A recent story in Time Magazine made a bold statement by proclaiming that while exercise and physical activity may improve physical and mental health, it may not help you lose weight. As the author acknowledges, there are a number of reasons this might occur. Physiologically, exercise can prompt the release of hormones that stimulate hunger, causing people to eat more. Additionally, as the article discusses, some dieters often reward themselves after workouts by consuming high-calorie foods that merely replace the calories burned during the workout.
Another possible explanation addressed in the article looks to social psychological research performed by Roy Baumeister and colleagues. In their pivotal studies about self-regulation, they found that when people are depleted of the energy to exercise self-control, they often engage in disinhibited behaviors, such as eating more. These studies have interesting implications for weight loss and exercise. For instance, people who are exercising frequently might also be dieting to lose weight. Dieters often employ substantial self-restraint throughout the day to resist tempting food. Thus, it might not be exercise that is leading to increased eating; rather, the frequent self-monitoring process of dieters may deplete them of the energy needed to resist fattening foods. On the other hand, exercise lowers blood sugar levels, including that of glucose, which has been intimately linked to self-regulatory abilities (Gailliot et al., 2007). Is it the case then that post-exercise hunger, which often leads to the consumption of high-sugar food, is simply the body’s way of returning to homeostasis?
It seems that social psychological research will have much more to say about this topic in the future, as it remains unclear whether it is dieting or exercise that is directly leading to the consumption of fattening foods. And if the booming weight-loss market tells us anything, it’s that people want to know the best way to get fit and look good.