Researchers did not measure the exact type of exercise participants engaged in, but rather had them use a wearable fitness tracker that measures acceleration, and the intensity of that acceleration, which was coded as “light” or “moderate-to-vigorous”mphysical activity. In the original intervention, researchers often recommended brisk walking as a way to achieve moderate-to-vigorous physical activity. Dietary lapse was defined as eating or drinking likely to cause weight gain or prevent weight loss, specifically eating a larger portion than intended, eating at a time when one had not intended to eat, or eating an energy-dense food one had intended to avoid. Throughout the day, the researchers sent brief surveys to participants’ smartphones. One of the survey questions asked, “Since the last time you completed this survey, did you have a dietary lapse?”
Because lapses were self-reported, Crochiere said it remains unknown whether calories were actually decreased or increased following exercise, and this should be investigated further. Although the researchers did not investigate why physical activity seems to protect against overeating, Crochiere said other evidence suggests hormones released following exercise may reduce hunger and food intake. “Another potential explanation is that exercise boosts mood or self-esteem,” she said, “which then improves motivation to eat well or within one’s diet. It also may temporarily increase commitment to dietary goals because individuals do not want to undo the hard work they put into physical activity.”
Since most behavioral weight loss programs prescribe exercise for its health benefits and because it burns calories, these findings suggest that exercise may also aid in adhering to a reduced-calorie diet, perhaps through improved regulation of eating behavior.
“One more reason to recommend exercise if you are a physician,” Crochiere said, “and one more reason to engage in exercise if you are a patient seeking weight loss.”