Skip to main content

Verified by Psychology Today


Can Your Diet Make You Stupid?

Yes. The culprit is obesity and this is what we know now.

Yes. The culprit is obesity, i.e. body fat. Recent epidemiological and clinical studies indicate that obesity is a risk factor for cognitive decline and impaired memory in adult and older humans. One recent epidemiological study concluded that by the year 2050 the number of overweight or obese Americans would increase to above fifty percent. This statistic is alarming because obesity produces chronic, low-grade, body-wide inflammation, insulin resistance and many of the same metabolic conditions that underlie the aging process itself. However, you do not have to be obese in order to suffer from the consequences of fat.

Many laboratories around the world, including my own, have documented the mechanisms that underlie how excessive body fat impairs brain function. Scientists have focused on serious degenerative changes that occur within a brain structure called the hippocampus. Normal function of the hippocampus is critical for the formation of new memories. Recent studies have reported specific abnormalities in the cellular connections and general health of cells within the hippocampus that likely underlie the memory impairments.

Not only that, it now appears that the negative consequences of obesity extend all of the way into the heart of brain cells: the DNA is altered. Specific genes that are critical for making memories no longer function appropriately. A study published this month in the Journal of Neuroscience (Vol 27, p. 1324, 2016) found that obesity induces epigenetic alterations in how the DNA in cells within the hippocampus function. What can you do about it?

You might consider either significant exercise or liposuction. Although exercise can shrink fat cells only liposuction can remove them from the body. Scientists investigated this novel question by conducting experiments on obese and normal weight mice. Daily exercising reduced belly fat and significantly restructured how their brains’ function at the cellular level leading to greatly improved memory. Standard liposuction produced results that were identical to those produced by running on the treadmill. Transplanting fat into normal, healthy weight mice lead to reduced memory performance, i.e. the rats became stupid.

Today, an overwhelming body of scientific evidence across a wide spectrum of medical disciplines strongly argues that obesity impairs overall cognitive function, accelerates the aging of the brain and, ultimately, is responsible for numerous processes that kill us. This recent study provides the mechanisms underlying the connection between obesity and impaired learning and memory abilities.

© Gary L. Wenk, Ph.D. Author of “Your Brain on Food,” 2nd Ed, 2015 (Oxford University Press)

More from Gary Wenk Ph.D.
More from Psychology Today