Diet Not Working? Your Brain Could Be the Reason

The following information is used for educational purposes only.


Your Brain on Food

How chemicals control your thoughts and feelings.

by Gary Wenk, Ph.D.



Diet Not Working? Your Brain Could Be the Reason


Lacking prefrontal lobe willpower may cause obesity


Everyone likes to eat. Why? Your brain rewards you with a deep and pleasant feeling of satisfaction when you eat. This ensures that you'll eat again and that you'll have children who will pass on your love-to-eat genes. Your brain likes it when you eat and makes you feel happy because if you eat your brain will continue to live. Your brain likes it when you eat.

How does your brain find out that you've eaten something? Your body sends your brain several different signals that communicate the presence of food in your stomach and intestines. Your brain also receives signals from your body's fat cells in order to know how much energy is stored for future use. It is in your brains best interest that you have plenty of stored energy, i.e. fat.

The most important signal your brain receives to inform it that you've just eaten is a dramatic rise in the level of sugar in your blood. When sugar sensors in the feeding centers of your brain notice the increase in sugar in the blood your brain rewards you with very positive feelings - we've all felt it and it's wonderful.

The brain now knows that it has all the calories and nutrients that your body will need to survive until the next meal. For normal weight people this sugar signal is enough to convince you to stop eating - you've had enough. For obese people, this signaling process is not working correctly. A recent study published by scientists working at the New Jersey Medical School and Yale University in the Journal of Clinical Investigation (September, 2011) discovered that the ability of blood sugar to stop obese people from continuing to eat even when they're full, even when they're well aware that they've eaten a lot of food already, is simply missing. This might be why some people find it so difficult to stop eating at holiday buffet tables or all-you-can-eat restaurants.

The problem is that the prefrontal cortex, whose job usually is to activate your willpower to back away from high calorie foods after you've had enough, largely turns itself off in obese people. The way this process normally works is that when your blood sugar levels are low because you've not eaten recently, your prefrontal cortex turns itself off and your food reward centers turn themselves on. After a meal, your prefrontal cortex turns itself on and your food reward centers turn themselves off. Thus your willpower returns and your drive to eat is gone.

The tendency to obesity is inheritable; possibly, so is this misbehavior by the prefrontal cortex. Therefore, the best advice for people whose prefrontal lobes refuse to do their job is to avoid going near buffet tables or all-you-can-eat restaurants.

© Gary L. Wenk, Ph.D. Author of Your Brain on Food (Oxford, 2010)