25592014
OBJECTIVE	The aim of this study was to determine the effect of plant-based diets on weight loss .
METHODS	Participants were enrolled in a 6-mo , five-arm , randomized controlled trial in 2013 in South Carolina .
METHODS	Participants attended weekly group meetings , with the exception of the omnivorous group , which served as the control and attended monthly meetings augmented with weekly e-mail lessons .
METHODS	All groups attended monthly meetings for the last 4 mo of the study .
METHODS	Diets did not emphasize caloric restriction .
RESULTS	Overweight adults ( body mass index 25-49 .9 kg/m ( 2 ) ; age 18-65 y , 19 % non-white , and 27 % men ) were randomized to a low-fat , low-glycemic index diet : vegan ( n = 12 ) , vegetarian ( n = 13 ) , pesco-vegetarian ( n = 13 ) , semi-vegetarian ( n = 13 ) , or omnivorous ( n = 12 ) .
RESULTS	Fifty ( 79 % ) participants completed the study .
RESULTS	In intention-to-treat analysis , the linear trend for weight loss across the five groups was significant at both 2 ( P < 0.01 ) and 6 mo ( P < 0.01 ) .
RESULTS	At 6 mo , the weight loss in the vegan group ( -7.5 % 4.5 % ) was significantly different from the omnivorous ( -3.1 % 3.6 % ; P = 0.03 ) , semi-vegetarian ( -3.2 % 3.8 % ; P = 0.03 ) , and pesco-vegetarian ( -3.2 % 3.4 % ; P = 0.03 ) groups .
RESULTS	Vegan participants decreased their fat and saturated fat more than the pesco-vegetarian , semi-vegetarian , and omnivorous groups at both 2 and 6 mo ( P < 0.05 ) .
CONCLUSIONS	Vegan diets may result in greater weight loss than more modest recommendations .

