Incentivizing Behavior Change Skills to Promote Weight Loss
Phase: NA
Conditions: Obesity
Sponsor: Duke University

Incentives Research Summary  
3/1/2018 
 
Table 1. Study design 
Incentives 
for interim 
weight 
loss 
Incentives for 
dietary self-
monitoring  
Yes 
No 
Yes 
A 
C 
No 
B 
D 
 
1.  Protocol Title: Incentivizing behavior change skills to promote weight loss 
 
2.  Purpose of the Study:  
 
Aim 1: Determine feasibility of using automated algorithms that analyze dietary 
self-monitoring and interim weight loss data to provide real-time positive 
reinforcement using variable-ratio financial incentives. 
 
Aim 2: Evaluate intervention acceptability, as indicated by recruitment, intervention 
adherence, and outcome measurement rates as well as feedback from qualitative 
interviews. 
 
Aim 3: Estimate cost of delivering the intervention and cost to patients for 
participating in the program.  
 
3.  Background & Significance:  
 
Two-thirds of the United States (US) population is classified as obese or overweight. 
This epidemic has profound negative physical, psychological, and financial 
consequences. Despite the existence of effective behavioral weight loss interventions, 
many people do not achieve adequate weight loss during the intervention period, and 
most people regain lost weight in the year following intervention. Therefore, novel 
methods are needed to improve initial weight loss and promote long-term weight loss 
maintenance. One promising strategy is reinforcement via financial incentives. 
Reinforcement may be negative (removal of a stimulus to increase desired behavior) or 
positive (addition of a reward to increase desired behavior) and may be delivered on a 
fixed-ratio (predictable) or variable-ratio (unpredictable) schedule. Despite theoretical 
and empirical support in other behavioral domains, in the context of weight loss, few 
studies have examined positive reinforcement delivered on a variable-ratio schedule. 
Those few studies involved lotteries or gifts and primarily incented behaviors indirectly 
associated with weight loss (e.g., walking). Thus, more research is needed to evaluate 
the effect of positive reinforcement delivered on a variable-ratio schedule. 
 
A key issue is whether incentives should be provided for weight loss itself or for building 
behavioral skills that support weight loss. Incenting weight loss alone does not ensure 
that important cognitive/behavioral skills (e.g., dietary self-monitoring) will be learned 
because other, less enduring strategies (e.g., extreme caloric restriction) might be 
utilized in the short-term. By the same token, incenting skill-building alone does not 
ensure that sufficient weight loss will be achieved. Therefore, incenting skill-building and 
weight loss may be more effective than incenting either alone. To our knowledge, no 
study has examined this issue.  
 
4.  Design & Procedures: This 2X2 between-subjects factorial 
study involves incentives for dietary self-monitoring (yes vs. no) 
and/or interim weight loss (yes vs. no) (Table 1).  
Three cohorts of 40 overweight/obese patients (10 randomized 
to each condition in each cohort) will be enrolled (total n=120). In 
each cohort, four dietary groups will be created, one 
corresponding to each of the four study conditions. These patients will participate in a 
24-week weight loss program involving a low-carbohydrate diet protocol that is delivered 

Incentives Research Summary  
3/1/2018 
 
in person every 2 weeks.  Participants will be instructed to record their daily dietary and 
liquid intake on a mobile telephone dietary application (app) and weigh themselves daily 
at home on a study-provided cellular scale. We will develop an innovative information 
technology (IT) solution that will collate dietary self-monitoring data, input by patients via 
an app, and interim weight loss data, obtained from the cellular scale. Using these data, 
an algorithm will classify participants weekly as achieving adequate dietary self-
monitoring and/or interim weight loss to earn unpredictable, intermittent cash rewards. 
Notice of reward will be provided via text message, and credit will be uploaded to a Duke 
ClinCard in real-time.  
 
5.  Selection of Subjects: Inclusion criteria are listed in Table 2. 
 
Table 2. Inclusion and exclusion criteria 
Inclusion criteria determined by telephone  
 aged 18-70 years 
 self-reported BMI ≥ 29 kg/m2 (to allow 
for error; final criterion will be BMI ≥ 30 
kg/m2) 
 desire to lose weight 
 agree to attend visits per protocol 
 access to telephone and reliable 
transportation 
 no errors on a validated 6-item cognitive 
screener1  
 able to complete study measures 
 English speaking 
 smart phone with data and texting plan 
Exclusion criteria determined by telephone 
 dementia, psychiatric illness, or substance 
abuse that might interfere with the 
intervention 
 weight loss ≥ 4.5 kg in the month prior to 
screening  
 enrollment in a research study focusing on 
weight loss or health behavior change 
 residing in a nursing home or receiving 
home health care 
 impaired hearing 
 medication other than metformin, incretin 
mimetics and incretin enhancers for type 2 
diabetes due to increased risk for 
hypoglycemia 
 
 unable to attend sessions at the four 
scheduled times 
 unstable heart disease in the 3 months 
prior to screening:  
o having Acute coronary syndrome 
(ACS) including STEMI (ST-
elevation myocardial infarction),  
NSTEMI (non-ST elevation 
myocardial infarction) and 
unstable angina (UA)  
o recent coronary 
revascularization [recent 
coronary bypass grafting 
(CABG) or percutaneous 
coronary intervention (PCI) 
o unstable arrhythmia 
(supraventricular tachycardia, 
ventricular tachycardia, 
ventricular fibrillation) 
o recent acute congestive heart 
failure exacerbation [requiring 
increased doses of oral or 

Incentives Research Summary  
3/1/2018 
 
intravenous (IV) diuretics or 
hospitalization] 
 furosemide ≥40 mg or equivalent 
 chronic kidney disease at stage 3 or 
higher 
 Weight > 380 lb 
Inclusion criteria determined in person  
 stable health by medical history  
 BMI ≥ 30 kg/m2 
Exclusion criteria determined in person  
 
blood pressure ≥ 160/100 mmHg 
 pregnancy (determined by urine 
pregnancy test) pregnancy, breastfeeding, 
or lack of birth control if premenopausal 
 
Weight > 380 lb 
 
Subject Recruitment & Compensation: Initially, we will recruit from the Durham 
community via flyers, paid advertisements, Research Match and social media. If we do 
not achieve sufficient enrollment for the first cohort, then we will obtain referrals from 
Duke Primary Care physicians and targeted recruitment via electronic health record 
screening and recruitment letters/calls. We will wait approximately 10 days after mailing 
the recruitment letter and then call patients to assess interest and eligibility. As part of 
the intervention, some participants will receive financial incentives (section 8). All 
participants may choose to receive $25 for week-24 outcome visits or keep their scale in 
lieu of the $25. Anyone who participates in a qualitative interview will receive an 
additional $25. 
 
6.  Consent Process – see Section 14 of the e-IRB submission form and complete the 
questions in that section.   
 
7.  Subject’s Capacity to Give Legally Effective Consent: Ability to give consent will 
be assessed in the recruitment call and in-person visit. We will not enroll participants 
unable to provide consent.  
 
