7% (C)

NR NR

Unnamed program (Von Storch 

2019)37

12-month telemedicine-assisted 

lifestyle management program vs 

usual care

RCT (N=115)

NR 3 mo:

↓.4% (I) vs no 

change (C)

NR NR

Diab Memory + Nutrinaut44

3-month app-based diet tracking + 

counseling intervention 

Pre-post study (N=24)

NR 3 mo: no change NR NR

↓=decrease; ↑=increase; I= intervention; C=Control; NR=Not reported; Italics= Meets criteria for a minimum 

clinically important difference

My Dietitian

Study Design 

One RCT34 (N = 61) conducted in the UK evaluated My Dietitian, a 1-year, online weight-loss 

program, compared to usual care. Participants were recruited from general practices within 2 

counties. Intervention participants entered in the type, amount, and timing of food consumed 

online, which was converted into a pie chart showing a breakdown of calories consumed by food 

type. Coaching took the form of diet consolations (weekly for first 3 months then monthly for 9 

months) and exercise consultations (same frequency). Participants also could track weight and 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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physical activity and could interact with others in the program through forums, diaries, and chat 

rooms. Control group participants received usual care from a GP. At baseline, participants had a 

median BMI between 33.3-34.4 kg/m2 (obese). All participants were men. Outcomes were 

measured at 12 weeks and 1 year.

Results

At 12 weeks, both intervention and control groups lost 2% of their body weight in per-protocol 

analyses. At 1 year, intervention participants lost 4% of their body weight while the control 

group maintained a 2% weight loss in per-protocol analyses. None of these changes are clinically 

significant. 

Limitations

This study had major limitations, most notably low rates of adherence (fewer than 50% of 

participants adhered to the intervention) and high rates of attrition (39% of intervention and 57% 

of control group dropped out). Researchers also did not conduct intent-to-treat analysis, which 

could have helped to account for dropouts. 

Noom Coach

Study Design 

One RCT35 (N = 40) conducted in South Korea evaluated Noom Coach, a 12-week, smartphonebased, diabetes management intervention. Participants were recruited from a single university 

hospital. Both intervention and control group participants received education from a trained 

nurse at baseline and were encouraged to exercise, but intervention group participants also 

received access to an app where they could track their data (diet, physical activity, blood 

glucose) and receive feedback text messages from a medical team. At baseline, participants had 

an average BMI between 26.8 kg/m2 and 28.9 kg/m2 (overweight), had been diagnosed with 

diabetes for an average of 4-6.6 years, and had an average HbA1c between 8.8% and 9.1%. 

Outcomes were measured at 12 weeks. 

Results

Weight loss was not reported in this study. At 12 weeks, HbA1c levels decreased in both groups 

(-1.9% [from 8.8% to 6.9%] in intervention group vs -1% [from 9.1% to 8.1%] in control group). 

A higher proportion of patients in the intervention group (47%) than in the control group (11%) 

reversed their diabetes (ie, lowered HbA1c < 6.5%). Although the percent of participants who 

stopped taking medication was not reported, 15% of intervention participants and 20% of control 

patients reduced their dosage of oral antidiabetic agents or insulin. Authors reported no serious 

adverse events (such as severe hypoglycemia or hospitalization) occurred. 

Limitations

This was a small study, so the absolute number of participants who experienced improvements 

was low (eg, the 47% of intervention participants who reversed their diabetes represented 8 

people). Other methodological limitations included the fact that participants and outcome 

assessors were aware of which group participants were in, which could have biased results. 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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Unnamed Programs

Study Designs

Three RCTs (N =131,38 N =9136, N =11537) evaluated unnamed programs. One RCT38 (n=131) 

conducted in Canada evaluated a 6-month, mobile phone-based intervention in which both 

intervention and control groups were coached to increase exercise, modify diet to limit 

carbohydrate intake, adhere to medications, and engage with PCPs, but intervention group 

participants had access to an app to help them track health data and either text or schedule phone 

calls with health coaches as needed. A second RCT36 (N =91) conducted in China evaluated a 6-

month, app-based data tracking and counseling intervention compared to usual care. In this 

study, both groups received instructions to monitor health data (physical activity and diet) and 

received dietary and exercise guidance, but only the intervention group could use the app and

receive continuous feedback from coaches and a medical team. A third RCT37 (N =115) 

conducted in Germany evaluated a 12-month telemedicine-assisted lifestyle management 

program compared to usual care. Participants were recruited from outpatient endocrinology 

clinics, primary care clinics, or based on their enrollment in a private insurance company. 

