Why Belly Fat Is Bad for Your Brain

The news just keeps getting worse for the potbellied. Not only does belly fat put you at risk for diabetes and heart disease, but a study suggests it may make you lose your mind as well.

It seems that your sagittal abdominal diameter, or SAD—your belly size—is associated with risk of dementia in old age, according to a recent study in Neurology. The bigger the SAD in your 40s, the greater the chance you’ll have mental deterioration in old age.

How much of a chance? If you’re overweight or obese and don’t have a potbelly, your dementia risk is 1.8 times higher than that of your slender peers. If you are overweight or obese and do have an apple shape, your risk is 2.3 to 3.6 times greater than that of wasp-waisted folks.

Overall, about 15% of the people in the study developed dementia, as
did 21% of people with potbellies. The 6,583 participants had their
midsections measured in the late 1960s and early 1970s, when they were
40 to 45 years old, and then again around age 70 by researchers at
the Kaiser Permanente Division of Research in Oakland, California.

So why is belly fat so bad for your brain? Although it makes up less
than 5% of total body fat, belly or visceral fat is nestled around
the heart, pancreas, and other organs, according to Tongjian You,
PhD, an assistant professor in the department of exercise and
nutrition sciences at the University at Buffalo in Buffalo, New York.

And it’s different from other types of fat because it produces all
kinds of inflammatory compounds that can contribute to heart disease,
diabetes, and now, potentially, dementia.

"Visceral fat releases higher amounts of those cytokines, especially
interleukin 6, that cause cardiovascular disease and diabetes," says
Dr. You, who was not involved in the dementia study. But what’s the
brain connection? "Inflammation is a contributing factor to dementia,
so that’s a reasonable link," he says.

You don’t have to be wearing gigantic pants to be potbellied. The American Heart Association’s guideline
for a too-generous waistline is 102 centimeters (40 inches) or more for
men and 88 centimeters (34.5 inches) for women, says Dr. You. It’s not
clear if diet alone is enough to whittle your abdominal fat. From his
own and other research, he believes that exercise is important for shrinking belly fat, particularly in those who are relatively lean.

"If a person is overweight and obese, that person should change both
diet and exercise," he says. However, if someone is lean or just a
little overweight and has excess weight in their midsection,
"exercise may be the perfect treatment."