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

Obesity Clinical Trial

Official title:

A Randomized, Cross-Over Trial on the Effects of a Low-Fat Vegan Diet Versus a Mediterranean Diet on Body Weight

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT03698955
• Other study ID #: Pro00029777
• Status: Completed
• Phase: N/A
• Start date: October 22, 2018
• Est. completion date: November 13, 2019

Study information

• Verified date: February 2024
• Source: Physicians Committee for Responsible Medicine
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 62
• Est. completion date: November 13, 2019
• Est. primary completion date: November 13, 2019
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years and older

Eligibility

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

Related Conditions & MeSH terms

• Body Weight
• Insulin Resistance
• Obesity
• Overweight

Intervention

Other:
• Plant-based diet
Weekly instructions will be given to the participants in the intervention group about following the vegan diet.
• Mediterranean Diet
Weekly instructions will be given to the participants in the intervention group about following the Mediterranean diet.

Locations

Country	Name	City	State
United States	Physicians Committee for Responsible Medicine	Washington	District of Columbia

Sponsors (1)

Lead Sponsor	Collaborator
Physicians Committee for Responsible Medicine

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	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
Primary	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
Primary	Insulin sensitivity	Insulin sensitivity will be assessed by the HOMA index.	Change in insulin sensitivity from Baseline at 4 months
Primary	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	Levels of Advanced Glycosylation Endproducts (AGEs)	An AGE reader will be used to measure the Levels of the AGEs in the skin	Change in Advanced Glycosylation Endproducts (AGEs) from Baseline at 4 months
Secondary	Endothelial function	Endothelial function will be measured using the EndoPAT.	Change in Endothelial function from Baseline at 4 months
Secondary	Microbiome analysis	Microbiome analysis will be performed from participant-provided stool sample. Anticipated changes in the dietary intervention group include changes in the microbiome composition that correlate with changes in insulin sensitivity.	Change in Microbiome from Baseline at 4 months
Secondary	Dietary Advanced Glycation End Products (AGEs)	Explore the effectiveness of a vegan diet in reducing dietary AGEs.	16 weeks
Secondary	PDI, hPDI, uPDI	Assess the total plant-based index (PDI), healthy PDI, and unhealthy PDI, and their relationship with weight loss.	16 weeks
Secondary	Ultraprocessed foods	The consumption of ultraprocessed foods will be assessed, using the NOVA classification, at baseline and 16 weeks.	16 weeks
Secondary	Carbon Footprint	The greenhouse gas emissions (GHGE) and cumulative energy demand (CED) will be assessed, using the database of Food Impacts on the Environment for Linking to Diets (dataFIELD) and What We Eat In America (WWEIA) database, at baseline and 16 weeks.	16 weeks