Vegetarian Nutrition (VN) DPG Public Library

Tran, Dale, Jensen, et al.
Journal: Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy
Published: 2020

Key Points

• Objective: The purpose of this review was to evaluate intervention studies assessing the effects of different plant-based diets on BMI and weight.

• Methods: Studies were included if they implemented an intervention, outcomes included changes in weight and/or BMI, calories were not restricted in both study groups, a vegetarian or vegan diet was part of the intervention, the study duration was at least 4 months and only included adults >18 years. Twenty-two publications from 19 studies were included, only 3 were not randomized controlled trials.

• Results: Eight of the 22 articles reported a significant reduction in body weight and/or BMI in the vegan/vegetarian group alone. Nine other articles revealed a significantly greater reduction of one of the outcomes in the vegan/vegetarian groups compared to a control group.

Conclusion

The authors concluded that changing to a plant-based diet may be beneficial toward weight and BMI in people with overweight, type 2 diabetes, cardiovascular disease, or rheumatoid arthritis. Weight loss was attributed to increased intakes of fiber, polyunsaturated fats, and plant proteins in addition to reduced energy intake, saturated fats, and animal proteins. Many of the studies in this systematic review restricted fat and/or energy intake, and therefore, the observed improvements in weight/BMI cannot be entirely attributed to the plant-based diet mechanisms. The varying macronutrient composition and energy content likely also contributed to the observed effects.

Editor's Note: In general, there is a positive effect of plant-based diets on weight however, several studies found that calorie-restricted diets are just as effective as vegan/vegetarian diets. Increased dietary fiber is known to slow gastric emptying and thereby promote satiety. A plant-based diet that is high in fiber and limited in unsaturated fat and refined grains can aid in reducing caloric intake and thereby promote weight loss.