Scientists at the University of Sydney discovered that older people can look younger inside their bodies by changing what they eat.
In a study published in Aging Cell, volunteers aged 65 to 75 followed special diets for only four weeks. After the short period, their “biological age” – a measure of how well the body works – went down.
Dr. Caitlin Andrews led the research. She says the results are exciting but early. Bigger, longer studies are needed to prove that diet can really slow aging and lower disease risk.
What Is Biological Age?
Chronological age is how many birthdays you have celebrated. Biological age tells how healthy your cells are. Two people of the same age can have very different biological ages because of lifestyle, health, and stress.
Scientists look at biomarkers – things like cholesterol, insulin, and inflammation – to estimate biological age. In this study, they used 20 different biomarkers.
The Four Diet Plans Tested
One hundred four participants were split into four groups. Each group got a diet that gave 14% of calories from protein.
- Two groups ate meat and plants (omnivorous).
- Two groups ate mostly plants (semi‑vegetarian).
- Within each type, one diet was high‑fat/low‑carb and the other low‑fat/high‑carb.
The groups were named:
- Omnivorous High‑Fat (OHF)
- Omnivorous High‑Carb (OHC)
- Semi‑Vegetarian High‑Fat (VHF)
- Semi‑Vegetarian High‑Carb (VHC)
Which Diet Worked Best?
The OHF group, which ate a diet similar to what they usually ate, showed no change in biological age.
The other three groups all got younger biologically. The biggest drop was seen in the OHC group – a meat‑and‑plant diet that was low in fat and high in carbs (about 28% fat, 53% carbs).
Even though the changes happened fast, researchers warn we don’t yet know if they last for years.
What Comes Next?
Associate Professor Alistair Senior says longer‑term studies are needed to see if these diet tweaks can lower the risk of age‑related diseases.
Dr. Andrews adds that the findings are an early sign that eating better later in life may help the body stay younger, but more research is required.