Participants tracked their health data (blood glucose, diet, physical activity) on a tablet and 

discussed progress monthly by phone with a coach who provided support based on stages of 

change theory. Across the 3 studies, average baseline BMI ranged from 23.3 kg/m2 to 37 kg/m2

(overweight-obese), HbA1c from 6.9% to 8.9%, and length of time diagnosed with diabetes from 

7-12 years. In 1 RCT,37 94% of participants had >2 chronic diseases, in another36 all participants 

were >65 years old, and in a third38 participants were recruited from a low-SES community. 

Results

In the first RCT,38 both intervention and control group participants lowered HbA1c > 0.5% (-

0.7%, from 8.7% to 8% in intervention group; -1%, from 8.9% to 7.9% in control group) at 6 

months. In this study, intervention group participants lost 1% of body weight at 6 months – not a 

clinically significant change – while control group participants had no change, in per-protocol 

analyses. In the second RCT,36 both intervention and control participants lowered HbA1c > 0.5% 

at 3 months and maintained changes at 6 months (-0.8%, from 7.8% to 7% in intervention group; 

-0.7% from 7.9% to 7.2% in control group). In this study, weight was not measured, but neither 

group lowered their BMI at 3 or 6 months. In the third RCT,37 intervention participants lowered 

HbA1c by 0.4% (7% to 6.6%) – not a clinically meaningful change – while control group 

participants remained at baseline levels of HbA1c (6.9%) at 3 months, in per-protocol analyses. 

BMI was unchanged in both groups. Medication use and diabetes-related harms were not 

reported by any of these studies, although one RCT38 noted that there were no adverse events 

related to exercise. 

Limitations

Attrition was either high (>26%) or unreported in all 3 studies. Two of the studies36,37 had 

additional methodological issues, including either registering the trial retrospectively36 or not 

registering the trial at all,

37 and there was significantly higher BMI in the intervention than 

control group at baseline in 1 study.37 

DiabMemory + Nutrinaut

Study Design 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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A pre-post study44 (N = 24) conducted in Austria evaluated a 3-month intervention in which

participants used 2 apps (DiabMemory and Nutrinaut) to track health data such as blood glucose, 

weight, and activity (DiabMemory) as well as meals (Nutrinaut). Participants were recruited 

from a disease management program within a national health insurance program. Coaching 

consisted of weekly individual counseling from a dietitian. Although the study describes testing 

the use of these 2 apps in 10 patients with type 2 diabetes, median baseline HbA1c was 5.9% 

(below the diagnostic threshold for diabetes). Baseline BMI was 34.5 kg/m2 (obese). 

Results

Weight was not reported, although authors note that participants lowered BMI by 2.7 kg/m2

. 

There was no effect on HbA1c at 3 months. Medication use and harms were not reported.

Limitations

Given the small sample size (N = 10 people with diabetes) and low levels of HbA1c at baseline, 

this study does not provide much useful information on the effect of these apps for people with 

diabetes. Authors also did not report how they measured outcomes. 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

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SUMMARY AND DISCUSSION

We conducted a rapid evidence review evaluating the last 5 years of research on the 

effectiveness and harms of virtual diet programs that include a coaching component for people 

with diabetes. Although systematic reviews are available on the effectiveness and harms of 

various diets for diabetes15 as well as systematic reviews on virtual programs (including apps, 

websites, and patient portals) for diabetes self-management,19-21 to our knowledge there have 

been no systematic reviews specifically evaluating virtual diet programs. By describing the state 

of the evidence on this topic, this report can help inform the evaluation of the VA and Virta 

Health’s pilot program among Veterans with type 2 diabetes. 

Overall, we identified 1 non-randomized, controlled study on Virta Health and 14 studies of 13 

other virtual diet programs for diabetes. Though the study of Virta Health had important 

limitations, it suggests that for selected patients (ie, those who are severely obese, interested in 

an intensive diabetes management program, and willing to adhere to the ketogenic diet), the 

Virta Health program is associated with improvements in diabetes outcomes such as weight and 

HbA1c. Some patients who participated in Virta Health also stopped taking medications and 

reversed their diabetes (ie, reduce HbA1c <6.5% with no medications or just metformin). 

Improvements were maintained for those who continued to participate in the program at 2 years. 

