Less Processed Diet May Be More Beneficial for Weight Loss

TUESDAY, Aug. 5, 2025 (HealthDay News) — Diets high in ultra-processed food (UPF), even those meeting national dietary guidelines, may be less effective for weight loss than minimally processed food (MPF) diets, according to a study published online Aug. 4 in Nature Medicine.

Samuel J. Dicken, Ph.D., from University College London, and colleagues conducted a 2 × 2 crossover randomized controlled feeding trial, in which 55 adults (body mass index ≥25 to <40 kg/m² and habitual UPF intake ≥50 percent kcal/day) were provided with two eight-week ad libitum, pre-prepared diets following the UK Eatwell Guide: an MPF diet and UPF diet (in a random order).

The researchers found that both diets resulted in weight loss (percent weight change, −2.06 and −1.05 for MPF and UPF, respectively). The percent weight change with the MPF diet was significantly greater (change in percent weight change, −1.01; Cohen”s d, −0.48). Both diets were commonly tied to mild gastrointestinal adverse events.

“If we scaled these results up over the course of a year, we’d expect to see a 13 percent weight reduction in men and a 9 percent reduction in women on the minimally processed diet, but only a 4 percent weight reduction in men and 5 percent in women after the ultra-processed diet,” Dicken said in a statement. “Over time this would start to become a big difference.”

Several authors disclosed ties to relevant organizations.

Abstract/Full Text