Diet changes shifted biological-age markers in 4 weeks—but did not prove aging was reversed

News summary

ScienceAlert covered an Aging Cell randomized trial in which 104 adults aged 65–75 followed one of four controlled diets for four weeks, with all meals provided. Researchers used the Klemera–Doubal Method to combine clinical and metabolic biomarkers into an age-like physiological index and tested whether protein source and fat-to-carbohydrate composition shifted that measure.

Compared with the omnivorous high-fat reference diet, the omnivorous lower-fat/higher-carbohydrate diet showed about a 3.5–4.1-year lower calculated δAge after adjustment. Some semi-vegetarian diets also showed reductions in one model or borderline effects. These values reflect shifts in a biomarker-derived index, not literal reversal of several years of aging.

The notable point is that age-related physiological markers can respond quickly to dietary change. The trial does not show that “more carbohydrate” is generally anti-aging: food quality, saturated fat, fiber, protein source, and the overall dietary pattern changed together, and carbohydrate sources were largely whole and minimally processed.

The intervention lasted only four weeks, the sample was small and relatively healthy, and the main outcome was a calculated physiological biomarker index rather than disease, disability, or lifespan. It is unknown whether the changes persisted after the diet ended or translate into lower long-term disease risk.