That Extra Weight May Be Aging Your Brain, Study Finds

Brain health is imperative for longevity and healthspan, which is why cognitive decline has become a serious area of concern. In addition to affecting quality of life, including one’s ability to cook, clean, or drive, it’s often a precursor to severe cognitive disorders or Alzheimer’s disease over time. With that, a recent study suggests that watching your weight isn’t just a great way to manage your health; it could also help slow cognitive decline.

Weight gain and your brain

While some cognitive changes are a natural part of getting older, these changes are relatively mild in healthy adults.

Yet, some of these changes are more severe, which is why Alzheimer’s disease-related dementia (ADRD), the most prevalent form of dementia, remains one of the leading causes of death in the US, and just over 6 million US adults aged 65 or older are estimated to be living with dementia, with this number potentially rising to over 11 million by 2040.

Fortunately, while researchers work to find a cure for the condition, they have identified factors that may help prevent or even delay cognitive decline and the onset of dementia, and weight has been identified as such. For instance, one 2025 Chinese study identified a negative link between BMI and cognitive impairment, with a higher BMI linked to lower cognitive impairment risk, especially among overweight people.

Researchers more recently examined the link between BMI and declines in memory, overall cognitive performance, and executive functioning – abilities essential for everyday living.

BMI and cognitive health

For this specific study, researchers analyzed data from a nationally representative study that tracked more than 8252 adults over age 50 for 24 years, and also examined their BMI, which was calculated as weight/height2 using self-reported height (m) and weight (kg).

According to the findings, published in the Journal of Neurology, there was an association between body weight and cognitive health, with each point increase in BMI linked to a faster rate of cognitive decline. The study also found that the effects were more pronounced in adults older than 65.

Yet, despite the findings, the researchers also noted that managing body weight may help slow down cognitive decline,

“We found that if people managed their weight, they could significantly lower their rate of cognitive decline in just two years.” – Suhang Song, the study’s lead author and an assistant professor at the University of Georgia’s College of Public Health

“That makes BMI one of the most easily modifiable risk factors when it comes to aging well.”

How does weight affect the brain?

While scientists are still determining how exactly excess weight may impact cognitive health, there are a few theories.

For one, a 2020 study found that weight gain reduces blood flow to the brain, and slower blood flow to the brain is associated with several neurological and cognitive issues.

Excess weight has also been found to promote inflammation, which triggers other biological mechanisms resulting in brain cells shrinking.

Managing weight for better health

Granted, the aforementioned study does not establish that excess weight directly causes cognitive decline. Also, some experts do not believe that BMI provides a complete picture of obesity, with some even considering it to be a biased method, and that waist measurements are a better alternative. Nonetheless, this doesn’t negate the fact that weight management is a vital aspect of good health.

“There are no cures for dementia,” Song said, “which is why it is critical to identify and address any modifiable risk factors we can find to prevent it.”

Since the study has identified weight as a modifiable factor, here are a few ways in which one can better manage their weight;

1. Try mindful eating: This style of eating encourages one to be more present during their meals, paying closer attention to their meal and dietary habits.
2. Enjoy healthier snacks: Snacking can lead to both weight gain and weight management, but it’s all about what you’re snacking on. Pick nuts, seeds, and fruits, as these options are less likely to lead to weight gain.
3. Eat enough fruits and vegetables: If you’re concerned about weight loss, it would be advisable to include more produce in your diet, as it will fill you up with essential vitamins and minerals instead of fat and calories.
4. Pack on the protein: Including more protein in your diet, such as quinoa, fish, chicken breasts, lentils, legumes, and almonds, can help prevent muscle loss, as well as encourage weight loss, as it helps you feel fuller for longer.
5. Get enough sleep: It’s important to get at least 7–9 hours of sleep each night. If you’re struggling to achieve this, try using essential oils, minimizing light in your bedroom, and avoiding using your phone or watching TV before bed.
6. Lift weights: Strength training not only helps reduce body fat, but also boosts your metabolism, which we know is great for weight loss.
7. Manage your stress levels: Stress increases both appetite and cravings for sweet and fatty foods, which then leads to weight gain. To manage stress levels, try meditation, reading your favorite book, watching your comfort film, or reaching out to a confidante.

Want to know more?

Made from fermented apples and naturally high in acetic acid, apple cider vinegar (ACV) is known as the ultimate health elixir, thanks in part to its antibacterial properties, which offer a range of health benefits, which may include weight loss. A shot of apple cider vinegar a day may be exactly what you need to lose some weight and slim down your waistline.

References

Amen, D. G., Wu, J., George, N., & Newberg, A. (2020). Patterns of Regional Cerebral Blood Flow as a Function of Obesity in Adults. Journal of Alzheimer’s Disease. https://doi.org/10.3233_JAD-200655

Chen, J., Zhang, J., Wang, H., Zhu, H., Fu, J., Li, C., Zhang, Q., Xia, X., Ma, H., Liu, J., & Du, X. (2025). Obesity paradox in cognitive function: A longitudinal study of BMI and cognitive impairment in older adult Chinese population. Frontiers in Aging Neuroscience, 17, 1543501. https://doi.org/10.3389/fnagi.2025.1543501

National Bureau of Economic Research (2025). Coordinating center on the economics of alzheimer’s disease and alzheimer’s disease-related dementias: Prevention, treatment, and care. [online] NBER. Available at: https://www.nber.org/programs-projects/projects-and-centers/ADRD?page=1&perPage=50

National Institute of Neurological Disorders and Stroke. (2025). Focus on alzheimer’s disease and related dementias. [online] Available at: https://www.ninds.nih.gov/current-research/focus-disorders/focus-alzheimers-disease-and-related-dementias

Qianhui Xu, Sung, M.H., Chen, Z., Rajbhandari-Thapa, J., Bagwell Adams, G., Mahmud Khan, M., Song, S., Shen, Y., Song, X. and Song, X. (2026). Extra weight may be aging your brain faster than you think. Journal of Neurology, [online] 273. Available at: https://link.springer.com/article/10.1007/s00415-026-13696-2