Exercise Timing May Prevent Overeating
When you get home after a long day at work, your first impulse may be to start stuffing yourself with any food you can grab and then park yourself on a chair or sofa. This may be because you are truly hungry or it may be as a response to the challenging mental tasks you faced all day long. This new research published in Medicine & Science in Sports & Exercise suggests that if you go to work out or do some fitness activities after your workday, or after performing any in-depth mental tasks, you will likely consume fewer calories. Doing exercise after mentally taxing tasks seems to reduce caloric intake.
Other past studies have highlighted how draining mental tasks like a big exam, applying for a grant and rushing to meet a grant deadline, and other strenuous mental tasks really drain our brain’s energy stores, and seem to instigate increased food intake right after the mental effort. This new study wanted to explore whether “certain non-caloric actions” could restore individuals, helping them to feel refreshed and recharged.
The study recruited 38 undergraduate students to take and complete a graduate level exam. The subjects were then divided into two groups and following the exam, one group was given a 15 minute relaxation period, while the other group performed 15 minutes of high-intensity interval training on a treadmill. (As a baseline, all subjects were given a 35 minute rest period during the prior week to establish relaxed mode feelings). After the two groups exercised or relaxed, they were offered an all-you-can-eat lunch of pizza.
The group who took the exam and then rested ate 100 calories more than they had the previous week, after the 35 minute relaxation period. The exercise group ate 25 calories less than they had the week before, after the relaxation period. The researchers took note that the exercise group had higher lactate levels post-exercise, which may help to replenish the brain’s energy needs. Of course, there was no surprise that food containing glucose would also replenish the brain’s energy levels, explaining why one group ate more pizza calories than the prior week.
In addition to the lactate level impact on brain energy needs, the researchers also suggest that exercise directly impacts hunger and satiety hormone levels which may modulate caloric need after mentally-taxing efforts.
The study suggests how turning to exercise after a mentally taxing task or difficult work day or school day could help to offset caloric intake and reduce the risk of weight gain. Based on these findings and given the current rates of childhood obesity, it might be a good idea to let your kids play outdoors or indoors right after coming home from school, before they have the standard post-school snack, especially if they have weight issues.