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Researchers say obesity can increase the risk of developing Alzheimer’s disease. Milamai/Getty Images
  • Researchers say obesity, especially in middle age, can increase the risk of developing Alzheimer’s disease.
  • Experts note that obesity can also heighten the risk of other conditions, including heart disease and type 2 diabetes.
  • They say maintaining a healthy weight can be achieved through diet, exercise, sleep, and stress reduction.

Obesity might increase the chance of developing Alzheimer’s disease and losing weight may decrease the risk and slow cognitive decline, according to a study published in the Journal of Alzheimer’s Disease.

Researchers analyzed brain scans of more than 1,300 individuals and compared patterns of the gray matter of people with Alzheimer’s disease to those of healthy participants.

They also compared brain scans of people with obesity to individuals without the condition.

The researchers then created brain maps of gray matter atrophy for all participants.

The scientists reported that obesity and Alzheimer’s disease affected gray matter similarly, suggesting that both could cause the same type of neurodegeneration in the brain.

Gray matter is a major factor in Alzheimer’s disease development.

Plaques can build up in the brain and decrease the amount of gray matter, leading to a decrease in higher functioning, according to a report published in 2021.

Cognitive function, motor function, and memory decline as the gray matter shrinks.

“This study makes significant contributions to mounting evidence of the harmful effects of obesity — a multisystem disease linked to metabolic changes including direct impacts on the central nervous system — on cognition, overall brain health, and Alzheimer’s disease risk,” said Dr, Scott Kaiser, a geriatrician, and director of geriatric cognitive health for the Pacific Neuroscience Institute at Providence Saint John’s Health Center in California.

“It shows neurodegeneration (or the loss of brain cells demonstrated by cortical thinning) might be one of the key mechanisms driving this risk,” Kaiser told Healthline. “This adds to the growing body of evidence surrounding ‘modifiable’ risk factors for dementia, meaning there is a wide range of things we can do — or avoid — to keep our brains healthy and reduce our future risk of developing dementia. And when it comes to dementia, experts suggest that one-third of cases might be prevented by addressing modifiable risk factors.”

Experts say the new study strengthens previous research that links obesity to Alzheimer’s disease and points to cortical thinning, or the loss of brain cells, as one of the potential causes.

In a press release, Filip Morys, PhD, a postdoctoral researcher at the Montreal Neurological Institute in Canada and a lead author in the study, said that decreasing weight in mid-life can reduce the risk of developing Alzheimer’s and other neurodegenerative conditions.

It is obesity during the mid-life years that is most harmful, according to a report published in Frontiers in Nutrition.

“It is believed that getting to and maintaining a healthy weight can reduce the risk from obesity for dementia,” said Dr. Glen Finney, the director of the Geisinger Memory and Cognition Program and a board member of the Greater Pennsylvania Chapter of the Alzheimer’s Association.

“Mid-life obesity is one of many health risks associated with increased risk for late-onset Alzheimer’s disease, as does related health problems like diabetes. It is the most significant modifiable risk factor for dementia impacting the American population,” Finney told Healthline.

Being overweight in the mid-life years can cause numerous health issues decades later.

People who had a higher body mass index (BMI) were 2.5 times more likely to become frail earlier, according to a study published in BMJ Open. Frailty is a higher risk of falling, injuries, being hospitalized, and experiencing complications due to hospitalizations.

Obesity is considered the top modifiable dementia risk in the United States.

Being overweight affects men and women, but most women are overweight at midlife; according to the North American Menopause Society, Carrying extra weight increases the risk of developing cardiovascular disease, type 2 diabetes, high blood pressure, osteoarthritis, and some types of cancer.

Some factors contributing to weight gain during mid-life include:

  • Slowing metabolism
  • Lean body mass decreases and body fat increases – fat burns fewer calories than muscle does
  • Decrease in physical activity

Preventing obesity and maintaining a healthy weight involves several strategies, according to Harvard Health:

  • Increasing healthy foods in your diet, including whole grains, fruits, vegetables, healthy fats, and proteins
  • Decreasing unhealthy foods with refined grains and sugars, white potatoes, red meat, and processed meats
  • Increasing physical activity
  • Decreasing the length of time you sit during the day
  • Improving sleep
  • Reducing stress