Eating less often makes it easier to exercise more
If you limit the number of hours you can eat per day, your motivation to exercise increases. Or, if you prefer to put it the other way around, your aversion to physical activity decreases. This is suggested by a Japanese animal study recently published in the Journal of Endocrinology. The hunger hormone ghrelin, which is released when your stomach is empty, makes physical movement easier, according to the Japanese.Study
The researchers put mice in a cage with a treadmill, and then monitored how many minutes a day the animals ran on the device, without being forced to do so. Due to a genetic intervention, some of the mice were unable to produce ghrelin.


Both regular mice [WT-Ex] and mice that were unable to produce ghrelin [GKO-Ex] ran more and more often in their treadmill if they could only eat a few hours a day [RF] than if they had unlimited access to feed [Ad -Lib]. However, the WT mice moved more than the GKO mice.

When the researchers gave the GKO mice GHRP-6, the animals started to run considerably more. GHRP-6 is a ghrelin agonist. GHRP-6 a peptide significantly smaller than ghrelin, yet able to activate the receptor for ghrelin.

Above you may see how ghrelin stimulates mice to exercise physically. When normal mice can no longer eat unlimited food, the concentration of dopamine in the nucleus accumbens in their brains increases. The same is the case in the mice that cannot produce ghrelin, and receive the gehrelin agonist GHRP-6.
The nucleus accumbens plays a key role in positive experiences such as desire, motivation, passion and satisfaction.
"Our findings suggest that hunger, which promotes ghrelin production, may also be involved in increasing motivation for voluntary exercise, when feeding is limited", zegt co-auteur Yuji Tajiri in een persbericht. [ October 19, 2019] "Therefore, maintaining a healthy eating routine, with regular mealtimes or fasting, could also encourage motivation for exercise in overweight people."

"These findings and previous reports are based on animal studies, so much more work is needed to confirm that this ghrelin response is also present in people. If it can be established in clinical practice, it not only opens up new cost-effective diet and exercise strategies but may also indicate a new therapeutic application for ghrelin-mimicking drugs."
J Endocrinol. 2020;244(1):123-32.