Important cognitive brain regions are smaller in older obese people than fit ones, scientists have found. Shrinking brains are tied to dementia, so the discovery fuels the notion that obesity can raise the risk of the cognitive disorder, New Scientist reports. In a review of 94 brain scans, subjects with higher body mass indexes had memory and planning areas that appeared particularly shrunken.
The brains of the 51 overweight people were 6% smaller than those of their leaner peers, while the brains of the 14 obese people were 8% smaller. “The brains of overweight people looked eight years older than the brains of those who were lean, and 16 years older in obese people,” said a researcher. But another scientist says we don't yet know "which is the chicken and which is the egg," pointing out that the shrunken frontal and temporal lobes control eating behavior and metabolism, which could trigger weight gain.