Low-Fat Vegan Diet Versus a Mediterranean Diet on Body Weight

NCT03698955 | Completed DMC

• 1 other identifier: Pro00029777
• Study Type: interventional
• Target: 62
• Locations: 1 country
• Sites: 1

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.

Conditions

Overweight; Obesity; Insulin Resistance

Keywords

Plant-based diet; Mediterranean diet; Vegan diet; Metabolism; Insulin sensitivity; Cholesterol; Advanced glycation end-products

Outcome Measures

Primary Outcomes (4)

• Body weight

  Body weight will be assessed at the baseline and at the completion of both interventions.

  Change in body weight from Baseline at 4 months

• Plasma lipids

  Plasma cholesterol, triglycerides, and HbA1c will be measured in a fasting state.

  Change in plasma cholesterol, triglycerides, and HbA1c from Baseline at 4 months

• Insulin sensitivity

  Insulin sensitivity will be assessed by the HOMA index.

  Change in insulin sensitivity from Baseline at 4 months

• Metabolism

  Participants will be asked to report to the laboratory within 60 minutes of waking and after a 12-hour fast. Following 30 minutes of quiet rest in a dimly lit room, pulse, respiratory rate, and body temperature will be measured. REE will be measured for 20 minutes through indirect calorimetry (Cosmed Quark RMR, Chicago, IL) utilizing a ventilated hood system. The laboratory temperature will be maintained at 23 degrees C throughout, and precautions will be taken to minimize any disturbances that could affect the metabolic rate. For premenopausal women, measures will be timed so as to occur in the luteal phase of the menstrual cycle. Postprandial metabolism will be measured for three hours after the standard meal.

  Changes in metabolism from Baseline at 4 months

Secondary Outcomes (8)

• Levels of Advanced Glycosylation Endproducts (AGEs)

  Change in Advanced Glycosylation Endproducts (AGEs) from Baseline at 4 months

• Endothelial function

  Change in Endothelial function from Baseline at 4 months

• Microbiome analysis

  Change in Microbiome from Baseline at 4 months

• Dietary Advanced Glycation End Products (AGEs)

  16 weeks

• PDI, hPDI, uPDI

  16 weeks

Study Arms (2)

Plant-based diet

ACTIVE COMPARATOR

The diet group will be asked to follow a low-fat, vegan diet for 16 weeks.

Other: Plant-based diet

Mediterranean diet

ACTIVE COMPARATOR

The diet group will be asked to follow a Mediterranean diet for 16 weeks.

Other: Mediterranean Diet

Interventions

Plant-based diet OTHER

Weekly instructions will be given to the participants in the intervention group about following the vegan diet.

Also known as: Vegan diet

Plant-based diet

Mediterranean Diet OTHER

Weekly instructions will be given to the participants in the intervention group about following the Mediterranean diet.

Mediterranean diet

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

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

You may not qualify if:

• 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

Sponsors & Collaborators

• Physicians Committee for Responsible Medicine: lead

Study Sites (1)

Physicians Committee for Responsible Medicine

Washington D.C., District of Columbia, 20016, United States

Location

Related Publications (5)

• Kahleova H, Smith R, Fischer I, Brennan H, Znayenko-Miller T, Holubkov R, Barnard ND. Plant-based dietary index on the Mediterranean and a vegan diet: a secondary analysis of a randomized, cross-over trial. Front Nutr. 2025 Nov 19;12:1666807. doi: 10.3389/fnut.2025.1666807. eCollection 2025.

  PMID: 41346691 DERIVED

• Kahleova H, Maracine C, Himmelfarb J, Jayaraman A, Znayenko-Miller T, Holubkov R, Barnard ND. Dietary acid load on the Mediterranean and a vegan diet: a secondary analysis of a randomized, cross-over trial. Front Nutr. 2025 Jun 25;12:1634215. doi: 10.3389/fnut.2025.1634215. eCollection 2025.

  PMID: 40635898 DERIVED

• Kahleova H, Znayenko-Miller T, Motoa G, Eng E, Prevost A, Uribarri J, Holubkov R, Barnard ND. Dietary advanced glycation end-products and their associations with body weight on a Mediterranean diet and low-fat vegan diet: a randomized, cross-over trial. Front Nutr. 2024 Aug 8;11:1426642. doi: 10.3389/fnut.2024.1426642. eCollection 2024.

  PMID: 39176029 DERIVED

• 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.

  PMID: 34330460 DERIVED

• 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.

  PMID: 33544066 DERIVED

MeSH Terms

Conditions

Overweight; Obesity; Insulin Resistance

Interventions

Diet, Plant-Based; Diet, Vegan; Diet, Mediterranean

Condition Hierarchy (Ancestors)

Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Hyperinsulinism; Glucose Metabolism Disorders; Metabolic Diseases

Intervention Hierarchy (Ancestors)

Diet Therapy; Nutrition Therapy; Therapeutics; Diet; Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena; Diet, Vegetarian

Study Officials

• Neal Barnard

  Physicians Committee for Responsible Medicine

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: October 3, 2018
• First Posted: October 9, 2018
• Study Start: October 22, 2018
• Primary Completion: November 13, 2019
• Study Completion: November 13, 2019
• Last Updated: September 27, 2024

Record last verified: 2024-02

Locations

US (1)