8.  Study Interventions: In this study, overweight/obese outpatients will participate in a 
24-week weight loss program involving either a low-carbohydrate diet (LCD) or low-
fat/low-calorie diet (LFD) protocol, which will be delivered in person every 2 weeks. 
Participants in each condition A-D will meet in a separate group. In cohort 1, we used 
the LCD because reviews have indicated that short-term weight loss (6 months) is 
greater with LCD than with LFD. Furthermore, to our knowledge, every financial 
incentive study has used the more common LFD approach, making use of the LCD 
innovative. As we conducted cohort 1, we realized that there was a mismatch between 
the dietary self-monitoring that we are encouraging and the LCD. That is, although 
people on the LCD would normally be encouraged to monitor their carbohydrate intake, 
the app that we are using, MyFitnessPal, readily displays calories rather than 
carbohydrates. Furthermore, in the LCD, participants focus less on portion control as 
portions are not restricted for some foods. Yet, accurate accounting of dietary intake via 
an app requires knowledge of portion sizes for all foods, even those that are 
carbohydrate-free. Finally, one criterion for earning a financial incentive each week is to 
eat a minimal amount of calories (1000 for females, 1200 for males), encouraging 
participants to self-monitor their food intake. We use a lower calorie limit to ensure that 
people are eating enough because participants may overly restrict their calorie intake 
because they believe it will increase weight loss. We teach them that they should eat a 

Incentives Research Summary  
3/1/2018 
 
minimum number of calories per day because eating less may be unsafe without closer 
monitoring and is not a long-term, sustainable habit. For all of these reasons, we 
decided to evaluate use of the LFD during cohort 2 to see if it provides a better match for 
the self-monitoring behavior that we are teaching via MyFitnessPal. This type of change 
is consistent with the nature of the R34 mechanism that funds this study. 
 
In cohort 2, we observed lower retention for the primary outcome assessment (81% 
compared to 88% on cohort 1; minimum goal is 80%) and less mean weight loss. These 
differences could be due to two major differences between cohorts 1 and 2: (a) Use of 
the low-fat diet. Dr. Yancy’s previous studies show a slight advantage for the LCD during 
the first 4-6 months; and (b) Our population had different demographics, likely due to 
differences in where we advertised the study. Cohort 2 was more racially diverse and 
lower socioeconomic status. We feel it is important to recruit a more diverse sample to 
enhance external validity. Therefore, for cohort 3, we will use the same recruitment 
methods but return to the LCD to see if we can enhance weight loss. We will also 
make a more concerted effort to discuss the importance of returning for outcome 
assessments at various points in the study. We will also add an extra in-person session 
at week 1 so that we can spend greater time showing participants how to use 
MyFitnessPal at week 0 and have the opportunity to teach participants about portion 
sizes during week 1. We typically have not focused on portion sizes when teaching the 
LCD because portions are not restricted, and people seem to spontaneously reduce 
their calorie intake due to greater satiety.   
 
8a. LCD PROTCOL (cohort 1 & Cohort 3) 
Weight-Loss Intervention. A registered dietitian (RD) will lead all meetings. Upon 
arrival at all meetings, participants will have their weight measured.  After the first 
meeting, participants will have their blood pressure measured at every meeting. Diabetic 
patients will be asked to report any abnormal blood glucose levels by filling out a short 
survey. At the first meeting, participants will create an individualized weight loss goal. 
They will also receive a cellular scale, a lay press diet book (The New Atkins for a New 
You), and education about the initial phase of the diet. This instruction will include a 
review of foods to emphasize and foods to avoid or minimize. Initially, carbohydrate 
intake will be restricted to 20 grams per day. Caloric intake will not be specified, as ad 
libitum instruction in an LCD typically leads to spontaneous calorie reduction.2,3 The diet 
will begin with unlimited amounts of animal foods (meat, chicken, turkey, other fowl, fish, 
shellfish) and eggs, limited amounts of hard cheese, and limited servings of salad and 
low-carbohydrate vegetables. Artificial sweeteners can be used, whereas caffeine and 
alcohol are to be limited. Due to the diuresis that can occur at diet initiation, participants 
will be warned of the symptoms of dehydration and instructed to drink adequate fluids to 
prevent dehydration. A cup of broth daily will be recommended at diet initiation to 
prevent dehydration. Participants will be monitored for hypotension at the group visits. 
Participants will be given contact information for the study physician, who will be on 24-
hour call.  
 
At every meeting, the participants will receive handouts that cover information specific to 
that session’s topic (see table titled ‘Log2Lose Class Descriptions’). The first 15 minutes 
of each meeting will be devoted to practicing behavioral goal-setting using the group-
based goal-setting protocol from our previous weight loss maintenance trial. Participants 
will set 2-week behavioral goals using SMART (specific, measurable, attainable, 
relevant, time-bound) criteria. At each meeting, the group will review goals set at the 
previous meeting, their level of success achieving those goals, and refine their goals. To 

Incentives Research Summary  
3/1/2018 
 
facilitate goal attainment, participants will be instructed to log their daily food intake 
through the MyFitnessPal® dietary app, which contains an extensive food database. To 
prevent fatigue, the software app is designed to facilitate ease of entering foods that are 
most commonly consumed. MyFitnessPal® readily provides detail on calories, although 
information on calorie type (including carbohydrates) is provided within the app as well. 
MyFitnessPal connects with Fitbit®, another mobile app, which sends data to a Duke-run 
system called Prompt.  
 
As a participant’s weight loss approaches half of his/her 24-week weight loss goal, the 
participant will be instructed to add approximately 5 grams to the daily carbohydrate 
intake each week as long as weight loss continues. If the participant maintains weight or 
adds weight, then he/she will return to the daily carbohydrate intake of the previous 
week. Similarly, as the participant approaches goal weight, he/she will add 
approximately 5 grams to the daily carbohydrate intake each week until weight regain 
occurs. At that point, the participant will return to the daily carbohydrate intake from the 
previous week. This will become the maintenance level of carbohydrate intake for the 
individual. Added carbohydrates can be extra servings of salad vegetables, low-
carbohydrate vegetables, avocado, or cheese, or the addition of servings of fruits, nuts, 
or soft cheese. Participants can also choose low-carbohydrate marketed products such 
as snack bars and shakes to satisfy cravings for sweet foods. Patients will be mailed a 
letter 4-8 weeks prior to the end of the study asking them to schedule a final visit with the 
study team following completion of the class  
 
 
Log2Lose Class Descriptions 
(Handouts used) 
Class 
1 
Week 0: Let’s 
Get Started -  
Participants will receive basic 
introductions to the study design, 
opportunities to receive incentives 
throughout the study based on group 
assignment, how to use the cellular 
scale and dietary tracking smartphone 
app, and a quick introduction to the low 
carb diet.   
 
