Intense physical exercises suppress appetite more effectively than light workouts.

The study examined the impact of exercise intensity on levels of the hormone ghrelin and appetite in both men and women. Ghrelin is known as the "hunger hormone" and is associated with the sensation of needing food.

“We found that high-intensity exercise suppresses ghrelin levels more significantly than moderate-intensity exercise,” says lead author Kara Anderson, PhD, a researcher at the University of Virginia in Charlottesville, Virginia. “Additionally, we discovered that individuals felt less hungry after high-intensity workouts compared to moderate-intensity ones.”

Ghrelin circulates in acylated (AG) and desacylated (DAG) forms, both of which are known to affect appetite. Data concerning the effects of exercise intensity on AG and DAG levels and their influence on appetite are limited and primarily focus on men, the study notes.

To address this gap, the study involved eight men and six women. Participants fasted overnight and then performed exercises of varying intensity (determined by blood lactate levels), after which they self-evaluated their appetite.

Women had higher baseline ghrelin levels compared to men, the study highlights. However, according to the findings, only women showed a “significant decrease in AG” after intense exercise.

“We found that moderate-intensity exercise either did not change ghrelin levels or led to an increase,” the study states. The data suggest that to induce suppression of ghrelin levels, exercise above the lactate threshold may be necessary.

Researchers also acknowledged the need for further work to determine how the effects of exercise may vary by sex.

It has been established that ghrelin has a wide range of biological effects in areas such as energy balance, appetite, glucose homeostasis, immune function, sleep, and memory.

Exercise should be viewed as a “medicine,” where the “dosage” should be tailored to an individual's personal goals,” Anderson states.

This research indicates that high-intensity exercises may be crucial for appetite suppression, which can be particularly beneficial in a weight loss program.