Vegan Diet Increases Weight Loss and Insulin Sensitivity
|Grilled Polenta with Portabella Mushrooms|
A low-fat, plant-based diet is more effective at helping women lose weight and improve insulin sensitivity than a low-fat omnivorous diet, shows a new study appearing in the September issue of The American Journal of Medicine. The study, involving 59 overweight, postmenopausal women, was conducted by PCRM president Neal Barnard, M.D., with colleagues from Georgetown University Hospital and George Washington University. Half the study participants followed a vegan diet; the other half followed a control diet based on National Cholesterol Education Program guidelines.
Those in the vegan group lost about one pound a week—about the same amount most low-calorie dieters can expect—and twice as much as the control group. But the vegan group didn’t have to limit calories, portions, or carbohydrates.
Although most of the weight loss is apparently due to the naturally low calorie content of a plant-based diet, the study also showed that vegan dieters increased their after-meal calorie burn. Investigators measured each participant’s calorie-burning speed by measuring how much oxygen she consumed minute by minute, and how much carbon dioxide she exhaled while at rest. Then, each woman drank a liquid meal, and her calorie-burning speed was measured over the next three hours. After 14 weeks on the vegan diet, the women had a noticeable jump in their after-meal burn, while those in the control group had no significant change.
Researchers also noted that the vegan diet improved the dieters’ insulin sensitivity, meaning their cells were able to pull glucose out of their bloodstream more quickly. This result suggests that a vegan diet may help in managing diabetes, the subject of PCRM’s newest study, whose initial results were presented this summer at the American Diabetes Association’s 65th Scientific Sessions in San Diego and the American Association of Diabetes Educators in Washington, D.C.