Low-Fat Vegan Diet Promotes Weight Loss by Lowering Dietary Energy Density

The secondary analysis of a randomized clinical trial found that a low-fat vegan diet reduced dietary energy density by approximately 30%, leading to lower energy intake and greater weight loss without prescribed calorie restriction. The study included 244 adults with overweight who were randomly assigned to either an ad libitum low-fat vegan diet or no dietary changes for 16 weeks, with 223 participants completing the trial. Total food weight consumed remained unchanged, but daily energy intake fell significantly more in the vegan group than in controls (−357 kcal/day between groups). The reduction in dietary energy density was driven by eliminating animal foods and increasing low-energy-density plant foods, particularly vegetables and legumes, while intake of fruits and nondairy alternatives also increased. Lower dietary energy density was significantly associated with greater weight loss, and this relationship remained significant even after adjusting for changes in energy intake, suggesting that dietary energy density independently contributes to weight loss. The findings indicate that emphasizing high-fiber, water-rich plant foods can reduce calorie intake while maintaining food volume and satiety, providing a practical physiological mechanism for the weight loss and metabolic benefits of a low-fat vegan diet without intentional calorie restriction. Source: https://jamanetwork.com/