Three other virtual diet programs for diabetes (TeLiPro, Low Carb Program, and Better 

Therapeutics), all of which delivered a named diet, were associated with a improvements in 2

diabetes outcomes (ie, lowering HbA1c > .5%, weight loss >5%, and/or cessation of any 

medication). Two of these programs (TeLiPro and Low Carb Program) were associated with 

maintenance of improvements for a year or longer. In 1 of these programs (TeLiPro) the 

intervention ended at 12 weeks and in the other (Low Carb Program), participants continued to 

receive the intervention at 1 year. 

Although benefits were more limited, 6 other virtual diet programs (u-Healthcare, Our Path, 

GlycoLeap, Noom Coach, and unnamed programs from Wayne 2015 and Sun 2019) were 

associated with a clinically meaningful improvement in 1 diabetes-related outcome (either 

lowering HbA1c >.5% or weight loss > 5%). In the Noom Coach study, more people reversed 

diabetes (ie, reduced HbA1c <6.5%) in the intervention group than the control group. Perhaps 

not surprisingly, in studies evaluating these 6 programs, participants that were in more active 

control groups (ie, those that received some but not all of the program) were more likely to 

experience improvements in diabetes outcomes than those that were in more passive control 

groups (ie, those who received usual care alone). Results from studies of uHealthcare and Noom 

Coach are especially interesting, as control group participants who received diet counseling from 

a coach experienced clinically meaningful improvements in HbA1c, but intervention group 

participants who received the diet counseling and had access to virtual tools experienced greater

improvements. As a whole, studies in this review illustrate 2 important ideas: 1) most people 

who receive usual care for diabetes do not experience clinically meaningful improvements in 

outcomes such as HbA1c, weight, or medication reductions, and 2) diet counseling from a health 

coach may be associated with clinically meaningful improvements in diabetes-related outcomes,

but the use of technology to facilitate tracking of health data or increase the number of 

touchpoints with a health coach may be associated with additional improvements.
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

31

LIMITATIONS

There were limitations to both our rapid review methods and methodological limitations of the 

included studies. 

Rapid Review Limitations

One limitation of our review was that we only searched for the past 5 years of research on virtual 

diabetes diet programs, and as a result we may have missed older studies. However, we likely 

identified most of the relevant, recent literature on virtual diet programs that are currently 

available to patients. A second limitation is that we had 1 reviewer include studies and abstract

data with second reviewer checking, which could have resulted in missing eligible studies or 

data. However, we made attempts to reduce this risk by establishing explicit inclusion criteria for 

studies and developing and using a piloted data abstraction tool. A third limitation is that we did 

not examine outcomes other than HbA1c, weight loss, medications reductions, and harms. Future 

reviews should examine other patient-important outcomes associated with these programs, such 

as patient satisfaction and quality of life. 

Primary Study Limitations

A major methodological limitation of these studies is that a third (5/15) did not include a separate

control group. As a result, for these studies, it is impossible to rule out the possibility that effects 

were due to either residual confounding or co-interventions that happened at the same time as the 

intervention. Studies also generally relied on volunteers who were interested in an intensive 

diabetes management program and had been screened out through various steps and therefore 

may not be representative of the typical patient with diabetes. 

Of the 10 studies that used control groups, 511,30,31,34,37,39-41 compared an intensive intervention to a 

more passive control group (usual care, typically from a GP or specialist). This is problematic for 

a few reasons. First, from a methodological standpoint, usual care often requires “minimal time 

and effort for the health care provider and/or participant and may be accompanied by low levels 

of interest or belief in its effectiveness”,

55 which can threaten the internal validity of the study. 

As discussed previously, studies in this review indeed found that participants who received usual 

care experienced no improvements in outcomes. This may at least partially be because

participants did not believe usual care would be effective for them. Second, comparing an 

intensive, multi-component intervention to usual care makes it difficult to determine what is 

driving differences in outcomes. For example, in the 2 controlled studies of programs that 

showed a significant improvement in multiple diabetes outcomes compared to usual care

(TeLiPro & Virta Health), we could not determine if it was the diet, the coaching, the tracking of 

health information, or the fact that patients had access to providers on a much more frequent 

basis (in some cases, every day) that caused the outcomes. Only 1 program (Virta Health)

involved practitioners who were able to make adjustments to medications and 1 other (Low Carb 

Program) encouraged participants to regularly contact their providers regarding medication 

adjustments. It is not clear whether this capability is critical, especially if a goal of the coaching 

is to be able to wean some patients off of their diabetes medications. Importantly, we do not 

know to what extent the ketogenic diet was responsible for the improvements that patients 

experienced in the Virta Health study, and whether delivering the same intervention with a 

different diet (such as the Mediterranean diet) would have the same effects.
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

32

Additional limitations seen across studies include high attrition (>20%) or differential attrition 

between intervention and control groups, as well as inconsistent use of and reporting of results 

from intent-to-treat analyses. 

