Ultra‑processed foods and muscle

A new imaging study found that people who ate more ultra‑processed foods had more fat stored inside their thigh muscles, a sign of poorer muscle quality. (rsna.org) The study, published April 14 in *Radiology*, analyzed 615 adults in the National Institutes of Health-backed Osteoarthritis Initiative who had not yet developed knee osteoarthritis on imaging. The group’s average age was 60, and participants got about 41% of their food over the prior year from ultra‑processed products. (rsna.org) Researchers said the link held even after accounting for calorie intake, fat intake, physical activity and sociodemographic factors. The muscle change they tracked was intramuscular fat on magnetic resonance imaging, or fat that accumulates inside muscle tissue rather than under the skin. (rsna.org) Ultra‑processed foods are a category in the NOVA system that sorts foods by how industrially altered they are, not just by nutrients on the label. The British Nutrition Foundation said the category is broad and that the United Kingdom still has no agreed government definition of ultra‑processed food in dietary advice. (nutrition.org.uk) That definitional problem is showing up in consumer research. A qualitative study of 30 adults in the United Kingdom found many people saw ultra‑processed foods as unhealthy but struggled to define them or separate them from other processed foods. (news-medical.net) A U.S. survey released April 15 by Purdue University found the same tension in shopping habits. Among 1,200 consumers, 35% said ultra‑processed foods are unhealthy and should be avoided, while 56% said some or many can fit into a healthy diet. (ag.purdue.edu) Purdue’s survey found convenience and time savings were the top reason people buy ultra‑processed foods, with affordability, taste and shelf life next. The report’s lead author, Joseph Balagtas, said the foods are “not clearly defined,” even as concern about their health effects averaged 7.1 out of 10. (ag.purdue.edu) The health debate did not start with this muscle study. A 2024 *BMJ* umbrella review covering nearly 9.9 million people found direct associations between greater ultra‑processed food exposure and 32 of 45 health parameters, including cardiovascular disease mortality and type 2 diabetes. (bmj.com) Not all nutrition groups read that evidence the same way. The British Nutrition Foundation said most studies linking ultra‑processed foods to poor health are observational and do not clearly prove that processing itself, rather than overall diet and lifestyle, is the cause. (nutrition.org.uk) The public mood is still shifting against the category. FoodNavigator reported April 20 that criticism now spans medical journals, policymakers and influencers, adding pressure on brands as “ultra‑processed” becomes a consumer warning label as much as a scientific term. (foodnavigator.com) For now, the clearest new finding is narrow and concrete: in adults already at risk for knee problems, diets higher in ultra‑processed foods were linked to fattier thigh muscles on scans. The argument over what counts as ultra‑processed is still moving almost as fast as the backlash itself. (rsna.org)