Atkins book 
 
Session weigh-
in log 
Class 
2:  
 
Week 1 –  
Introduction 
to the Low 
Carb Diet & 
Using SMART 
Goals 
We will review basic weight loss 
principles including concepts of energy 
balance and calorie content in 
macronutrients. Participants will learn to 
distinguish high carb foods from low 
carb foods, and learn their initial 
carbohydrate restriction level. We will 
also introduce SMART goal setting, 
teaching participants how to create 
specific behavioral goals at each group 
session.  
 
Introduction to 
Low Carb Diet 
 
  
 
SMART Goal 
Sheets 
Class 
3: 
Week 2- 
Reviewing the 
Low Carb 
Diet, 
Interpreting 
the Food 
Label, 
Participants will learn how to calculate 
net carbs, understand the carbohydrate 
content of different food groups and 
products, and learn how to use the food 
label to help achieve success. A variety 
of class exercises will lead participants 
to understand the meaning of various 
 
Low Carb Quiz 
 
Net Carbs 
 
Interpreting 
Label Claims for 
the Low Carb 
Diet 
 
 

Incentives Research Summary  
3/1/2018 
 
 
types of information on the nutrition 
facts label.   
Class 
4: 
Week 4- 
Troubleshooti
ng Common 
Low Carb 
Questions 
 
This class will address common areas 
of concern for the low carb diet, and will 
allow participants to ask questions and 
share ideas.  Topics will include ketosis, 
brainstorming new meal ideas, how to 
deal with side effects and cravings. We 
will also discuss realistic rates of weight 
loss for the study duration.  
 
Common Pitfalls 
and the Low 
Carb Diet 
Class 
5: 
Week 6 – 
Grocery 
Shopping: 
Stocking a 
Low Carb 
Kitchen 
 
Participants will learn strategies for 
purchasing food in the grocery store 
that is compliant with the low carb diet. 
The instructor will discuss how to select 
options from each section of the grocery 
store, including produce, meat/dairy, 
and specialty grocery items that 
participants may find helpful. Food 
packages/labels will be brought in for 
demonstration.  
 
Low Carb 
Shopping List 
Class 
6: 
Week 8 – 
Restaurant 
Eating: Dining 
Out 
Strategies 
 
Participants will learn how to make 
healthy, low-carb selections when 
dining out in a variety of restaurants. 
Using restaurant menus (a mix of actual 
and hypothetical), participants will work 
to develop meal plans for various types 
of cuisines. Helpful strategies for meal 
modifications and special requests will 
be discussed. Participants will learn 
resources to help them locate the 
nutritional information for restaurant 
foods. 
 
Strategies for 
Low Carb 
Dining 
 
Menu 
Exercise/Activity 
Class 
7: 
Week 10 – 
Modifying 
your Recipes: 
Low Carb 
Cooking  
 
This class will feature a discussion of 
low carb cooking techniques, as well as 
a video that highlights several low carb 
recipes. Participants will learn how to 
modify recipes to be lower in 
carbohydrates, using different 
ingredients and cooking/preparation 
techniques.  Participants will be led 
through an interactive exercise where 
they will try their hand at modifying 
recipes. Participants will be introduced 
to various web sites and other 
resources for finding healthy, low-carb 
recipes. 
 
Eazy Cookin’ 
Low Carb 
Cooking Video 
Recipes 
 
Low Carb 
Resources 
Note* We will be showing participants a cooking video and providing recipes for them to 
take home and try.  The name of the video is "Eazy Cookin: Low Carb, Volume 1" by 
Chef Robert van Houten.  We will be playing this 35 minute video in the classroom using 
a laptop and projector, and the purpose is to demonstrate cooking techniques described 
in our classes, and to provide meal examples that are appropriate for the diet.  

Incentives Research Summary  
3/1/2018 
 
Class 
8: 
Week 12 – 
Sharing Your 
Success, and 
Phasing in 
Additional 
Carbohydrate
s 
This class is designed to allow 
participants the opportunity to share 
their success: new recipes, food 
products, behavioral habits or strategies 
that have helped with their success on 
the low carb diet.  At the halfway point 
in the study, this week is also a time to 
discuss when and how to increase 
carbohydrate intake, providing 
individual guidance for participants. 
 
Sharing Your 
Success 
 
Introducing 
Carbs Back into 
Your Diet 
Class 
9: 
Week 14 - 
Mindful 
Eating 
 
Participants will learn the importance of 
mindful eating for successful weight 
loss. They will learn how to distinguish 
mindful versus mindless eating 
behaviors and develop strategies to 
deal with the latter. A class exercise will 
be conducted to demonstrate mindful 
eating 
 
Mindful Eating 
 
Mindful Eating 
Exercises / 
Activities 
Class 
10: 
Week 16 – 
Physical 
Activity & 
Weight Loss 
 
Participants will learn the difference 
between physical activity and exercise, 
as well as the health benefits of 
physical activity and general 
recommendations.  As a group, 
participants will brainstorm and plan for 
realistic ways to incorporate more 
activity into their daily life.  
 
Physical Activity 
Guidelines 
 
Infographic of 
“Taking Breaks” 
Class 
11: 
Week 18 – 
Planning for 
High-Risk 
Situations 
 
This class will discuss various types of 
high-risk situations that can act as 
obstacles to successful weight loss 
using a low carb diet.  These situations 
can be emotional or social, and may 
differ for each participant.  We will 
review common high-risk situations, and 
discuss strategies, such as planning 
ahead, so that these situations do not 
lead to lapses and weight gain. 
Worksheets will be provided so 
participants can develop individual 
plans.  
 
Planning for 
High-Risk 
Situations 
Class 
12: 
Week 20 – 
How to Build 
Your Support 
Network 
 
This class will discuss different forms of 
support needed during weight loss, 
such as the social support found in 
group sessions, individual support 
persons (spouse/partner, exercise 
buddy, health care provider), as well as 
how technology can be used to support.  
Participants will also review different 
support strategies (encouragement, co-
participation, etc.), and reflect and what 
best suits their needs.  
 
Enlisting 
Support 

Incentives Research Summary  
3/1/2018 
 
Class 
13: 
Week 22 – 
Success for 
Long-term 
Weight Loss 
Maintenance 
 
This class will review important 
strategies for long-term weight 
management, including the more liberal 
phase of the low carb diet using a 
carbohydrate threshold.  Participants 
will also learn the importance of regular 
increase physical activity to combat a 
reduced metabolic rate after weight 
loss. In addition to emphasizing self-
monitoring behaviors long-term, 
previous class topics will be reviewed: 
planning ahead for high-risk situations 
and enlisting helpful social support.  
 
Habits of Highly 
Successful 
Losers 
 
National Weight 
Control Registry 
Class 
14: 
Week 24 – 
Graduation 
and Low Carb 
Potluck with 
recipe 
exchange 
Participants will end the program with a 
celebration of their success. 
Participants will have the opportunity to 
take part in a low carb potluck complete 
with recipes to take home. Study 
personnel will also ask for feedback 
regarding the content and structure of 
the group sessions.  
 
