In addition to its other potential health benefits, intermittent fasting may cause hormone changes that boost one’s motivation to exercise. The findings were detailed in a study recently published in the Journal of Endocrinology, where researchers explain that intermittent fasting — as well as general meal restriction — boosts the ‘hunger hormone’ ghrelin and its ability to boost exercise motivation.
Humans have two hormones that play important roles in appetite and satiation: ghrelin, the ‘hunger hormone,’ and leptin, the hormone that eliminates the appetite after eating. When someone goes a number of hours without eating, the amount of ghrelin in their blood increases; after eating, the levels of this hormone plummet.
According to the latest study, high levels of ghrelin may increase exercise motivation in addition to appetite — something that makes sense when you consider that acquiring food requires effort. Past research has found links between ghrelin and increased endurance during exercise; beyond that, many people have reported temporary surges in energy and trouble sleeping when fasting or following diet protocols that imitate fasting.
Researchers focused on mice with this study, finding that mice given limited access to food only twice a day displayed more voluntary time spent on the running wheel than mice given unlimited access to food. The increased activity was noted despite the fact that both groups of mice ultimately consumed around the same amount of calories.
Beyond that, the researchers also found that mice who had unlimited food access, but who were also given ghrelin, voluntarily increased their running levels ‘significantly.’ The findings suggest that people who struggle with exercise motivation may increase their desire to get active by intermittent fasting or otherwise limiting their food intake to a brief period of time twice a day.