Small change in diet may improve cholesterol in older adults

An 18-week randomized, controlled feeding trial of 36 adults aged 65+ found that sharply reducing ultra-processed food intake and shifting to whole, minimally processed meals was associated with weight loss, lower body fat, improved cholesterol, and better insulin sensitivity across two different protein-focused diets.

Researchers published a study in Clinical Nutrition reporting results from an 18-week randomized, controlled feeding trial that tested how diet quality affects metabolic health in adults aged 65 and older. The study provided all meals to 36 participants and used a crossover design in which groups followed one diet for eight weeks before switching to the other. Both diet patterns were aligned with the Dietary Guidelines for Americans (2020–2025) and differed mainly by primary protein source. A central change in both diets was a large reduction in ultra-processed food intake. Key findings: - The trial included 36 adults aged 65 and older who completed an 18-week crossover feeding study in which all meals were provided. - Participants followed two nutrient-rich diets (one with meat, one with lentils as primary protein) each for eight weeks before switching, with both diets aligned to the Dietary Guidelines for Americans. - Ultra-processed food intake fell from about 50% of daily calories at baseline to roughly 11–14% during the intervention. - Without being told to restrict calories, participants naturally consumed fewer calories and experienced weight loss and reduced body fat. - The study reported improvements in cholesterol levels and insulin sensitivity across both diet patterns, though the sample was small and not diverse. - Limitations include the small sample size, mostly white and college-educated participants from rural Midwest areas, and the relatively short 18-week duration. Summary: The study found that a major reduction in ultra-processed foods, paired with meals based on whole or minimally processed ingredients, was associated with weight loss and improved metabolic markers including cholesterol and insulin sensitivity in older adults, regardless of whether the diet centered on meat or lentils. Researchers note that larger, longer, and more diverse studies are needed to confirm these findings and assess whether the changes persist over time.