The research findings were published in the International Journal of Applied and Basic Nutritional Sciences, and compared the amount of weight lost by those on vegan diets to those on a mostly plant-based diet, and those eating an omnivorous diet with a mix of animal products and plant based foods.
A six month period was used as the time frame to measure weight loss and it was determined that individuals on the vegan diet lost more weight than the other two groups by an average of 4.3%, or 16.5 pounds.
Research participants were randomly assigned to one of five diets including: vegan which excludes all animal products, semi-vegetarian with occasional meat intake; pesco-vegetarian which excludes all meat except seafood; vegetarian which excludes all meat and seafood but includes animal products, and omnivorous, which excludes no foods.
Weight loss was not the only positive health benefit for participants in the strictly vegan group. They also showed the greatest amount of decrease in their fat and saturated fat levels at the two and six month checks, had lower BMIs, and improved macro nutrients more than other diets. Eschewing all animal products appears to be key for these positive results. “I personally was surprised that the pesco-vegetarian group didn’t fare better with weight loss. In the end, their loss was no different than the semi-vegetarian or omnivorous groups,” said Turner McGrievy said an assistant professor at the University of South Carolina in the Department of Health Promotion, Education, and Behavior.
Gabrielle M. Turner-McGrievy, Charis R. Davidson, Ellen E. Wingard, Sara Wilcox, Edward A. Frongillo. Comparative effectiveness of plant-based diets for weight loss: A randomized controlled trial of five different diets. Nutrition, 2014; DOI: 10.1016/j.nut.2014.09.002