 
8b. LFD PROTOCOL (cohort 2) 
Weight-Loss Intervention: A Registered Dietitian (RD) will lead all meetings. Upon arrival 
at all meetings, participants will have their weight measured. Patients with diabetes will 
be asked to report any abnormal blood glucose levels by filling out a short survey. At the 
first meeting, participants will create an individualized weight loss goal. They will also 
receive a cellular scale, a lay press diet book (The American Heart Association No-Fad 
Diet) and education about the diet. Participants will be given contact information of the 
study physician, who will be on 24-hour call.  
This diet will restrict total fat intake to less than 30% of daily energy intake and saturated 
fat to less than 10% of daily energy intake. The diet will consist mainly of complex 
starches (e.g., whole grain bread, pasta, rice), vegetables, fruits, lean meats (e.g., 
poultry and fish), and low-fat dairy products. In keeping with research showing that 
whole grain sources of carbohydrates are healthier than refined carbohydrates in regard 
to CHD risk, we will emphasize whole grain foods. In addition, we will emphasize the 
intake of vegetable oils (e.g., olive and canola oils) that contain high proportions of 
mono- and polyunsaturated fats rather than solid oils that contain trans fats (e.g., 
shortening).  
The goal for total caloric intake will be calculated by subtracting 500 calories per day 
from the maintenance energy requirement for each individual. In order to determine 
maintenance energy requirement, resting metabolic rate (RMR) will be calculated using 
the Mifflin-St Jeor formula. This formula was selected because it has been shown to be 
more accurate than other equations in estimating RMR for obese individuals. The RMR 
result will then be multiplied by an activity factor corresponding to an individual’s activity 
level in order to determine maintenance energy needs (age is in years, weight is in 
kilograms, height is in centimeters.) 

Incentives Research Summary  
3/1/2018 
 
Women : Maintenance energy intake = [9.99 x actual weight + 6.25 x height – 4.92 x age 
– 161]  
x Activity Factor [1.2=Sedentary; 1.4=Low Active to Moderate; 1.6=Active]  
Men: Maintenance energy intake = [9.99 x actual weight + 6.25 x height – 4.92 x age +5] 
x Activity Factor [1.2=Sedentary; 1.4=Low Active to Moderate; 1.6=Active]  
At every meeting, the participants will receive handouts that cover information specific to 
that session’s topic (see table titled ‘Log2Lose Low-Fat Class Descriptions’). The first 15 
minutes of each meeting will be devoted to practicing behavioral goal-setting using the 
group-based goal-setting protocol described above. At each meeting, the group will 
review goals set at the previous meeting, their level of success achieving those goals, 
and refine their goals. To facilitate goal attainment, participants will be instructed to log 
their daily food intake through the MyFitnessPal® dietary app, which contains an 
extensive food database. MyFitnessPal® provides detail on calories and macronutrients. 
MyFitnessPal® connects with FitBit®, another mobile app, which sends data to a Duke-
run system called prompt.  
Group counseling will focus on the selection of desirable types and portions of foods, 
interpretation of food labels, common pitfalls, and behavioral modifications to reduce 
cravings. If a participant experiences a prolonged plateau after a previous downward 
weight trajectory, then energy intake may be reduced further by 300-500 kcal per day. If 
a participant achieves goal weight before the end of the 24-week period, energy intake 
will be adjusted to maintenance-level calories.  
Log2Lose Low Fat Class Descriptions 
(Handouts 
used) 
Class 
1: 
Week 0 – Let’s Get 
Started:  Introduction 
to the Low Fat Diet 
Participants will receive basic 
introductions to the study design, 
opportunities to receive incentives 
throughout the study based on group 
assignment, how to use the cellular scale 
and dietary tracking smartphone app, 
and a quick introduction to the low fat 
diet.  
Participants will also receive their 
personalized calorie and fat gram 
allowance. The serving size for each of 
the different food groups will be 
discussed. Participants will learn to 
distinguish high fat foods from low fat 
foods. 
 
Session 
weigh-in 
log 
 
Calorie/
Fat 
Budgets 
 
Low-Fat 
Diet 
Quiz 
 
Class 
2: 
Week 2 – Interpreting 
the Food / Nutrition 
Label 
Participants will learn how to interpret a 
nutrition facts label. This class will go will 
address more detailed areas of nutrition 
including different types of fat, 
cholesterol, fiber, sugar, protein, and 
vitamins and minerals. A variety of class 
exercises will lead participants to 
understand the meaning of various types 
 
Label 
Reading 
 
Underst
anding 
Label 
Claims 
 
Practice 
Food 

Incentives Research Summary  
3/1/2018 
 
of information on the nutrition facts label. 
 
Labels 
 
Class 
3: 
Week 4 – Energy 
Balance:  Tracking 
Diet & Activity 
Participants will learn the concept of 
energy balance, and the importance of 
accurate tracking for calories consumed 
(dietary intake) and calories burned 
(physical activity).  They will participate 
in an exercise showing the need for 
measuring portions with regards to 
accurate tracking.  The dietary mobile 
app will be reviewed, including shortcuts 
and tips to make tracking easier and 
more convenient.  
 
Track 
Your 
Food 
 
Track 
Your 
Activity 
Class 
4: 
Week 6 – Dining Out 
Strategies 
Participants will learn how to make 
healthy, low-fat selection when dining out 
in a variety of restaurants. Using actual 
restaurant menus, participants will work 
in team to develop meal plans for various 
types of cuisines. Participants will learn 
resources to help them locate the 
nutritional information for restaurant 
foods. 
 
 
Strategie
s for 
Dining 
Out 
 
Strategie
s for 
Fast 
Food 
Eating 
 
Menu 
Exercise 
Class 
5: 
Week 8 – Grocery 
Shopping: Stocking a 
Healthy Kitchen 
Participants will learn strategies for 
purchasing healthy food in the grocery 
store. The instructor will discuss how to 
select produce, meat, grains, dairy and 
condiments that are in line with their 
dietary goals. Common questions will 
also be answered regarding the benefits 
of eating seasonally and when to buy 
organic.  
 
Grocery 
Staples 
List 
 
NC 
Seasona
l 
Produce 
 
Pesticid
es in 
Produce 
 
Class 
6: 
Week 10 – Low Fat 
Cooking 101 
Participants will view cooking videos that 
will review the basic kitchen tools one 
needs to have in the kitchen for low fat 
cooking along with a series of healthy 
recipes to prepare at home. Participants 
will have an opportunity to ask questions 
about healthy food preparation. 
Participants will be introduced to various 
web sites and other resources for finding 
healthy, low-fat recipes. 
 
