Vegan vs. Mediterranean Diets: Unpacking Short-Term Weight and Metabolic Benefits

A low-fat vegan eating pattern produced greater short-term weight loss than a Mediterranean pattern in adults with excess weight in a 16-week randomized trial—signaling measurable metabolic gains within weeks.

The 16‑week trial enrolled 62 adults to compare weight loss and cardiometabolic outcomes between the two patterns.

The low‑fat vegan diet yielded an additional mean weight loss of about 2.6 kg versus the Mediterranean diet over the active intervention. That magnitude of difference occurred during the 16-week feeding interval and represents a clinically relevant short-term effect.

The larger weight loss reflected pattern-level changes: broad elimination of animal foods, reduced oils and nuts, and lower dietary energy density leading to decreased caloric intake. These combined behavioral and compositional shifts accounted for most of the between-group difference and provide a practical framework for counseling—emphasize plant-food substitution while limiting added fats when weight loss is the goal.

Intake of refined grains, potatoes, and other plant foods commonly labeled "unhealthy" increased in the vegan arm but nonetheless correlated with weight loss within the low-fat framework. In this context those foods displaced animal products and added fats, lowering meal energy density and total calories—demonstrating that a food's label alone did not preclude short-term weight loss when the overall pattern reduced energy intake.

In sum, removing animal products and limiting added oils can accelerate short-term weight and metabolic improvements among adults with excess weight.