Cited by 452Nutritional Studies and DietDiet and metabolism studiesDiabetes, Cardiovascular Risks, and Lipoproteins

A low-fat vegan diet and a conventional diabetes diet in the treatment of type 2 diabetes: A randomized, controlled, 74-wk clinical trial

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Barnard, Neal D, Cohen, Joshua, Jenkins, David JA, Turner-McGrievy, Gabrielle, Gloede, Lise, Green, Amber, Ferdowsian, Hope·2009·The American Journal of Clinical Nutrition

Abstract

Background Low-fat vegetarian and vegan diets are associated with weight loss, increased insulin sensitivity, and improved cardiovascular health.Objective We compared the effects of a low-fat vegan diet and conventional diabetes diet recommendations on glycemia, weight, and plasma lipids.Design Free-living individuals with type 2 diabetes were randomly assigned to a low-fat vegan diet (n = 49) or a diet following 2003 American Diabetes Association guidelines (conventional, n = 50) for 74 wk. Glycated hemoglobin (Hb A(1c)) and plasma lipids were assessed at weeks 0, 11, 22, 35, 48, 61, and 74. Weight was measured at weeks 0, 22, and 74.Results Weight loss was significant within each diet group but not significantly different between groups (-4.4 kg in the vegan group and -3.0 kg in the conventional diet group, P = 0.25) and related significantly to Hb A(1c) changes (r = 0.50, P = 0.001). Hb A(1c) changes from baseline to 74 wk or last available values were -0.34 and -0.14 for vegan and conventional diets, respectively (P = 0.43). Hb A(1c) changes from baseline to last available value or last value before any medication adjustment were -0.40 and 0.01 for vegan and conventional diets, respectively (P = 0.03). In analyses before alterations in lipid-lowering medications, total cholesterol decreased by 20.4 and 6.8 mg/dL in the vegan and conventional diet groups, respectively (P = 0.01); LDL cholesterol decreased by 13.5 and 3.4 mg/dL in the vegan and conventional groups, respectively (P = 0.03).Conclusions Both diets were associated with sustained reductions in weight and plasma lipid concentrations. In an analysis controlling for medication changes, a low-fat vegan diet appeared to improve glycemia and plasma lipids more than did conventional diabetes diet recommendations. Whether the observed differences provide clinical benefit for the macro- or microvascular complications of diabetes remains to be established. This trial was registered at clinicaltrials.gov as NCT00276939.

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  • People following low-carbohydrate diets may need long-term reductions in diabetes medication doses.

    “Even so, persons on low-carbohydrate diets may chronically experience the need for reductions in doses of DM medications.711,712”

    From American Association of Clinical Endocrinology Clinical Practice Guideline: Developing a Diabetes Mellitus Comprehensive Care Plan-2022 Update. (2022) · cites this paper as [712]

    The Intervention section describes a low-fat vegan diet and a conventional diabetes diet, not low-carbohydrate diets. The Dietary intake, adherence, and medication changes section reports that some participants had lower diabetes-medication dosages after 74 weeks, but it does not establish that people following low-carbohydrate diets may need such reductions. (LLM, conf=0.87)

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  • Vegetarian or vegan eating plans often resulted in weight loss.

    “These eating plans often resulted in weight loss (92 -97).”
  • Vegetarian or vegan eating plans often resulted in weight loss.

    “These eating plans often resulted in weight loss (92 -97).”
  • Low-carbohydrate diets reducing carbohydrates to 26% to 46% of daily calories and very low-carbohydrate diets restricting carbohydrates to 20 to 50 grams per day sufficient to induce ketosis are both safe for people with type 2 diabetes.

    “Low-carbohydrate diets that reduce carbohydrates to 26% to 46% of daily calories and very lowecarbohydrate diets that restrict carbohydrates to 20 to 50 grams per day sufficient to induce ketosis are both safe for persons with T2D.707–714,929,930”

    From American Association of Clinical Endocrinology Clinical Practice Guideline: Developing a Diabetes Mellitus Comprehensive Care Plan-2022 Update. (2022) · cites this paper as [712]

    The Intervention section describes a low-fat vegan diet prescribed at 75% carbohydrate and a conventional diabetes diet, not either low-carbohydrate regimen in the claim. A search for the stated carbohydrate ranges, ketosis, and low-carbohydrate safety found no passage assessing whether those regimens are safe for people with type 2 diabetes. (LLM, conf=0.76)

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  • Three other trials found no differences between lacto-vegetarian or vegan diets versus conventional dietary recommendations for improving weight loss, blood pressure, blood lipids, or insulin resistance.

    “Three other trials found no differences between lacto-vegetarian or vegan diets versus conventional dietary recommendations for improving weight loss, BP, blood lipids, or insulin resistance.119–122”

    From Components of a Cardioprotective Diet: New Insights (2011) · cites this paper as [120]

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Authors
Barnard, N. D., Cohen, J., Jenkins, D. J., Turner-McGrievy, G., Gloede, L., Green, A., & Ferdowsian, H.
Affiliations
University of North Carolina at Chapel Hill (US)
Corresponding author
Barnard, Neal D
Venue
The American Journal of Clinical Nutrition
Publisher
Elsevier BV
Published
2009-05
Volume
89
Issue
5
Pages
1588S-1596S
ISSN
0002-9165 (ISSN-L)
OpenAlex
W2114345764
Cited by
449
References
66
Citations by year
2026: 16 · 2025: 25 · 2024: 33 · 2023: 35 · 2022: 30 · 2021: 28 · 2020: 35 · 2019: 43 · 2018: 21 · 2017: 22 · 2016: 22 · 2015: 23 · 2014: 29 · 2013: 19 · 2012: 14
FWCI
22.08
Type
journal article
Language
en
Open access
Locations
  • American Journal of Clinical Nutrition (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • Diabetes Action Research and Education Foundation
  • George Washington University
  • Physicians Committee for Responsible Medicine
  • National Institutes of Health (5r01dk059362-02)
  • National Institute of Diabetes and Digestive and Kidney Diseases (R01 DK059362-01A2, R01 DK059362)
Topics
  • Health Sciences › Medicine › Public Health, Environmental and Occupational Health › Nutritional Studies and Diet
  • Health Sciences › Medicine › Physiology › Diet and metabolism studies
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Diabetes, Cardiovascular Risks, and Lipoproteins
Keywords
vegetarian diet, HbA1c, glycemic control, weight loss, plasma lipids, LDL cholesterol, total cholesterol, lipid-lowering drugs
MeSH terms
Blood Glucose, Body Weight, Cholesterol, Diabetes Mellitus, Type 2, Dietary Fats, Glycated Hemoglobin, Humans, Lipoproteins, HDL, Lipoproteins, LDL, Time Factors, Diet, Vegetarian, Vitamin B 12, Weight Loss, Diet Records, Diet, Fat-Restricted, Dietary Supplements

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