Cooking 
Tips for 
Weight 
Manage
ment 
 
Handout
& Video: 
Integrati
ve 
Nutrition 
Healthy 
Cooking 
Note* We will be showing participants a cooking video and providing recipes for them to 
take home and try.  The name of the video is "Healthy Cooking" by Integrative Nutrition.  
We will be playing this 50 minute DVD in the classroom using a laptop and projector, 
and the purpose is to demonstrate cooking techniques described in our classes, and to 

Incentives Research Summary  
3/1/2018 
 
provide meal examples that are appropriate for the diet. 
Class 
7: 
Week 12 – Modifying 
Your Recipes 
Participants will learn how to modify 
recipes to be lower in calories, fat, 
sodium and sugar as well as way to 
increase nutrients such as vitamins, 
minerals and fiber. Several class 
exercises will demonstrate how to take a 
high fat recipe and modify multiple 
ingredients to improve its nutritional 
profile. Participants will be led through an 
interactive exercise where they will try 
their hand at modifying recipes. 
 
Recipe 
Makeov
ers: 5 
Simple 
Steps to 
Healthier 
Meals 
 
Low-Fat 
Substitut
ions 
 
Class 
Exercise
: recipe 
makeov
ers 
Class 
8: 
Week 14 - Mindful 
Eating 
 
Participants will learn the importance of 
mindful eating for successful weight loss. 
They will learn how to distinguish mindful 
versus mindless eating behaviors and 
develop strategies to deal with the latter. 
A class exercise will be conducted to 
demonstrate mindful eating 
 
Mindful 
Eating 
 
Mindful 
Eating 
Exercises / 
Activities 
Class 
9: 
Week 16 – Physical 
Activity & Weight Loss 
Participants will learn the difference 
between physical activity and exercise, 
as well as the health benefits of physical 
activity and general recommendations.  
As a group, participants will brainstorm 
and plan for realistic ways to incorporate 
more activity into their daily life. 
 
Physical 
Activity 
Guidelines 
 
Infographic 
of “Taking 
Breaks” 
Class 
10: 
Week 18 – Planning 
for High-Risk 
Situations 
This class will discuss various types of 
high-risk situations that can act as 
obstacles to successful weight loss using 
a low fat diet.  These situations can be 
emotional or social, and may differ for 
each participant.  We will review 
common high-risk situations, and discuss 
strategies, such as planning ahead, so 
that these situations do not lead to 
lapses and weight gain. Worksheets will 
be provided so participants can develop 
individual plans. 
 
Preventing 
Relapse 
Class 
11: 
Week 20 – How to 
Build Your Support 
Network 
 
This class will discuss different forms of 
support needed during weight loss, such 
as the social support found in group 
sessions, individual support persons 
(spouse/partner, exercise buddy, health 
care provider), as well as how 
technology can be used to support.  
Participants will also review different 
support strategies (encouragement, co-
 
Enlisting 
Support 

Incentives Research Summary  
3/1/2018 
 
participation, etc.), and reflect and what 
best suits their needs. 
Class 
12: 
Week 22 – Success for 
Long-term Weight 
Loss Maintenance 
 
This class will review important 
strategies for long-term weight 
management.  Participants will also learn 
the importance of regular increase 
physical activity to combat a reduced 
metabolic rate after weight loss. In 
addition to emphasizing self-monitoring 
behaviors long-term, previous class 
topics will be reviewed: planning ahead 
for high-risk situations and enlisting 
helpful social support. 
 
Habits of 
Highly 
Successful 
Losers 
 
National 
Weight 
Control 
Registry 
Class 
13: 
Week 24 – Graduation 
and Low Fat Potluck 
with recipe exchange 
Participants will end the program with a 
celebration of their success. Participants 
will have the opportunity to take part in a 
low fat potluck complete with recipes to 
take home. Study personnel will also ask 
for feedback regarding the content and 
structure of the group sessions. 
 
  
 
 
 
Incentive Structure. Table 3 shows the incentive schedule for each cell of the 2X2, 
which is informed by several learning theory principles. First, as previously discussed, 
we are using a variable-ratio incentive schedule, whereby the timing and amount of 
incentive will be unknown to participants. Second, the expected value (i.e., maximum 
that participants can earn) is the same in all conditions so that any advantage seen in 
the combined condition (A) cannot be attributed to patients having a larger expected 
value. Thus, the amount that condition (A) receives for self-monitoring is half of what 
condition (B) receives for dietary self-monitoring, and the amount that (A) receives for 
interim weight loss is half of what condition (C) receives for interim weight loss; however, 
the payment schedules are the same for conditions (A) and (B) for dietary self-
monitoring and for conditions (A) and (C) for interim weight loss. Third, participants will 
be eligible to receive incentives every week during the first 4 weeks because learning of 
new behaviors is higher with initial continuous reinforcement. For Cohorts 1 & 2, 
Intermittent reinforcement will occur later in the schedule due to its beneficial impact on 
maintenance of behaviors. For Cohort 3, they will be eligible for incentives every week of 
the study, and intermittent payment will mean varying amounts of incentives each week. 
Further, the payment for dietary self-monitoring and weight loss is the same throughout 
the study so that the incentives do not have differential effects on motivation of dietary 
self-monitoring and interim weight loss. Fourth, patients in all conditions will be eligible 
for incentives during the same weeks so that any differential effects between conditions 
cannot be attributed to different reinforcement schedules (e.g., getting paid nearly every 
week or every week in combined condition A).  
 
No study has defined the optimal amount of incentive for various reinforcement 
schedules. We selected an expected value of $300 per participant based on provider 

Incentives Research Summary  
3/1/2018 
 
pay for performance studies, in which providers receive incentives equivalent to 1-3% of 
their income for optimal clinic performance.4,5 Our study population very likely will 
comprise patients of lower socioeconomic status. We expect that 1% of the median 
annual per capita income for a single person in Durham, NC (~$30,000),6 and the 
absolute value of $300, will be perceived as significant by patients given their relatively 
low median income and the diminishing marginal utility of income (i.e., $300 provides 
more utility to a lower-income person than a higher-income person).7 Based on feedback 
from participants in cohorts 1 & 2 – cohort 3 may receive up to $322. Instead of receiving 
$0 for achieving a goal on the reinforcement schedule, participants will receive $2. This 
will increase the maximum potential incentive to $322. 
 
All participants will receive a Duke ClinCard card during the first group session that they 
attend. In all conditions, participants will be told that they will receive the payment for the 
outcome assessment visit via a credit to the Duke ClinCard. In conditions A-C, 
participants will be told that they may receive credits to the card at various times during 
the study for using the dietary app (A and B) or achieving weight loss (A and C). We 
chose this incentive type and delivery method instead of providing payment at the group 
sessions so as not to delay reward and to avoid the confound of requiring attendance to 
receive the award. Participants will not be informed of the reward schedule or the 
incentive amounts.  
 
