Obesity increasing risk of wide range of illnesses, including brain health

Numerous studies show that obesity can do serious harm to a human’s physical and mental health, increasing the risk for a wide range of illnesses.

But too much weight on the body also can harm the brain.

Research shows obesity impacts brain health from childhood well into adulthood, affecting everything from executive function skills—the complex ability to initiate, plan and carry out tasks—to substantially raising dementia risk.

By middle age, the consequences of excess weight are substantial. Several studies have shown middle-aged adults who have a body mass index (BMI) at or above 30, which qualifies as obesity, are more likely to get dementia than their healthy-weight peers.

Yet, researchers are still teasing out how and why the extra pounds harm the brain, and whether the higher dementia risk is cumulative over a lifetime or if obesity affects the body differently at different stages of life.

Some studies trace the beginnings of the relationship between diet, weight and brain health all the way back to the womb. By toddlerhood, there's already an association between excess weight and a child's ability to control and direct behavior; integrate new information; plan; and solve problems.

One theory is that it's not just the extra weight that's causing the problem, but conditions and illnesses associated with obesity that collectively contribute to poor brain health.

"People who have obesity are more likely to have Type 2 diabetes, hypertension and high cholesterol," said Kristine Yaffe, professor and vice chair of psychiatry, neurology and epidemiology at the University of California's Weill Institute for Neurosciences in San Francisco.

There are numerous reasons to strive to maintain a healthy weight, said Mark Espeland, a professor of gerontology and geriatric medicine at Wake Forest School of Medicine in Winston-Salem, North Carolina.

"It's fairly clear that being obese in midlife is bad for the brain and much of the rest of the body, too," he said. "Preventing that from occurring is so very important."

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