Changing your diet for just four weeks might make your body biologically younger. A new study from the University of Sydney found that older adults who ate less dietary fat or animal-based protein showed improvements in markers linked to biological aging in just one month.
The research, published in Aging Cell, looked at adults aged 65 to 75. It explored how different eating styles affected "biological age," which is a measure based on body functions rather than actual years lived. Dr. Caitlin Andrews led the study. It adds to the growing idea that diet can affect how our bodies age, even later in life.
While these findings are promising, the researchers say they are still early. More studies are needed to see if these short-term changes lead to lasting health benefits or lower risks of age-related diseases.
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Start Your News DetoxWhat Biological Age Tells Us
Scientists use "biomarker profiles" to estimate biological age. These profiles track changes in how the body works over time. They can offer a clearer picture of long-term health and how long someone might live.
The researchers checked 20 biomarkers, including cholesterol, insulin, and C-reactive protein levels. They used these to figure out biological age scores for people in the Nutrition for Healthy Living study.
The study involved 104 participants. They were randomly put into one of four diet groups. In all diets, 14% of their total energy came from protein. Two diets included both animal and plant protein equally. The other two were semi-vegetarian, with 70% of protein from plants.
Four Diets Tested
Participants in both the omnivorous (meat-eating) and semi-vegetarian groups were also given either high-fat, low-carbohydrate diets or low-fat, high-carbohydrate diets. This created four diet types:
- Omnivorous high-fat (OHF)
- Omnivorous high-carbohydrate (OHC)
- Semi-vegetarian high-fat (VHF)
- Semi-vegetarian high-carbohydrate (VHC)
The participants had a BMI between 20 and 35. They did not smoke, were not vegetarians before the study, and had no major health issues like type 2 diabetes, cancer, kidney, or liver disease. They also had no food allergies.
The OHF group, whose diet was most like what they ate before the study, did not show big changes in biological age. However, the other three diet groups showed lower biological age scores.
High-Carbohydrate Diet Showed Strongest Results
The strongest evidence for reduced biological age came from the OHC group. This group followed an omnivorous diet high in carbohydrates. Their diet was 14% protein, 28-29% fat, and 53% carbohydrates.
Researchers are not sure if these improvements are temporary. They also don't know if they will lead to long-term slowing of biological aging.
Associate Professor Alistair Senior, who oversaw the research, said longer-term diet changes are needed. This will help assess if diet changes affect the risk of age-related diseases.
Call for Longer Studies
Dr. Andrews noted that it's too early to say for sure that specific diet changes will extend life. However, this research gives an early look at the possible benefits of diet changes later in life.
She added that future research should see if these findings apply to other groups. They also need to check if the changes last or predict long-term health outcomes.
Deep Dive & References
Short-Term Dietary Intervention Alters Physiological Profiles Relevant to Ageing - Aging Cell, 2026