Instruction to self-monitor dietary intake and self-weigh will be the same across 
conditions. All participants will be urged to enter everything that they eat and drink in the 
app. In conditions A and B, the criterion for reinforcement of dietary self-monitoring is 
that patients must log at least two entries per day and a minimum number of calories per 
day for at least 5 days per week (one of which must be a weekend day). We are allowing 
up to 2 days of inadequate self-monitoring to allow for barriers such as an uncharged 
cell phone battery, being somewhere without the phone, etc. We are only requiring two 
entries per day because some individuals only eat two larger meals per day (although 
some people only eat once daily, our dietitian advises participants not to do this). Males 
must log at least 1200 calories, and females must log 1000 calories. We chose a daily 
caloric criterion because (1) carbohydrate intake may increase over time as patients 
achieve their weight loss goal, so caloric intake is more appropriate than carbohydrate 
intake. Moreover, caloric deficit is thought to be the mechanism underlying weight loss in 
the LCD as with other diets; (2) in our previous and ongoing studies involving a low-
calorie diet, 1500 and 1200 are the lower limits of what we prescribe for males and 
females, respectively, so these criteria provide some flexibility given that food intake is 
frequently underestimated8; and (3) caloric intake is readily available on the app. 
Participants will be asked to contact the CRC if they are unable to use their phone for 
self-monitoring (e.g., they lose it); these participants will be ineligible to receive 
incentives. Such instances will be logged in our tracking database and inform our future 
R01. 
 
Table 3. Incentive schedule for each study arm cohorts 1 & 2 
 
Condition 
 
Incentive 
for 
Week 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
1
1 
12 
1
3 
14 
15 
1
6 
A 
Interim 
WL 
$1
0 
$1
4 
$1
1 
$1
2 
$
0 
$7 
$
0 
$1
3 
$1
0 
$0 
$
0 
$1
2 
$
0 
$0 
$1
4 
$
0 
Dietary 
SM 
$1
0 
$1
4 
$1
1 
$1
2 
$
0 
$7 
$
0 
$1
3 
$1
0 
$0 
$
0 
$1
2 
$
0 
$0 
$1
4 
$
0 
B 
Dietary 
SM 
$2
0 
$2
8 
$2
2 
$2
4 
$
0 
$1
4 
$
0 
$2
6 
$2
0 
$0 
$
0 
$2
4 
$
0 
$0 
$2
8 
$
0 

Incentives Research Summary  
3/1/2018 
 
C 
Interim 
WL 
$2
0 
$2
8 
$2
2 
$2
4 
$
0 
$1
4 
$
0 
$2
6 
$2
0 
$0 
$
0 
$2
4 
$
0 
$0 
$2
8 
$
0 
D 
Neither 
$0 
$0 
$0 
$0 
$
0 
$0 
$
0 
$0 
$0 
$0 
$
0 
$0 
$
0 
$0 
$0 
$
0 
 
 
 
 
 
 
 
 
 
 
Note. WL=weight loss; 
SM=self-monitoring. 
 
 
 
Table 4. Incentive schedule for each study arm cohorts 3 
 
Cond
ition 
 
Incentiv
e for 
Week 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
13 
14 
15 
A 
Interim 
WL 
$10 
$14 
$11 
$12 
$1 
$7 
$1 
$13 
$10 
$1 
$1 
$12 
$1 
$1 
$14 
Dietary 
SM 
$10 
$14 
$11 
$12 
$1 
$7 
$1 
$13 
$10 
$1 
$1 
$12 
$1 
$1 
$14 
B 
Dietary 
SM 
$20 
$28 
$22 
$24 
$2 
$14 
$2 
$26 
$20 
$2 
$2 
$24 
$2 
$2 
$28 
C 
Interim 
WL 
$20 
$28 
$22 
$24 
$2 
$14 
$2 
$26 
$20 
$2 
$2 
$24 
$2 
$2 
$28 
D 
Neither 
$0 
$0 
$0 
$0 
$0 
$0 
$0 
$0 
$0 
$0 
$0 
$0 
$0 
$0 
$0 
 
 
 
 
 
 
 
 
 
 
 
All participants will also be encouraged to weigh themselves everyday given that 
patients who weigh daily achieve greater initial weight loss and weight loss maintenance 
than those who weigh less frequently.9 In conditions A and C, the criterion for 
reinforcement of interim weight loss is that patients have lost weight. Because greatest 
weight loss would be expected at the end of the week, we will calculate weight loss 
based on the weight provided on Day 7 or the closest date for which data are available. 
We are not rewarding based on individualized weight goals so as to avoid rewarding 
participants with less ambitious goals and to avoid penalizing participants who do not 
achieve their more ambitious goals. Participants could “game” the system by having 
someone else weigh in for them or not putting all of their weight on the scale. Our 
software algorithm detects weight greater than 10% difference and removes them so the 
we have some assurance that a family member or friend is not stepping on the cellular 
 
Conditi
on 
 
Incentive 
for 
Week 
17 
18 
19 
20 
21 
22 
23 
2
4 
A 
Interim WL 
loss 
$1
3 
$0 
$0 
$1
0 
$1
5 
$0 
$9 
$
0 
A 
Dietary SM 
$1
3 
$0 
$0 
$1
0 
$1
5 
$0 
$9 
$
0 
B 
Dietary SM 
$2
6 
$0 
$0 
$2
0 
$3
0 
$0 
$1
8 
$
0 
C 
Interim WL 
$2
6 
$0 
$0 
$2
0 
$3
0 
$0 
$1
8 
$
0 
D 
Neither 
$0 
$0 
$0 
$0 
$0 
$0 
$0 
$
0 
 
Conditi
on 
 
Incentive 
for 
Week 
17 
18 
19 
20 
21 
22 
23 
24 
A 
Interim WL 
loss 
$13 
$1 
$1 
$10 
$15 
$1 
$9 
$1 
A 
Dietary SM 
$13 
$1 
$1 
$10 
$15 
$1 
$9 
$1 
B 
Dietary SM 
$26 
$2 
$2 
$20 
$30 
$2 
$1
8 
$2 
C 
Interim WL 
$26 
$2 
$2 
$20 
$30 
$2 
$1
8 
$2 
D 
Neither 
$0 
$0 
$0 
$0 
$0 
$0 
$0 
$0 

Incentives Research Summary  
3/1/2018 
 
scale. As this is a planning study, we will provide patients with incentives even if their in-
person weights differ from their home weights. We will characterize the extent to which 
in-person weights differ from home weights and use this information to inform our future 
trial.  
 
For dietary self-monitoring and interim weight loss, Day 1 of each week will correspond 
to the day of the participant’s in-person group visit. Because greatest weight loss would 
be expected at the end of the week, we will calculate weight loss based on the weight 
provided on Day 7 or the closest date for which data are available. For those weeks 
when an incentive is scheduled, patients who achieve the incentive criterion will receive 
a text message on Day 1 of the following week informing them that they have earned an 
incentive for the previous week’s success and encouraging them to continue their 
efforts. The incentive will be credited to the Duke ClinCard as soon as possible after the 
text has been delivered (timing depends on availability of Duke staff who process 
payments). Patients who do not meet the criterion for reward will receive a text message 
informing them of the missed incentive and encouraging them to self-monitor and weigh 
daily to maximize loss aversion (i.e., the preference to avoid losses). We will program 
the software with algorithms to automatically analyze the dietary and weight data 
according to the aforementioned criteria. Pre-developed targeted text messages will be 
automatically delivered to participants with incentive information accordingly. 
 
