Ultra-Processed Foods Double Fat Gain Without Extra Calories.

In 2025, Jessica M. Preston and Romain Barrès from the University of Copenhagen studied 43 men aged 20-35 in a crossover trial. Participants spent three weeks on ultra-processed diets (like processed meats and snacks) and three on unprocessed diets (whole foods), with equal calories, followed by a washout period. They measured weight, hormones, and pollutants in blood.

Ultra-processed diets caused 2.2 lbs more fat gain than unprocessed, even at same calories, and raised phthalate cxMINP levels, a hormone disruptor. Testosterone and follicle-stimulating hormone dropped, linked to poor sperm quality, while unprocessed diets kept hormones stable.

Swap ultra-processed foods for whole ones to avoid fat gain and hormone issues.