Snack cravings can strike at any time, and resisting the urge can be challenging. New research this week indicates that a specific part of your brain plays a significant role in whether or not you end up reaching for the snacks. The study enrolled 121 women who all professed to strong and frequent cravings for chocolate and potato chips. The researchers were interested in knowing how different parts of the brain might influence a person’s inclination to snack on these foods, with the ultimate goal of figuring out how certain brain circuits might influence eating habits that can lead to obesity.
In particular, they were interested in a region called the dorsolateral prefrontal cortex (DLPFC), which is a region on the front and to the side of the brain previously shown to play a role in food cravings. While its activity had been documented, no one had looked to see how people acted when this part of the brain stopped working.
Because it’s not ethical to cut out a part of someone’s brain just to see how they act without it, researchers in the past developed a magnetic brain stimulator that can be applied noninvasively called a continuous theta-burst stimulator. It excites one part of the brain to such a degree that the neurons in that area get tired and temporarily stop functioning. This then allows researchers to see how a person without that region of the brain might act. These researchers showed participants pictures of foods to stimulate cravings and then applied magnetic stimulation to the DLPFC. They then looked to see whether their cravings for high-calorie snacks changed.
The participants reported their cravings for foods like milk chocolate and potato chips increased after the stimulation. When given the option of eating dark chocolate and soda crackers next to milk chocolate and potato chips, the participants consumed more of the unhealthy foods than they had before the stimulation.
Additionally, researchers ran the participants through the Stroop test, which uses words of different colors to test a person’s ability to inhibit the activity of certain parts of their brain. The participants had less inhibitory control than they did before the stimulation. In addition, the researchers found the participants were more sensitive to the rewarding aspects of eating these sorts of foods.
What all of this means is that your cravings are a complex neurologic process that involves more than just acting on impulse. When your eyes pick up a delicious piece of chocolate, the information is interpreted by many parts of your brain involved in deciding whether or not to eat it. It seems the DLPFC helps to push you in the direction of going for the healthier option or not snacking at all by regulating the level of anticipation you feel about putting that next piece of chocolate in your mouth. It acts almost like your brain’s pessimist, whispering over your shoulder, “Hey, it’s probably not that good.”
The researchers suggest that trying to strengthen this area of the brain might also help turn down that next bag of chips. The easiest way to do that? A little exercise.