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Low-Fat, Plant-Based Diet Reduces T2D Risk in Obese Individuals

by Bianca Garilli, ND

It is estimated that over 9% of the US population or 30.3 million people have diabetes, and 23% of these are undiagnosed.1 The pathogenesis of diabetes includes the development of insulin resistance in muscle and liver cells, followed by impairment of pancreatic beta-cell function. Eventually, there is beta-cell failure due to apoptosis which leads to loss of first-phase insulin secretion.

Research, however, indicates diet and physical exercise may reduce the deterioration of beta-cell health.  Individuals following a plant-based diet have been shown to have a 46-74% lower prevalence of diabetes than the non-vegetarian population but, until recently, the mechanisms underlying this association were unclear.

To learn more about the effects of a plant-based dietary intervention on beta-cell function prior to a diabetes diagnosis, a single-center, randomized, open parallel study consisting of 75 obese men and women was conducted.2 Participants were between the ages of 25-75 years old with a BMI ranging from 28 to 40. Individuals were randomized to the intervention or control group and were examined at baseline and again at the end of the 16-week study. The intervention group followed a low-fat vegan diet, with approximately 75% of their total daily energy coming from carbohydrates, while protein made up 15% and fat the remaining 10%. It was recommended that the intervention group consume vegetables, grains, legumes and fruits while avoiding animal products. The participants were asked to avoid added fats while maintaining a daily fat intake of 20-30 grams through food sources; they were supplemented with 500 mcg/day of vitamin B12. In both the intervention and control group, alcohol was limited to one serving per day for women and two per day for men.2

At the end of the 16-week trial, participants following a low-fat, plant-based diet experienced:2

  • Increase in meal-stimulated insulin secretion and beta-cell glucose sensitivity
  • Reduction in fasting insulin resistance
  • Reduction infasting and postprandial plasma glucose concentrations

The favorable changes noted in this study are supportive for reducing the risk of progression to type 2 diabetes, a common outcome seen in individuals with similar biomarkers as the study participants’ baseline testing results. It has been found that a plant-based diet not only supports improved insulin sensitivity and beta-cell function, but also promotes a healthy body weight, increases fiber and phytonutrient content, supports a healthy gut microbiota population, and reduces levels of saturated fat, advanced glycation end products, nitrosamines, and heme iron – all mechanims which improve insulin and glucose control.3

Why is this Clinically Relevant?

  • Low-fat, plant-based dietary patterns should be considered as part of a therapeutic lifestyle intervention in individuals with family history and personal risk factors for developing T2D
  • Screening for insulin, glucose and beta-cell dysfunction should be a regular part of annual screenings
  • Low-fat, plants-based diets may be utilized to promote healthy BMI, high fiber and phytonutrient intake and reduction of foods leading to inflammation and oxidative stress
  • Addition of regular physical exercise also supports improved glucose and insulin control
  • It is important to recommend healthy, complex, unprocessed carbohydrates when encouraging a vegetarian diet

Link to Article


1. CDC. National Diabetes Statistics Report, 2017. Accessed April 13, 2018.

2. Kahleova H, Tura OA, Hill M, Holubkov R, Barnard ND. A plant-based dietary intervention improves beta-cell function and insulin resistance in overweight adults: a 16-week randomized clinical trial. Nutrients. 2018;10(2):E189.

3. McMacken M, Shah S. A plant-based diet for the prevention and treatment of type 2 diabetes.  J Geriatr Cardiol. 2017;14(5):342–354.


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