A low-fat vegan diet may do more than cut calories — it can shift your body chemistry in ways that support metabolic health. That’s the finding from a new randomized trial showing that a vegan diet significantly lowers dietary acid load, a measure linked to chronic inflammation, weight gain and type 2 diabetes risk.
Published in Frontiers in Nutrition, the study compared two popular eating styles: a Mediterranean diet and a low-fat vegan diet. Over 16 weeks, 62 overweight adults followed each plan in a randomized, crossover design. Only the vegan diet led to a significant drop in dietary acid load, measured by two accepted scoring methods: PRAL (Potential Renal Acid Load) and NEAP (Net Endogenous Acid Production).
“Eating acid-producing foods like meat, eggs, and dairy can increase the dietary acid load,” said lead author Hana Kahleova, MD, PhD, of the Physicians Committee for Responsible Medicine. “But replacing animal products with plant-based foods like leafy greens, berries, and legumes can help promote weight loss and create a healthy gut microbiome.”
The study found that participants lost an average of 13.2 pounds on the vegan diet, while there was no significant weight change on the Mediterranean plan. Importantly, the drop in acid load remained strongly linked to weight loss — even after accounting for calorie intake.
While both diets included fruits and vegetables, only the vegan diet fully eliminated acid-producing animal products. The researchers note that the alkalizing effect of plant-based foods — including leafy greens, legumes, fruits and certain grains — may play a key role in supporting metabolic balance.
The results suggest that diet quality, not just quantity, can influence weight and diabetes risk — especially through pathways like inflammation and acid-base balance. The study received no external funding.