The Effect of a Low-fat Vegan Dietary Intervention on Intracellular Lipid, Insulin Sensitivity, and Glycemic Control in Type 2 Diabetes

NCT06106035 | Completed DMC

• 1 other identifier: Pro00074571
• Study Type: interventional
• Target: 26
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this 16-week clinical trial is to assess the health benefits of a low-fat vegan diet on insulin sensitivity and glycemic control in type 2 diabetes. Participants will receive at no cost, study-related weekly nutrition education classes and one-on-one consultation with a registered dietitian.

Conditions

Diabetes Mellitus, Type 2; Diabetes Mellitus Type 2 in Obese

Keywords

Diabetes; Type 2; HbA1c

Outcome Measures

Primary Outcomes (9)

• Intramyocellular and Hepatocellular Lipid Content

  MR spectroscopy will be used to quantify liver and muscle fat content. This study will assess the association of attending a series of plant-based nutrition classes with pre-post changes in intramyocellular and hepatocellular lipid content.

  16-weeks

• Insulin sensitivity and β-cell function

  These will be assessed during a standard meal test (Boost Plus, Nestle, Vevey, Switzerland; 720 kcal, 34% of energy from fat, 16% protein, 50% carbohydrate). Plasma concentrations of glucose, immunoreactive insulin, and C-peptide will be measured at 0, 30, 60, 120, and 180 min. Insulin secretory rates will be calculated from plasma C-peptide levels by deconvolution49 and expressed per square meter of estimated body surface area. This study will assess the association of attending a series of plant-based nutrition classes with pre-post changes in insulin sensitivity and β-cell function.

  16-weeks

• Resting energy expenditure and postprandial metabolism

  This will be measured by indirect calorimetry. Participants will be asked to report to the laboratory within 60 minutes of waking and after a 12-hour fast. Resting energy expenditure will be measured for 20 minutes through indirect calorimetry, utilizing a ventilated hood system. Postprandial metabolism will be measured for 20 minutes in the last hour of the meal test, i.e. 2 hours after the standard breakfast. This study will assess the association of attending a series of plant-based nutrition classes with pre-post changes in resting energy expenditure and postprandial metabolism.

  16-weeks

• Body Composition

  This will be measured by dual-energy x-ray absorptiometry (Lunar iDXA). The iDXA can measure body composition with low X-ray exposure and short scanning time. This study will assess the association of attending a series of plant-based nutrition classes with pre-post changes in body composition.

  16-weeks

• Advanced Glycation End-products (AGE)

  This will be measured using the Advanced Glycation End-products (AGE) Reader made by Diagnoptics. AGE Reader measures the skin fluorescence to quantify the tissue accumulation of AGE's. This study will assess the association of attending a series of plant-based nutrition classes with pre-post changes in advanced glycation end-products (AGE).

  16-weeks

• Continuous glucose monitoring

  To provide glucose readings throughout the day, participants will be provided with a continuous glucose monitoring (CGM) system that measures glucose concentrations between 40 and 400 mg/dL every 5 minutes for up to 7 days by sampling interstitial fluid. The participants who are at risk of hypoglycemia will be encouraged to use CGM throughout the whole study.

  16-weeks

• Body Weight

  This study will assess the association of attending a series of plant-based nutrition classes with pre-post changes in body weight.

  16-weeks

• Plasma Lipid Concentrations

  This study will assess the association of attending a series of plant-based nutrition classes with pre-post changes in plasma lipid concentrations.

  16-weeks

• HbA1c

  This study will assess the association of attending a series of plant-based nutrition classes with pre-post changes in glycemic control in individuals with type 2 diabetes as assessed by hemoglobin A1c (HbA1c) and use of medication.

  16-weeks

Secondary Outcomes (3)

• Diet Quality

  16-weeks

• Food Acceptability

  16-weeks

• Food Cost

  16-weeks

Study Arms (1)

Intervention Group: low-fat vegan diet

EXPERIMENTAL

This arm of participants will be asked to attend weekly online classes in nutrition and health and to follow a low-fat, vegan diet for 16 weeks.

Behavioral: low-fat vegan diet

Interventions

low-fat vegan diet BEHAVIORAL

The intervention diet consists of whole grains, vegetables, legumes, and fruits, with no restriction on energy intake. Participants will also be guided to favor foods with a low glycemic index. Animal products and added oils will be excluded. The diet is designed to derive approximately 10% of energy from fat, approximately 10-15% of energy from protein, and the remainder from mostly complex carbohydrates. The diet will also provide approximately 40 g of fiber per day.

Also known as: low-fat, plant-based diet

Intervention Group: low-fat vegan 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 with type 2 diabetes treated by diet and/or oral hypoglycemic agents other than sulfonylureas
• Age ≥18 years
• Body mass index 26-40 kg/m2
• Medications (antidiabetic, antihypertensive, and lipid-lowering) have been stable for the past 3 months
• HbA1c between 6.0-10.5% (42-91 mmol/mol)

You may not qualify if:

• Diabetes mellitus, type 1 and/or treatment with insulin or sulfonylureas
• Metal implants, such as a cardiac pacemaker or an aneurysm clip
• 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, systemic steroids, antidepressants (tricyclics, monoamine oxidase inhibitors, selective serotonin reuptake inhibitors), 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
• Unstable medical or psychiatric illness
• Evidence of an eating disorder
• Likely to be disruptive in group sessions
• Already following a low-fat, vegan diet
• Lack of English fluency
• Inability to maintain current medication regimen
• Inability or unwillingness to participate in all components of the study

Sponsors & Collaborators

• Physicians Committee for Responsible Medicine: lead
• Yale University: collaborator

Study Sites (1)

Physicians Committee for Responsible Medicine

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

Location

Related Publications (10)

• Kahleova H, Sutton M, Maracine C, Nichols D, Monsivais P, Holubkov R, Barnard ND. Vegan Diet and Food Costs Among Adults With Overweight: A Secondary Analysis of a Randomized Clinical Trial. JAMA Netw Open. 2023 Sep 5;6(9):e2332106. doi: 10.1001/jamanetworkopen.2023.32106.

