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Unveiling the Intricate Connection Between Obesity and Alzheimer's-Like Brain Changes

Dr. Craig Smith, MD

4 Min read

Recent research conducted by scientists at the Montreal Neurological Institute-Hospital of McGill University sheds light on the fascinating parallels between obesity and Alzheimer's disease (AD) in terms of brain atrophy patterns. This study, which delves into the potential cognitive consequences of being overweight, uncovers striking similarities in the thinning patterns of brain regions associated with learning, memory, and judgment. In this exploration, we delve into the implications of these findings and their potential impact on cognitive health.

Obesity's Impact on Brain Structure:

A comprehensive analysis of brain scans from over 1,300 participants, a collaboration between McGill University and two large health databases, the U.K. Biobank and the Alzheimer’s Disease Neuroimaging Initiative, reveals a connection between obesity and changes in brain structure. By directly comparing brain scans of obese individuals with those of Alzheimer's patients, researchers identified significant thinning in the cerebral cortex—a region crucial for higher brain functions.

The Study's Methodology:

The research team examined brain imaging data from 341 Alzheimer’s patients, 341 obese individuals (with a BMI of 30 or more), and 682 healthy participants. The focus was on identifying similarities in brain atrophy patterns caused by obesity and Alzheimer's disease. The results, published in the Journal of Alzheimer’s Disease, unveiled striking parallels in the thinning patterns of specific brain regions, particularly in the right temporal and left prefrontal cortex.

Potential Mechanisms Behind Brain Thinning:

The study suggests that the brain thinning observed in both obesity and Alzheimer's could be attributed to several factors. One hypothesis points to obesity-related inflammation, hypertension, or diabetes triggering changes in the brain, subsequently leading to the neurodegeneration found in Alzheimer's. Another potential driver could be insulin and leptin resistance, hormones that typically protect neurons but may malfunction in the context of obesity. The study also considers the possibility that the observed correlation may be coincidental, with obesity and Alzheimer's-related brain thinning being unrelated phenomena.

Cognitive Implications and Neuroprotection:

While cognitive tests administered to obese participants did not reveal significant deficits, the study emphasizes the importance of understanding subtle changes related to the observed brain thinning. Researchers posit that weight control, particularly in midlife, could serve as a neuroprotective measure, potentially lowering the risk of cognitive decline and dementia.

The Significance of Midlife Weight Management:

The study's first author, Filip Morys, emphasizes the potential impact of midlife weight management on brain health. While the target weight for cognitive protection remains uncertain, Morys suggests that moving closer to a healthy weight could slow cognitive decline. The findings underscore the need for further research to explore the precise mechanisms linking obesity and Alzheimer's-like brain changes.

Building on Existing Knowledge:

This research builds upon existing literature establishing obesity as a significant factor in Alzheimer's. The authors highlight that cortical thinning might be a potential risk mechanism, reinforcing the established understanding of obesity as a multisystem disease affecting not only the central nervous system but also respiratory, gastrointestinal, and cardiovascular systems.


In conclusion, the study from McGill University offers valuable insights into the intricate relationship between obesity and Alzheimer's-like brain changes. The observed similarities in brain atrophy patterns underscore the importance of weight management, particularly in midlife, as a potential avenue for neuroprotection. As research in this field progresses, understanding these connections may pave the way for targeted interventions to mitigate the cognitive risks associated with obesity.

About the Author

In 1984, Dr. Craig Smith founded Lifesource. As a coach, he's worked with world-class athletes and guided thousands towards successful weight loss. Driven by a desire to elevate his understanding of the human body, he returned to the rigors of medical school in his 50s, achieving his goal of becoming a physician at 56. Now in his 60s, Dr. Smith leads by personal example, continuing to inspire, educate and empower individuals from all walks of life to achieve their health and fitness goals. If you wish to train and diet online with Dr. Smith, hear his message and schedule a 45-minute consultation on the New You page.