Active Voice: Might Exercise Decrease Our Susceptibility to Overconsumption?
By ACSM Member Kristine Beaulieu, Ph.D., R.D.

Kristine Beaulieu
Exercise is often portrayed as counterproductive for weight management, with some reports stating exercise increases appetite and food cravings for high-fat or sugary foods. However, while there is a large, inter-individual variability in body fat response to exercise training, long-term physical activity has been shown to lead to clinically meaningful reductions in body weight. Also, as highlighted in this 2009 ACSM position stand, physical activity may be one of the most important behaviors for prevention of weight regain.

The physiological and neurocognitive mechanisms that underpin the relationship between exercise and eating behavior are complex. It has been proposed that physical activity impacts appetite control through two processes: an increased drive to eat due to greater energy requirements and an enhanced satiety response to food. These two processes allow more accurate “matching” of energy intake to energy expenditure, because of stronger hunger and satiety signals.

While there is accumulating evidence for these improvements in homeostatic appetite control, little is known about how aerobic exercise influences food reward and behavioral susceptibility to overconsumption. Food reward is comprised of two components: liking and wanting. Liking is the pleasantness of food, while wanting is the motivational, often implicit, desire to eat food. One method for assessing food reward is the Leeds Food Preference Questionnaire. This computerized task uses an array of validated food images that differ in fat content (high/low) and taste (sweet/savory). Subjective ratings and a forced-choice task provide measures of explicit liking and implicit wanting, respectively. Eating behavior traits include psychological or cognitive tendencies that increase the susceptibility to overconsumption, such as disinhibition of eating and binge eating.

In a study published in the April 2020 issue of Medicine & Science in Sports & Exercise®, we examined the impact of 12 weeks of supervised moderate-to-vigorous exercise (500 kcal/day, five days/week) in 46 individuals with overweight/obesity on food reward and eating behavior traits. Healthy inactive volunteers aged 18-55 years and with a body mass index between 26.0-38.0 kg/m2 were recruited from the local community. Changes in all outcomes were compared to 15 similar individuals in a non-exercising control group. We found that exercise led to a reduction in wanting, with no change in liking, high-fat relative to low-fat foods. Binge eating scores also improved, which correlated to changes in body fat. The mechanisms for these effects remain to be elucidated. Future research is needed to better understand the neurocognitive effect of exercise and its relationship with food reward and eating behaviors.

Our findings suggest that food reward does not counteract the benefit of exercise for obesity management. Rather, exercise appears to accompany positive changes in food preferences in line with improvements in appetite control and small, but clinically meaningful, reductions in weight and waist circumference. Taken together with previous work on the impact of physical activity on appetite, exercise training generally enhances appetite control through an impact on homeostatic and hedonic processes occurring around an eating episode. It has an improved effect on more enduring eating behavior traits promoting overconsumption.

About the author:
Kristine Beaulieu, Ph.D., R.D., is a research fellow and dietitian in the Appetite Control and Energy Balance Research Group at the University of Leeds in the United Kingdom. She investigates the impact of physical activity and diet on the mechanisms of appetite control. Dr. Beaulieu has been a member of ACSM since 2013. Connect with Dr. Beaulieu at k.beaulieu@leeds.ac.uk or on Twitter @KristineB_RD.

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