GAPS AND FUTURE RESEARCH

We provide 2 sets of recommendations. The first set of recommendations is for the retrospective 

evaluation of the first group of Veterans enrolled in the pilot project involving Virta. The second 

set of recommendations is for a prospective evaluation of any additional Veterans that may enroll 

in a planned expansion of virtual diet programs being contemplated by the VA. 

Recommendations for the retrospective evaluation of originally enrolled Veterans

Given the effects of Virta Health have only been evaluated in 262 participants that were on 

average severely obese (40.4 kg/m2), it is important to evaluate whether Veterans who may have 

different baseline characteristics and comorbidities can experience similar benefits as those in the 

Virta Health study. We therefore recommend that the pilot project capture as much information 

as is possible on Veteran participants’ baseline characteristics (including BMI, HbA1c, lipid 

levels, diabetes duration, and any comorbidities) as well as outcomes (HbA1c, weight loss, 

medication cessation, and harms) at time points as close as possible to the time points used in the 

Virta Health study (baseline, 3 months, 1 year, 2 years). Given that many Veterans have multiple 

chronic diseases,

56 it is also important to capture whether Veterans participating in Virta Health 

experience any exacerbation of existing conditions or develop any other conditions such as 

coronary artery disease, chronic kidney disease, or diverticulitis. By matching the assessment of

Virta Health among Veterans to the previous assessment of Virta Health in the general 

population, researchers can determine whether the potential impact of the Virta Health program 

appears to be comparable in Veterans and in the general population. This may help in 

understanding how patient characteristics such as baseline BMI and comorbidities affect the 

overall effectiveness of the program. To minimize the potential for attrition bias, outcomes of 

patients who dropped out of the program should be compared to those who stay in the program.

Researchers could consider stratifying by engagement in the program to determine the minimum 

level of engagement needed for a clinically meaningful change in outcomes. Finally, if 

researchers compare those who participated in Virta to those who expressed interest in Virta but 

were not selected for participation, results are likely to be valid for adverse events but not 

necessarily diabetes outcomes. This is because those who are interested in but not selected for 

Virta may have low levels of belief in the effectiveness of usual care, which could theoretically 

affect their diabetes outcomes, but is unlikely to affect the occurrence of adverse events. 

Recommendations for a prospective evaluation of Veterans that may enroll in the 

future

Our primary recommendation for the prospective evaluation of an expanded virtual diet program 

is to use a separate control group that is matched in terms of intensity to the selected program. If 

a program based on a ketogenic diet is chosen by VA, 1 based on an alternate diet (e.g., lowcarb, plant based, Mediterranean or general diabetes guidelines) could be used as a comparator. 

This could help clarify what is driving outcomes and whether any components of the program 

can be modified based on patient preference or need. 
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

33

A recent RCT56 (n=25) evaluated a virtual ketogenic diet program compared to the ADA’s 

"Create Your Plate" diet (neither group received coaching) and found that those in the ketogenic 

group experienced greater improvements in HbA1c, weight loss, and diabetes reversal – although 

the ketogenic group also received additional behavioral help that the control group did not 

receive. Similar to the other studies in this report, this means it is impossible to tell whether it 

was the diet that drove outcome differences, or something else. Therefore, a study that delivers

the same intervention in both groups with the exception of the diet would help to isolate the 

effect of the diet on outcomes. This is a critically important question in VA, as the ketogenic diet 

may be unappealing or contraindicated in some Veterans with type 2 diabetes, and other diets –

such as the Mediterranean diet – have more evidence supporting their long-term cardiovascular 

benefits.57 

In addition to Virta, 3 options of commercially available programs available in English include 

the Low Carb Program (developed in the UK), Better Therapeutics (developed in the US), and 

Our Path (also developed in the UK), all of which showed that participants’ experienced

improvement in either weight or HbA1c. Using a different virtual diabetes diet program as a 

control group would have the added benefit of helping to determine whether different programs 

are acceptable alternatives should a Veteran decline to use a specific diet such as ketogenic diet 

or plant-based diet. A third alternative would be to compare a commercial program to continuous 

care provided by a diabetes educator within the context of an interdisciplinary care team,

58 an 

intervention that is similar in intensity to Virta and other commercial programs but is not 

delivered virtually. The VA’s National Center for Health Promotion and Disease Prevention has 

expanded a program of Telephone Life Coaches who may be able to deliver a comparably 

intensive program.

