Recent research shows a potential link between large bellies/abdominal fat and Alzheimer's disease.  The study shows that large abdominal girth in your 40s increases your risk for developing dementia in later life.  Overall, bodyweight apparently isn't as important as shear abdominal size. 

What exactly qualifies as a large abdomen?  In this study, the researchers measured between the upper abdomen in the back of the body.  Anything over 10 inches was considered high.  The study showed that participants with normal body weights and large bellies were 89% more likely to be afflicted with dementia in later life.  Overweight participants were more than twice as likely and obese clients were three times as likely to acquire dementia.

Researchers are unsure as to why this occurs.  It does, however, provide one more incentive to get rid of that belly.