Low-Fat Vegan Diet Reduces Energy Density

A secondary analysis of a 16-week randomized clinical trial, published in JAMA Network Open, found that adults with overweight who followed an ad libitum low-fat vegan diet reduced the energy density of their food by about 30%, allowing them to eat the same weight of food while consuming roughly 357 fewer calories per day and losing more weight, without intentional calorie restriction. The study, led by Hana Kahleova of the Physicians Committee for Responsible Medicine, measured energy density as calories per gram and found that the reduction was driven by replacing calorie-dense animal foods with high-volume, low-energy-density plant foods such as vegetables and legumes. The analysis showed that greater reductions in energy density were associated with greater weight loss, even after accounting for changes in calorie intake. The findings suggest that targeting dietary composition rather than portion size may offer a practical weight-loss strategy, though the study is a secondary analysis and does not compare the vegan diet to other dietary approaches.