Intermittent fasting has emerged as one of the most popular diet trends of recent years, credited not only with beneficial effects for body composition but health and lifestyle, too.
But intermittent fasting remains an area of research and scientists are uncovering new information about the effects of limiting food to dedicated mealtimes all the time. One of the latest is its effects on motivation to exercise.
The new experiment, which was published in the Journal of Endocrinology, focusses on the appetite-promoting hormone, ghrelin. Commonly referred to as the “hunger hormone”, previous studies have suggested a relationship between ghrelin and exercise (it is reported to be essential for endurance by increasing metabolism to meet the energy demands of prolonged workouts), but it has never been confirmed to have a direct effect on our motivation to exercise.
Conducted at Kurume University School of Medicine in Japan, researchers compared food intake and wheel-running activity between mice given unrestricted access to food and mice who were fed twice a day within a limited timeframe.
Both groups of mice consumed a similar amount of food, but the restricted mice ran significantly more. The same test on mice that were genetically altered to not have ghrelin on a restricted diet found them to run less than those with free access, but the effects were reversed once ghrelin was administered. Mice given ghrelin and free access to food also ran significantly more.
Of course, there’s only so much we can take from an animal study, and we don’t know for certain that the same ghrelin response is present in people. That said, the findings do suggest a link between hunger – which promotes ghrelin production – and increased motivation for voluntary exercise when limiting meal times.
Maintaining a healthy eating routine with regular mealtimes or fasting could, according to study author Dr Yuji Tajiri, also encourage motivation for exercise in overweight people. Yet another potential string in intermittent fasting’s bow, then.
Want to learn more about intermittent fasting? Form’s head of nutrition, Dr Adam Collins PhD, has put together an email short course on the subject, with an instalment sent to your inbox every day for six days. Sign up here.