  PMID: 37669055 BACKGROUND

• Kahleova H, Petersen KF, Shulman GI, Alwarith J, Rembert E, Tura A, Hill M, Holubkov R, Barnard ND. Effect of a Low-Fat Vegan Diet on Body Weight, Insulin Sensitivity, Postprandial Metabolism, and Intramyocellular and Hepatocellular Lipid Levels in Overweight Adults: A Randomized Clinical Trial. JAMA Netw Open. 2020 Nov 2;3(11):e2025454. doi: 10.1001/jamanetworkopen.2020.25454.

  PMID: 33252690 BACKGROUND

• Yatsuya H, Nihashi T, Li Y, Hotta Y, Matsushita K, Muramatsu T, Otsuka R, Matsunaga M, Yamashita K, Wang C, Uemura M, Harada A, Fukatsu H, Toyoshima H, Aoyama A, Tamakoshi K. Independent association of liver fat accumulation with insulin resistance. Obes Res Clin Pract. 2014 Jul-Aug;8(4):e350-5. doi: 10.1016/j.orcp.2013.08.002. Epub 2013 Sep 5.

  PMID: 25091356 BACKGROUND

• Barnard ND, Cohen J, Jenkins DJ, Turner-McGrievy G, Gloede L, Jaster B, Seidl K, Green AA, Talpers S. A low-fat vegan diet improves glycemic control and cardiovascular risk factors in a randomized clinical trial in individuals with type 2 diabetes. Diabetes Care. 2006 Aug;29(8):1777-83. doi: 10.2337/dc06-0606.

  PMID: 16873779 BACKGROUND

• Itani SI, Ruderman NB, Schmieder F, Boden G. Lipid-induced insulin resistance in human muscle is associated with changes in diacylglycerol, protein kinase C, and IkappaB-alpha. Diabetes. 2002 Jul;51(7):2005-11. doi: 10.2337/diabetes.51.7.2005.

  PMID: 12086926 BACKGROUND

• Bachmann OP, Dahl DB, Brechtel K, Machann J, Haap M, Maier T, Loviscach M, Stumvoll M, Claussen CD, Schick F, Haring HU, Jacob S. Effects of intravenous and dietary lipid challenge on intramyocellular lipid content and the relation with insulin sensitivity in humans. Diabetes. 2001 Nov;50(11):2579-84. doi: 10.2337/diabetes.50.11.2579.

  PMID: 11679437 BACKGROUND

• Goodpaster BH, Theriault R, Watkins SC, Kelley DE. Intramuscular lipid content is increased in obesity and decreased by weight loss. Metabolism. 2000 Apr;49(4):467-72. doi: 10.1016/s0026-0495(00)80010-4.

  PMID: 10778870 BACKGROUND

• Krssak M, Falk Petersen K, Dresner A, DiPietro L, Vogel SM, Rothman DL, Roden M, Shulman GI. Intramyocellular lipid concentrations are correlated with insulin sensitivity in humans: a 1H NMR spectroscopy study. Diabetologia. 1999 Jan;42(1):113-6. doi: 10.1007/s001250051123.

  PMID: 10027589 BACKGROUND

• Perseghin G, Scifo P, De Cobelli F, Pagliato E, Battezzati A, Arcelloni C, Vanzulli A, Testolin G, Pozza G, Del Maschio A, Luzi L. Intramyocellular triglyceride content is a determinant of in vivo insulin resistance in humans: a 1H-13C nuclear magnetic resonance spectroscopy assessment in offspring of type 2 diabetic parents. Diabetes. 1999 Aug;48(8):1600-6. doi: 10.2337/diabetes.48.8.1600.

  PMID: 10426379 BACKGROUND

• Goodpaster BH, Thaete FL, Kelley DE. Thigh adipose tissue distribution is associated with insulin resistance in obesity and in type 2 diabetes mellitus. Am J Clin Nutr. 2000 Apr;71(4):885-92. doi: 10.1093/ajcn/71.4.885.

  PMID: 10731493 BACKGROUND

MeSH Terms

Conditions

Diabetes Mellitus, Type 2; Diabetes Mellitus

Interventions

Diet, Fat-Restricted; Diet, Plant-Based

Condition Hierarchy (Ancestors)

Glucose Metabolism Disorders; Metabolic Diseases; Nutritional and Metabolic Diseases; Endocrine System Diseases

Intervention Hierarchy (Ancestors)

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

Study Officials

• Hana Kahleova, MD, PhD

  Physicians Committee for Responsible Medicine

  PRINCIPAL INVESTIGATOR

Study Design

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

Model Details: All individuals will be on a low-fat vegan diet for the duration of the study.

Study Record Dates

• First Submitted: October 24, 2023
• First Posted: October 30, 2023
• Study Start: February 13, 2024
• Primary Completion: November 28, 2025
• Study Completion: November 28, 2025
• Last Updated: January 20, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)