Obesity May Accelerate Brain Aging, Researchers Uncover Concerning Association - Video

Could carrying excess weight make your brain age faster? A new study suggests that adults with a higher body mass index (BMI) may experience faster declines in memory and thinking abilities, while managing body weight could potentially help slow cognitive deterioration.

Published in the Journal of Neurology, the study conducted by researchers at the University of Georgia investigated the relationship between body weight and cognitive function during ageing.

Researchers analysed data from more than 8,200 adults aged 50 years and older who were followed for 24 years as part of a nationally representative study.

The researchers examined changes in BMI alongside cognitive abilities, including memory, overall cognitive performance and executive functioning.

Executive functioning involves mental skills required for planning, decision-making, concentration and organising everyday activities.

The findings revealed that participants with higher BMI experienced faster declines in memory and overall cognitive performance over time.

Importantly, each one-point increase in BMI was associated with a greater rate of cognitive decline.

The association was particularly pronounced around the eighth year of follow-up, with adults aged over 65 showing stronger relationships between higher BMI and worsening cognitive performance.

Researchers also suggested that improvements in weight management could be associated with slower cognitive decline, with potential differences becoming noticeable within approximately two years.

Several biological mechanisms may help explain the association.

Excess body weight can contribute to chronic inflammation, insulin resistance and impaired blood circulation, which may influence brain function and increase vulnerability to cognitive impairment.

However, the study was observational and could not establish that higher BMI directly causes faster brain ageing or that weight loss necessarily prevents cognitive decline.

Researchers also acknowledged that BMI alone does not fully capture body fat distribution or overall metabolic health.

Further research is needed to determine whether targeted weight-management interventions can directly reduce the risk of cognitive decline and dementia.

REFERENCE: Qianhui Xu, et al.; Association between cumulative average BMI and cognitive decline: a 24-year cohort study. Journal of Neurology, 2026; 273 (2) DOI: 10.1007/s00415-026-13696-2