Increasing body weight is associated with decreased activity and blood flow in the brain, according to a new imaging study. 

The study team analyzed more than 35,000 neuroimaging scans from more than 17,000 study participants. They found a progressive pattern of reduced blood flow tied to higher body mass index in “virtually all regions of the brain.” The brain changes included areas known to be vulnerable to Alzheimer’s, reported lead author Daniel Amen, M.D., of Amen Clinics, Costa Mesa, CA, a provider of diagnostic brain scans.

In brain scans, low cerebral blood flow is the No. 1 sign that someone will develop Alzheimer’s disease, according to the investigators.  

“This study shows that being overweight or obese seriously impacts brain activity and increases the risk for Alzheimer’s disease as well as many other psychiatric and cognitive conditions,” Amen said.

The results reveal the need to make targeted interventions available for people with obesity, he added. “[B]rains can be improved when you put them in a healing environment by adopting brain-healthy habits, such as a healthy calorie-smart diet and regular exercise,” Amen concluded.

“Acceptance that Alzheimer’s disease is a lifestyle disease, little different from other age-related diseases … is the most important breakthrough of the decade,” said George Perry, Ph.D., from the University of Texas and editor-in-chief of the Journal of Alzheimer’s Disease, where the study was published. “This [study] is a major advance because it directly demonstrates how the brain responds to our body.”

Weight has continued to be a problem for Americans and their health. According to the latest figures from the Centers for Disease Control and Prevention, 72% of Americans are overweight, and 42% are obese.