Wednesday, September 23, 2026 | Edition 196 | Item #2

In fact, if you have four weeks and you’re willing to commit to a new diet, that’s enough time to lower your biological age, according to new research from the University of Sydney. The study found that adults aged 65 to 75 showed signs of lower biological age after just four weeks of changing what they ate — no exercise program or years-long overhaul required. The study, published in Aging Cell, randomly assigned 104 older adults to one of four diets varying in fat, carbohydrate, and animal-protein content, then tracked 20 biomarkers (including cholesterol, insulin, and inflammation markers) to calculate each person's biological age.

Three of the four diets produced measurable reductions in biological age; only the diet closest to participants' usual eating habits — high in fat and animal protein — showed no change. The strongest effect appeared in the group eating an omnivorous diet lower in fat and higher in carbohydrates.

Let’s, as we always do, acknowledge the limitations: it's unclear whether the changes persist, whether they lower disease risk, or whether they would hold up in other populations. Still, it's suggestive that meaningful biomarker shifts can happen fast in later life — a hopeful nudge for anyone assuming aging-related diet changes take years to show results or not sure that change is possible at all.