24-Year Study Finds Unexpected Link Between Body Weight and Brain Aging

Being overweight can impact more than just your physical health. A new study from the University of Georgia suggests people with a higher body mass index, or BMI, may experience faster declines in memory, concentration, and other thinking skills as they age.

The study published in the Journal of Neurology tracked more than 8,200 adults over the age of 50 for 24 years. Higher BMI was linked to faster cognitive decline, leading researchers to wonder whether controlling body weight might help maintain brain health late in life.

They found that cognitive decline was more rapid with every one-point increase in BMI. Participants had worse memory, overall cognitive performance, and executive function, which includes skills such as planning, organizing tasks, and making decisions.

The association was particularly strong in adults over 65. The researchers also found that the relationship was strongest at the eighth-year measurement of the study.

The findings suggest controlling body weight may slow cognitive decline, with benefits possibly seen in as little as two years. But the study does not prove that weight loss itself directly prevents memory problems or other age-related changes in thinking.

Lead author Suhang Song, an assistant professor at the University of Georgia’s College of Public Health, said the findings point to a potential benefit of weight management for maintaining cognitive health.

Researchers have a number of theories about how carrying too much weight might affect the brain. Obesity can lead to chronic inflammation, poor blood circulation, and insulin resistance. These processes can have long-lasting effects on brain function, although the exact mechanisms underlying their association are still being studied.

BMI has its own limitations as a measure of health. It does not differentiate between muscle and fat, nor does it consider where body fat is located.

The results suggest that weight management can be part of healthy aging, but must be interpreted with caution. Higher BMI is associated with cognitive decline, but that doesn’t mean one causes the other. More research is needed to determine whether weight loss itself can slow cognitive decline over the long run.

This story was originally published by Men’s Journal on Nov 2, 2026, where it first appeared in the Health section. Add Men’s Journal as a Preferred Source by clicking here.