Participants who are eligible for a reward in a particular week will receive the following 
message: “Great job on (logging your food or losing weight) this week! $x will be added 
to your gift card. Keep up the good work!” Participants who are ineligible for a reward in 
a particular week will receive the following message: “You did not log your food or lose 
weight enough this week. If you had, you would have earned $(xx). Please log your food 
and lose weight for a chance to earn money.” The message to ineligible participants 
emphasizes loss to enhance loss aversion. These messages are 160 characters or less 
so that they appear in a single message instead of breaking into 2 messages.  
 
Participants will also receive text messages before the group sessions as a reminder to 
attend. Study staff will also communicate with participants via text message if there is a 
cancellation or rescheduling of class. The text messages will indicate that participants 
should call the study team with questions rather than responding to the text message. 
 
In order to send and receive text messages, we will use a software engine designed by 
Duke software engineers, called Prompt. Prompt uses Twilio, Heroku, and Amazon S3. 
Prompt will receive diet data that participants log into the MyFitnessPal app (that is 
connected with the Fitbit API) as well as weight data when they step on the BodyTrace 
scale. We will not collect names in this database; instead, we will only collect phone 
number and study ID of each participant, as well as data from MyFitnessPal (via the 
Fitbit API) (diet tracking information) and from BodyTrace (weights). The data will be 
automatically analyzed weekly according to algorithms we embed. Study staff will login 
to a password-protected database to view study ID and see a list of participants who met 
study criteria for the incentives each week, as well as the incentive amount. We will use 
Twilio to send text messages to participants each week. We will use Heroku to process 
data analysis for the engine. We will use Amazon S3 to store data; data will be 
encrypted when it is stored.  These are companies outside of Duke that will have access 
to participants’ personal information, including name, phone number, and data from 
MyFitnessPal and Fitbit. If these data are further disclosed by them or their business 
partners, it may no longer be covered under the privacy protections. Text messaging 

Incentives Research Summary  
3/1/2018 
 
does not provide a completely secure and confidential means of communication. 
Participants are made aware of the risks that are inherent in using consumer-based 
products such as MyFitnessPal® and Fitbit® (see Human Subjects document).  
 
Survey data will be collected and stored in RedCap. All other data are stored on a 
Heroku server run by software engineers at Duke University Medical Center.  
 
We developed a new scale to assess group factors that may impact weight loss in group 
members. This scale was developed from research-based, theoretical, and anecdotal 
constructs. The scale is composed of 28 items assessing 11 constructs: 
responsibility/accountability, attraction to the group-task, attraction to the group- social, 
instilling hope, observational learning, guidance, reliable alliance, normalizing, social 
support, attachment/cohesiveness, and counter-productivity. The scale will be 
administered on paper to participants prior to group sessions at weeks 2, 12, and 22. If 
participants miss any of these group sessions, we will give it to them at the next group 
session (weeks 4, 14 and 24).   
 
Qualitative Interviews. Participants from each of the 4 conditions will participate in a 
qualitative interview within three weeks by telephone with Dr. Voils at the University of 
Wisconsin-Madison. Within each condition, we will attempt to recruit 5 participants who 
achieved 5% weight loss (minimum clinically significant) and 5 who did not (total n=40) 
so that we can obtain perspectives from those who were more versus less successful. 
Based on our experience, this sample size will be sufficient for evaluating feasibility and 
acceptability of the intervention and obtaining feedback on key issues. The interviews 
will be highly structured and conducted following a script, as in Dr. Voils’ previous pilot 
intervention studies.10 The script will include questions around usability of the dietary app 
and scale, barriers to self-monitoring and weighing, and financial incentive amount and 
delivery. All interviews will be recorded and then transcribed. The interview data will be 
content-analyzed,11 organized around the categories that are covered by the interview 
script. 
 
Outside Key Personnel. Dr. Voils from the University of Wisconsin-Madison leads the 
behavioral science aspects of this study. These responsibilities include the design, 
management, and coordination of the weight loss trial, qualitative interviews, and 
respective data analyses. Dr. Voils co-leads manuscript writing, dissemination of 
findings, and development of future grants. 
 
9. Risk/Benefit Assessment: There are few potential risks associated with any of the 
measures or data to be collected. There are small risks of injury or heart problems due 
to increased participation in physical activity. The threat of this potential problem will be 
reduced by screening for contraindications to physical activity participation and by 
providing proper instruction regarding methods for engaging in physical activity safely, 
as well as contraindications for continuing physical activity. Because the main physical 
activity to be stressed is increased walking, we do not anticipate that the health risks will 
be over and above the risks normally associated with daily walking. Participants may feel 
uncomfortable talking about their experience in the intervention during the qualitative 
interviews. Participants do not have to answer any question that they do not wish to 
answer, as will be explained during the consent process. 
 
 

Incentives Research Summary  
3/1/2018 
 
10. Costs to the Subject: There will be no direct cost to subjects.  If participants 
currently have restriction on the number of text messages or data, they may incur 
cell phone charges (text messaging or data charges) as a result of being in this 
study. 
 
 
11. Data Analysis & Statistical Considerations: Aim 1: Determine feasibility of using 
automated algorithms that analyze dietary self-monitoring and interim weight loss data to 
provide real-time positive reinforcement using variable-ratio financial incentives. 
 
We will develop the incentive algorithms and programming that analyze the dietary and 
self-monitoring data from the mobile diet app. The algorithms and programming will elicit 
an automated trigger to send a text message with content based upon the incentive 
thresholds. We will then embed them into the IT platform and perform quality assurance 
testing to determine that the algorithms appropriately recognize when self-monitoring 
occurs and trigger the correct text message response. At study completion, we will use 
descriptive statistics to describe the number of “data pulls” from the diet app on 
participants’ mobile phones and the percentage of text messages that are successfully 
transmitted back to participants. Furthermore, our project coordinator will maintain logs 
of the technical assistance they provide to participants regarding the diet app and receipt 
of the incentive messages. This will allow us to determine how many times we were able 
to successfully pull in the dietary and self-monitoring data from participants’ telephones 
and to understand and address technical challenges and barriers.  
 
Aim 2: Evaluate intervention acceptability, as indicated by recruitment, 
intervention adherence, and outcome measurement rates as well as feedback 
from qualitative interviews. 
 
Key acceptability information includes rates of recruitment, intervention attendance, and 
retention for outcome assessment visits. The total number of patients screened by 
telephone and in person and reasons for nonparticipation will be recorded in our tracking 
database. The recruitment rate will be calculated for each cohort (the appropriate 
formula will be used for passive vs. active recruitment strategies). We will compare 
recruitment rates across cohorts, particularly if we have to implement additional 
recruitment strategies during the study. The outcome assessment retention rate will be 
calculated for each cohort as [#of participants who return for each outcome 
assessment/number who were eligible upon completion of the baseline assessment]. 
 
