As you gain weight, your brain gets smaller. Even worse, the brain drain seems to occur in areas vital for decision−making and memory. That's the take−home lesson from a study recently performed on the elderly. Obese and overweight study subjects had significantly less brain tissue than their normal weight counterparts.

Obese subjects had 8% less brain tissue, while overweight subjects had 4% less brain tissue.

...[T]he brains of obese people looked 16 years older than their healthy counterparts...

This is the first study offering physical evidence that directly links weight gain to brain degeneration. The study doesn't prove that obesity causes brain loss; it just shows a Correlational study. But it does suggest it.

Paul Thompson is a professor of neurology at UCLA and senior author of the study. Comparing brain images of study participants, Thompson said that the brains of obese people looked 16 years older than their healthy counterparts, while those of overweight people looked eight years older.

"That's a big loss of tissue and it depletes your cognitive reserves, putting you at much greater risk of Alzheimer's and other diseases that attack the brain," said Thompson. "But you can greatly reduce your risk for Alzheimer's, if you can eat healthily and keep your weight under control."

The researchers compared brain images of 94 subjects who were all in their 70s. None of the subjects had dementia or other cognitive impairments. Subjects were followed for five years and any who did develop symptoms of cognitive decline were dropped from the study.

While all people lose brain tissue as they age, obesity seems to accelerate the process.

Mitchell Roslin is chief of obesity surgery at Lenox Hill Hospital in New York City. Roslin sees the study results as just another notch on obesity's belt: "Obesity affects every system in your body. The bottom line is that an obese, sedentary person is going to have a breakdown of every organ system. We are what we eat and we eat too much."

This study offers yet another example of how the body affects the mind. And one more good reason to make the effort to maintain a normal weight.

The article detailing the study was published in the online, August 6th edition of the journal Human Brain Mapping. Cyrus A. Raji, a medical student at the University of Pittsburgh School of Medicine, was lead author.