59

While randomizing patients to either the selected program or a comparator would be the most 

straightforward way to reduce the risk of selection and confounding bias, this might be difficult 

to do outside of a specifically funded research study. It also would not replicate the real-life 

effectiveness of Veterans choosing which diet or program they want to participate in. Therefore, 

one approach researchers could take is to let participants select their preferred program. A 

second approach would be to use an alternative program as a “back-up” in the event participants

could not tolerate the selected diet. This option should only be used if it is not feasible to let 

participants select their preferred program. If participants are not randomized to different groups, 

it would be important to measure, report, and control for baseline factors that can potentially 

confound the results. 

Similar to our recommendations for the retrospective evaluation, we recommend that the 

prospective evaluation capture detailed information on participants’ baseline characteristics 

(including BMI, HbA1c, diabetes duration, and any comorbidities) and measure outcomes at 

similar time points as seen in the Virta Health study. Researchers may also consider measuring 

other baseline characteristics such as motivation or comfortability with technology, as this may 

provide additional information on mediators or moderators of treatment effect. We also

recommend that researchers look for a wide range of data on harms as well as other patientimportant outcomes such as quality of life.
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

34

CONCLUSIONS

While they have important limitations, studies of Virta Health and other virtual diet programs 

suggest that selected populations with type 2 diabetes may lower HbA1c, lose weight, reduce 

medication use, or reverse diabetes after participating in an intensive program based on a 

ketogenic diet or other diets. Due to limitations in study designs, we could not determine whether 

these outcomes were driven by the remote continuous care interventions or by the diets.

Additionally, because studies enrolled participants who were interested in intensive diabetes 

management programs and met other study eligibility criteria, findings may not apply to the 

wider, unselected Veteran population. As Veterans’ preferences for the type of diet they follow 

are likely to vary, a practical solution to improving diabetes care should include testing a variety 

of diet options if the particular diet is not the critical component of the intervention. This type of 

evaluation could inform how Virta Health and other virtual diabetes programs might be adapted 

to meet the needs of a variety of Veterans with type 2 diabetes.
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

35

ACKNOWLEDGMENTS 

This topic was developed in response to a nomination by Steve Pizer, PhD and David Atkins,

MD MPH for the purpose of informing the ongoing VA and Virta Health pilot project

evaluation. The scope was further developed with input from the topic nominators (ie, 

Operational Partners) and the ESP Coordinating Center. 

In designing the study questions and methodology at the outset of this report, the ESP consulted 

several technical and content experts. Broad expertise and perspectives were sought. Divergent 

and conflicting opinions are common and perceived as healthy scientific discourse that results in 

a thoughtful, relevant systematic review. Therefore, in the end, study questions, design, 

methodologic approaches, and/or conclusions do not necessarily represent the views of 

individual technical and content experts. 

The authors gratefully acknowledge Payten Sonnen for her help with data extraction and Julia 

Haskin, MA for her editorial review. The authors also acknowledge the following individuals for 

their contributions to this project: 

Operational Partners

Operational partners are system-level stakeholders who have requested the report to inform 

decision-making. They recommend Technical Expert Panel (TEP) participants; assure VA 

relevance; help develop and approve final project scope and timeframe for completion; provide 

feedback on draft report; and provide consultation on strategies for dissemination of the report to 

field and relevant groups.

David Atkins, MD, MPH

Director

Health Services Research and Development

Steve Pizer, PhD

Chief Economist

Partnered Evidence-based Policy Resource Center

VA Boston Healthcare System 

Key Informants

The ESP sought input from 2 Key Informants with expertise in delivering diet education and 

counseling among patients with type 2 diabetes in clinical settings. 

Shannon Hughes, RD CDE

VA Portland Health Care System, Nutrition and Food Service

Portland, OR

Dawn Barnachea, RD CDE

VA Portland Health Care System, Nutrition and Food Service

Portland, OR
Evidence Brief: Virtual Diet Programs for Diabetes Evidence Synthesis Program

36

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