Fat and the Brain

Olivia Judson writes in the NYT about the effects of obesity on the brain.  Hint: it ain't good.

Being fat is bad for your brain.

That, at least, is the gloomy conclusion of several recent studies. For example, one long-term study of more than 6,500 people in northern California found that those who were fat around the middle at age 40 were more likely to succumb to dementia in their 70s. A long-term study in Sweden found that, compared to thinner people, those who were overweight in their 40s experienced a more rapid, and more pronounced, decline in brain function over the next several decades.

Consistent with this, the brains of obese people often show signs of damage. One study of 60 healthy young adults (in their 20s and 30s) found that the fatter members of the group had significantly lower gray-matter densities in several brain regions, including those involved in the perception of taste and the regulation of eating behavior. A study of 114 middle-aged people (aged between 40 and 66) found that the obese tended to have smaller, more atrophied brains than thinner people; other studies have found similar results.

Brains usually atrophy with age, but being obese appears to accelerate the process. This is bad news: pronounced brain atrophy is a feature of dementia.