Clinical trial NCT03698955: Low-Fat Vegan Diet Versus a Mediterranean Diet on Body Weight
Official title: A Randomized, Cross-Over Trial on the Effects of a Low-Fat Vegan Diet Versus a Mediterranean Diet on Body Weight
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Overweight
Obesity
Insulin Resistance
Keywords: Plant-based diet
Mediterranean diet
Vegan diet
Metabolism
Insulin sensitivity
Cholesterol
Advanced glycation end-products
Lead sponsor: Physicians Committee for Responsible Medicine
Sponsor class: OTHER
First posted: 2018-10-09
Enrollment: 62
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: TREATMENT

Brief summary: This randomized, cross-over trial aims to assess changes in body weight, plasma lipids, insulin sensitivity, and postprandial metabolism with a low-fat, plant-based diet and a Mediterranean diet, both followed for 4 months.

Detailed description: In a 36-week cross-over trial, overweight adults will consume a low-fat vegan diet and a Mediterranean diet in two separate 16-week phases. Changes in body weight will be the primary dependent variable. In addition, plasma lipid concentrations, insulin sensitivity, and postprandial metabolism will also be assessed and changes over time will be compared between the two diets.

Participants will be randomly assigned to start either a low-fat vegan diet or a Mediterranean diet for 16 weeks. Both groups will receive weekly classes and support, and will be asked to make no changes to their exercise patterns for the study period. After a 4-week washout period, participants will cross over to the second dietary intervention for another 16 weeks.

Eligibility criteria: Inclusion Criteria:

* Men and women age ≥18 years of age
* Body mass index 28-40 kg/m2

Exclusion Criteria:

* Diabetes mellitus type 1, history of any endocrine condition that would affect body weight, such as thyroid disease, pituitary abnormality, or Cushing's syndrome
* Smoking during the past six months
* Alcohol consumption of more than 2 drinks per day or the equivalent, episodic increased drinking (e.g., more than 2 drinks per day on weekends), or a history of alcohol abuse or dependency followed by any current use
* Use of recreational drugs in the past 6 months
* Use within the preceding six months of medications that affect appetite or body weight, such as estrogens or other hormones, thyroid medications (unstable dose within the preceding 6 months), systemic steroids, antidepressants (tricyclics, MAOIs, SSRIs), antipsychotics, lithium, anticonvulsants, appetite suppressants or other weight-loss drugs, herbs for weight loss or mood, St. John's wort, ephedra, beta blockers
* Pregnancy or intention to become pregnant during the study period, as verified by self--- - Unstable medical or psychiatric illness
* Evidence of an eating disorder
* Likely to be disruptive in group sessions
* Already following a low-fat vegan diet or Mediterranean diet
* Lack of English fluency
* Inability to maintain current medication regimen
* Inability or unwillingness to participate in all components of the study
* Intention to follow another weight-loss method during the trial

Primary outcomes:
measure: Body weight
timeFrame: Change in body weight from Baseline at 4 months
measure: Plasma lipids
timeFrame: Change in plasma cholesterol, triglycerides, and HbA1c from Baseline at 4 months
measure: Insulin sensitivity
timeFrame: Change in insulin sensitivity from Baseline at 4 months
measure: Metabolism
timeFrame: Changes in metabolism from Baseline at 4 months
Secondary outcomes:
measure: Levels of Advanced Glycosylation Endproducts (AGEs)
timeFrame: Change in Advanced Glycosylation Endproducts (AGEs) from Baseline at 4 months
measure: Endothelial function
timeFrame: Change in Endothelial function from Baseline at 4 months
measure: Microbiome analysis
timeFrame: Change in Microbiome from Baseline at 4 months
measure: Dietary Advanced Glycation End Products (AGEs)
timeFrame: 16 weeks
measure: PDI, hPDI, uPDI
timeFrame: 16 weeks
measure: Ultraprocessed foods
timeFrame: 16 weeks
measure: Carbon Footprint
timeFrame: 16 weeks
measure: Food costs
timeFrame: 16 weeks
Other outcomes:
Locations:
city: Washington
country: United States
facility: Physicians Committee for Responsible Medicine
state: District of Columbia
Study officials:
affiliation: Physicians Committee for Responsible Medicine
name: Neal Barnard
role: PRINCIPAL_INVESTIGATOR
References:
citation: Kahleova H, McCann J, Alwarith J, Rembert E, Tura A, Holubkov R, Barnard ND. A plant-based diet in overweight adults in a 16-week randomized clinical trial: The role of dietary acid load. Clin Nutr ESPEN. 2021 Aug;44:150-158. doi: 10.1016/j.clnesp.2021.05.015. Epub 2021 May 29.
citation: Barnard ND, Alwarith J, Rembert E, Brandon L, Nguyen M, Goergen A, Horne T, do Nascimento GF, Lakkadi K, Tura A, Holubkov R, Kahleova H. A Mediterranean Diet and Low-Fat Vegan Diet to Improve Body Weight and Cardiometabolic Risk Factors: A Randomized, Cross-over Trial. J Am Nutr Assoc. 2022 Feb;41(2):127-139. doi: 10.1080/07315724.2020.1869625. Epub 2021 Feb 5.