Why Is It So Hard to Resist Tempting Foods?

There may be a neural basis for your cravings

Posted Jun 24, 2019

If you’re concerned about your weight you probably have foods that are almost impossible to resist. When you see the food, or even a picture or a commercial for it, your thinking becomes preoccupied with that food. You crave it and you can’t get it out of your mind. Rationally, you know that you don’t need it and that it probably won’t provide that much enjoyment, yet you won’t be happy until you get it. It’s likely that this sensitivity to food cues causes unnecessary eating that can contribute to weight gain.

A recent study suggests that there is a  physiological process that is responsible for heightened sensitivity to food cues that trigger cravings. Psychologists at Dartmouth had female college students weighed and then they had brain scans using functional magnetic resonance imaging (fMRI). The brain scans occurred while they were viewing images of neutral scenes (e.g., animals, people) and images of appetizing foods. The scan analysis focused on the nucleus accumbens while the participants were viewing the images.

Eating pleasure is not just a conscious thought but is mediated by deep brain structures including the nucleus accumbens. The researchers hypothesized that there would be a relationship between greater activity in the nucleus accumbens while viewing pictures of food and weight gain. Participants who had less response to the pictures would be less likely to gain.    

Six months after the initial scan the participants returned to the lab for a follow-up weighing. As predicted there was a relationship between reward-related brain activity and subsequent weight gain. Greater activity in the nucleus accumbens when viewing food images predicted weight gain six months later. 

This process doesn’t require exposure to the actual food and can occur unconsciously. You may not always be aware of the triggers that cause the craving. Pictures, TV commercials and other cues can increase the likelihood of craving and eating.

The findings demonstrate that exposure to food cues increases activity in the brain’s reward centers. There’s a biological basis for cravings, they aren’t just a matter of “will power.” Higher-order cognitive functions like rational thinking may help to reduce cravings but stress weakens the cortex’s (the more advanced part of the brain) control of behavior. Reducing stressors and understanding the biological origins may help to curb cravings.

References

Demos, K. E., Heatherton, T. F. & Kelley, W. M. (2012). Individual differences in nucleus accumbens activity to food and sexual images predict weight gain and sexual behavior. Journal of Neuroscience, 32, 5549-5552.