There are three areas of the brain that are thought to influence eating decisions. If these areas are over- or underactive, people might have a difficulty controlling the urge to eat. In a recent Nutrition Journal study, researchers sought to learn more about how our brain impacts food choices.
Background
There are three areas of the brain that affect our food choices:
- The first is the striatum system. When you observe some kind of external cue like food, this system is driven by the rewards of consuming that food. This neural system might be overactive in people who have trouble with self-control when presented with delicious food.
- The second neural system is a combination of the decision and impulse control systems. These areas allow us to postpone gratification for greater long-term goals, such as health. In a person who overindulges in food, decision and impulse control would be underactive, preventing them from making the smarter decision.
- Finally, there is the insula system. This system is involved in the homeostasis of your body, which is disturbed when you eat. The insula system also regulates self-awareness, the conscious aspects of yourself. This, too, may be suppressed when overeating is an issue, which would result in the lack of sensations of satisfaction.
Study Design
Using an MRI, thirty young people ranging from fourteen to 22 years old were examined. All the participants answered a questionnaire about their diet, and they took an IQ test to factor out intelligence as the primary difference in food choices.
The subjects were shown pictures of various kinds of foods, some appetizing and some not. The foods were divided into low- calorie options, like celery and broccoli, as well as high-calorie options, like cookies and potato chips. The researchers examined two of the above neural systems (the striatum system and decision and impulse control system) on each participant while the subjects were looking at these foods.
In addition to viewing the images, the participants were required to take an action. They were told to press a button as fast as possible when presented with a high-calorie food in one test or a low-calorie food in the other. This task demonstrated their ability to respond to appetizing food that could override their food choices.
Results
The participants pressed the button more often than they were instructed to for high-calorie foods, indicating they had a conditioned response to favor these foods. The more prone to overeating they were, the greater the odds were that they would press the button correctly when viewing high-calorie foods.
The striatum was also more active when presented with high-calorie foods. The greater the body mass index (BMI) of the participant, the stronger this response. The right striatum, which controls the rewards that enforce habits, experienced a particularly powerful response.
Finally, the impulse and decision-making systems were more active when the participants were supposed to abstain from hitting the button for high-calorie foods. Thus, their impulse control was most active when they were not supposed to select the foods they found appetizing.
The researchers pointed out that while these brain systems might alter our food choices, it isn’t yet clear if they are genetically wired this way, or if these decisions are the result of years of habitual overconsumption of food. Either way, now we are armed with more information about how we choose the foods we eat.
References:
1. Qinghua He, et. al., “Poor ability to resist tempting calorie rich food is linked to altered balance between neural systems involved in urge and self-control,” Nutrition Journal 2014, 13:92
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