Does Eating a High-Fat Diet Damage Your Brain?

When you take a bite of that pepperoni pizza with extra cheese are you damaging parts of your brain that control weight? That's what a new study carried out at the University of Washington suggests. Their research shows that eating a diet high in fat injures a portion of the brain that controls weight, and this may be one explanation for obesity.

Do High-Fat Diets Permanently Change Your Brain?

It would be nice to think you could enjoy a hot fudge sundae with whipped cream without doing lasting damage to your waistline, but a recent study carried out on rodents raises concerns that eating high-fat foods may change the way your brain responds to food. We already know that eating fatty foods causes temporary blood vessel inflammation, but that inflammation is thought to be short-lived. This study calls that into question by suggesting there may be permanent damage to areas of the brain that control weight as a result of overindulging in fatty foods.

When researchers fed rodents a high-fat diet and looked at their brains, their brain tissue showed inflammation and scarring within 24 hours after eating fatty foods. The area most affected was the part of the hypothalamus that controls appetite. If you stimulate that particular portion of the brain, it causes the sensation of hunger.

The hypothalamus also receives feedback from the rest of the body through the appetite hormone leptin. Leptin is produced by fat cells. When there are adequate fat stores, fat cells release leptin, and leptin feeds back to the hypothalamus of the brain. This sends the signal that there are enough fat stores, and it's okay to turn off the desire to eat. If this area is scarred, this feedback mechanism no longer works, and it could lead to overeating and obesity.

Of course, there's not enough evidence to say this applies to humans too, but some experts believe this finding explains the "set point" theory. When an obese person loses weight, they typically regain it over a period of months to years and return to their set point weight. Does this happen because nerves in the brain that regulate energy balance and body weight are damaged? No one knows for sure.

What Does This Mean?

Watch how much fat you're getting in your diet, but don't go overboard based on a single study. Your body needs a certain amount of fat to supply two essential fatty acids called linoleic acid and alpha-linolenic acid. Plus, there are good fats like monounsaturated fats in olive oil and omega-3 fats in fatty fish and bad fats like trans fats and saturated fats. It's not clear whether good fats and bad fats affect appetite control in the same way. There's another reason not to become fat phobic. When you adopt a low-fat diet, you end up replacing the fat with carbs. If the carbs you choose are high-glycemic carbs, the insulin surge may be just as unhealthy as a high fat diet.

The bottom line? Eat healthy fats in moderation, and avoid trans fats and saturated fats. Healthy fats have their place in a well-balanced diet if you don't take it to the extreme.On the other hand, watch out for those hot fudge sundaes.

References:

J Clin Invest. 2012;122(1):153-162. doi:10.1172/JCI59660.