High Intensity Exercise Helps Fight Cravings for Junk Food

Though people who exercise frequently may need to consume more calories, a recent study shows that high-intensity workouts could also help them make healthier choices.  

"The key aim of our research was to examine the brain's responses to high and low calorie food following a period of acute exercise," said Dr. Daniel Crabtree, who is from the University of Aberdeen's Rowett Institute of Nutrition and Health, via Medical Xpress. "Our focus was on a region of the brain called the insula - commonly referred to as the 'primary taste cortex'. Activation in this region is increased in the anticipation of foods, and when consuming foods that we perceive as being pleasant."

For the study, nutritionists examined the relationship between high-intensity exercise and appetite. Researchers recruited 15 healthy men who were required to run for one-hour at a certain speed and used magnetic resonance imaging (fMRI) in order to better record the participants' appetite in response to the brain. During the fMRIs, researchers showed the men healthy and unhealthy food options. For a second visit, they also had the participants rest before looking at the images. Unhealthy food options included things like pizzas, burgers and doughnuts, while healthier ones consisted of grapes, strawberries and carrots.

Researchers found that the brain response measured by activity levels of the insula were reduced when the men looked at pictures of high-calorie foods. However, activation in these regions increased with the participants saw images of healthy food.

"We also asked people to rate their hunger levels and took blood samples to analyze two hormones relating to appetite stimulation and suppression," Crabtree said. "After running the volunteer's feelings of hunger were suppressed, and the appetite hormone analysis showed us that levels of the appetite stimulating hormone were reduced whilst levels of the appetite suppressing hormone were increased."

The researchers believe that since the insula is linked to thirst, people may pick the low-calorie options because they have higher water content. Thus, by eating certain types of food, people can satisfy their exercise-induced thirst.

"Our study focused on brain activity in healthy, lean volunteers. Further studies, encompassing volunteers who are overweight or obese, and employing different workouts and intensities are required in order to formulate how this link between brain activity and exercise could be best used in the development of advice for healthy weight loss," Crabtree concluded.

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More information regarding the study can be found via the American Journal of Clinical Nutrition.