How a Big Belly Can Shrink Your Brain


If you’ve had an expanding waistline lately, your brain could pay for it later.

A study published in the journal Neurobiology of Aging associated obesity with an increased brain age later in life. The study included nearly 530 individuals, ranging in age from 20 to 87.

The participants were separated by two Body Mass Index categories: lean and overweight/obese. A lean BMI was considered to be 18.5 to 25, while overweight/obese was defined as a BMI greater than 25.

Those with an overweight/obese BMI were associated with having lower and atrophied cerebral white matter, especially for middle aged participants around the age of 40.

“The fact that we only saw these differences from middle-age onwards raises the possibility that we may be particularly vulnerable at this age,” Paul Fletcher, senior study author said in a press release. “It will also be important to find out whether these changes could be reversible with weight loss, which may well be the case.”

White matter is the tissue that connects different areas of the brain together and helps with memory. Other research has linked white matter to brain functions such as the speed at which the brain processes information. No changes were observed to the brain’s grey matter, which contains the majority of neurons.

The effect of obesity on the brain is widespread, affecting all areas, the study said. Individuals who were overweight had brains similar to those with a healthy weight who were ten years older.

Harmful proteins called cytokines were suggested to be part of the problem. Cytokines are responsible for inflammation. The study suggested that cytokine production could grow as the body’s fat content grows.

While the study didn’t investigate what harmful effects that the brain shrinkage might mean, study author Lisa Ronan said this could predict mental health issues.

“It is possible that being overweight may raise the risk of developing disorders related to neurodegeneration such as Alzheimer’s disease or dementia,” she said.

While no differences in cognitive function were found between people with lean BMIs and people without, overweight and obese individuals are at risk for many health issues. Additional studies have linked thin white matter to mental health issues such as Alzheimer’s disease.

There is hope, however, to reverse the brain’s changes from obesity. The study suggests cutting back on calories to lose weight as one way to turn things around.

“The finding that increased body mass equates to an average brain age increase of 10 years further stress the need to tackle obesity, particularly in early adult life,” the study said. “Interventions such as caloric restriction indicate the potential efficacy in preventing or amelioration normal age-related degeneration.”

Research has suggested that weight loss can improve brain function, possibly reversing the effects of weight gain on the brain.

One study went as far as to observe the brain’s activity when individuals were presented with pictures of different kinds of food in order to determine how brain function could be improved.

“We’re living in an aging population, with increasing levels of obesity, so it’s essential that we establish how these two factors might interact, since the consequences for health are potentially serious,” Fletcher said.