One aspect of intervention adherence is attendance at the in-person sessions, which will 
be calculated as [# of participants who attended each in-person session/number who 
were eligible upon completion of the baseline assessment]. Another aspect of 
intervention adherence is the extent to which participants engage in dietary self-
monitoring using the app and self-weighing using their wireless scales. Each week, the 
platform will create a variable indicating whether each participant met criteria for the 
reward. This variable will be plotted longitudinally by study condition so that we can 
examine trends. For example, we will examine whether participants who were incented 
for dietary self-monitoring achieved adequate self-monitoring compared to participants 
who were not incented for doing so, and whether this effect was present throughout the 
study or, for example, just in the first few weeks. We will also examine for each week the 
proportion of days on which adequate dietary self-monitoring was obtained. 
 

Incentives Research Summary  
3/1/2018 
 
Other acceptability information includes consistency between home-based weights 
obtained by the platform and weights obtained at the in-person sessions. We will 
characterize discrepancies between study-based weights and home-based weights 
performed on the same day. If study-based weights are >2.5 lbs greater than home-
based weights, then we will follow up with participants in a nonjudgmental manner to 
understand the nature of the discrepancy.  
 
Aim 3: Estimate cost of delivering the intervention and cost to patients for 
participating in the program.  
 
We will assess the complete set of costs related to each of the four conditions and then 
estimate the incremental costs for the three incentive arms relative to the costs 
associated with condition D (Table 3) that lacks incentives for dietary self-monitoring or 
interim weight loss. To complete cost assessment across the four conditions, we will 
partition costs into labor and capital costs. Labor costs include time spent by the 
registered dietician (RD) leading biweekly group meetings in each condition and time 
spent by the project coordinator providing incentives for dietary self-monitoring or interim 
weight loss. The time spent by these individuals on these activities will be tracked in time 
logs that they complete during the first week of every month of the study. This time log 
will track the time needed by the RD and the coordinator to complete major research and 
non-research tasks so that research time costs can be excluded. RD and coordinator 
cost per hour will be based upon his/her annual compensation (salary+benefits) for full-
time employment. We will not estimate cost of delivering the group-based intervention 
because this is constant across the four study conditions. Capital costs include the 
financial incentives (via Duke ClinCard) provided to each patient in the 3 arms 
(maximum of $300 per patient), overhead costs, office space, telephone service, text 
messaging, and administrative costs (i.e., monthly fees) associated with providing the 
Duke ClinCards. Costs associated with developing and refining the Prompt engine will 
not be included in the cost estimate because we will assume that costs to modify the 
software will be trivial upon scaling in the future trial. 
 
Once the complete set of costs for each of the four conditions is computed for all 
patients, we will estimate arm-specific average costs and compare the incremental costs 
of the three incentive conditions (A-C from Table 3) compared to condition D that lacks 
incentives for dietary self-monitoring or interim weight loss.  These incremental costs will 
be largely driven by differences in incentive costs, monthly fees for the Duke Clincards, 
and project coordinator time spent providing incentives to patients because the RD time 
spent conducting the group meetings are expected to be the same across all four arms 
(unless group attendance in condition D drops markedly over time). These incremental 
cost estimates will inform incremental cost-effectiveness analyses to be conducted in the 
future large-scale trial. Finally, we will assess patient costs for intervention participation, 
which will include the time they spend traveling to and from the group meetings, time 
spent with the group during the intervention, and time spent entering data into the app. 
The cost of patient time spent engaged in the group meetings will be based on patient 
survey data about their annual salary and work hours to compute an hourly wage. In 
cases in which participants are unwilling to provide their income, we will impute based 
on regional salary estimates. 
 
12. Data & Safety Monitoring: This is a minimal risk study so the potential for serious 
adverse events related to the study is low--the intervention consists of diet and physical 
activity recommendations derived from widely-disseminated guidelines that are directed 
to the general population. 

Incentives Research Summary  
3/1/2018 
 
 
In protocol adequacy of protection from risks: 
Additionally, a Data Monitoring Committee (DMC) consisting of the study statistician and 
two additional members (at least one will be a physician with experience in diabetes care 
and at least one will have research experience) who are independent of the study team, 
will review the clinical data routinely with safety as its primary objective.  A study 
physician will be on call at all times. Hypoglycemic events, for patients who may have 
diabetes, and other clinical adverse effects will be recorded at each visit using 
standardized, self-administered forms. All adverse events will be reported to the IRB 
according to local IRB requirements. The DMC will also review adverse events, 
screening, enrollment, and data collection reports at each study meeting to maximize the 
efficiency of recruitment and the validity of the data. Meeting frequency will be 
determined by the members of the DMC but will occur at least yearly. 
 
In data and safety monitoring: 
All research material obtained from participants will be gathered prospectively and will 
include anthropometric, vital sign measurements and participants’ responses to 
questionnaires. Serious (i.e., life-threatening, hospitalization, persistent disability) and 
unanticipated adverse events will be assessed at every visit using standardized 
questions. Anticipated adverse events and side effects for weight-reducing diets and/or 
medication intensification will also be collected at every visit. These may include 
hypoglycemia, hypotension, gallbladder disease, headache, weakness, muscle cramps, 
constipation, diarrhea, and dehydration. Many of these effects related to dietary change 
are transient or easily treated, and can be prevented with adequate hydration, which will 
be emphasized in the dietary counseling. A study physician will be on call at all times to 
manage any adverse events felt to be related to the study. Patients with adverse events 
that are not related to the study will be referred to appropriate health care sources. All 
adverse events will be reported to the IRB according to local IRB requirements and 
reviewed regularly by the study DMC.   
 
In other adverse effects: 
Serious adverse effects (i.e., life-threatening, hospitalization, persistent disability) will be 
assessed at a case-by-case basis. Anticipated adverse events and side effects for 
weight-reducing diets and/or medication intensification may include hypoglycemia, 
hypotension, gallbladder disease, headache, weakness, muscle cramps, constipation, 
diarrhea, and dehydration. Many of these effects related to dietary change are transient 
or easily treated, and can be prevented with adequate hydration, which will be 
emphasized in the dietary counseling. A study physician will be on call at all times to 
manage any adverse events felt to be related to the study. Patients with adverse events 
that are not related to the study will be referred to appropriate health care sources. All 
adverse events will be reported to the IRB according to local IRB requirements and 
reviewed by a Data Monitoring Committee (DMC) consisting of the study statistician and 
two additional members (at least one will be a physician with experience in diabetes care 
and at least one will have research experience) who are independent of the study team. 
 
13. Privacy, Data Storage & Confidentiality – see Section 12 of the e-IRB submission 
form and complete the questions in that section.   
 

Incentives Research Summary  
3/1/2018 
 
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Kenchaiah S, Evans JC, Levy D, et al. Obesity and the risk of heart failure. New 
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Wilson PW, D'Agostino RB, Sullivan L, Parise H, Kannel WB. Overweight and 
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Fontaine KR, Barofsky I. Obesity and health-related quality of life. Obesity 
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