- An hour of moderate-intensity exercise reduced sensations of hunger in people with overweight and obesity in a new study.
- The authors of the study attribute the reduction in hunger to an alteration in the levels of certain appetite-related peptides produced by muscles during exercise.
- Research suggests that the bodies of people with overweight or obesity react differently to the exertion of exercise, and that the suppression of hunger may be one of these unique effects.
- While not as drastic a reduction in hunger as experienced with GLP-1 medications, the study suggests that exercise offers people with overweight and obesity an extra hand when it comes to appetite control.
Moderate-intensity exercise appears to have resulted in a reduction of appetite in people with overweight and obesity in a new study conducted by researchers from Iran and Australia.
While this may disappoint those who hope they can eat more because they exercise, the good news is that the reduction in hunger may make achieving weight-loss goals a bit easier.
The study — which appears in the journal
The appetite inhibitors that increased in levels were the cytokine protein interleukin 6 (IL-6) and the hormone-like protein irisin, while levels of the hormone neuropeptide Y (NPY), the stimulant, fell.
The researchers also tracked the responses to exercise of interleukin 7 (IL-7) and leptin, but saw no notable changes in their levels due to exercise.
Study participants were also questioned by the researchers, and reported reduced sensations of hunger after exercise.
The study, conducted in Iran, involved eleven males with obesity who were metabolically healthy, non-smokers, taking no medication, and living inactive lifestyles as defined by the International Physical Activity Questionnaire.
All participated in two randomized crossover trials separated by at least seven days. The four-hour trials — which included meals and measurement-taking — were identical except that one included a 60-minute bicycling exercise period and the other a rest period instead. This exercise-less trial was used as a control.
According to the authors of the study, until recently, much appetite research has focused on hormonal influences. This has now changed, with a greater appreciation of myokines, cytokines, adipokines, and in particular, peptides as potentially important factors in appetite.
This is underscored by the popularity of GLP-1 drugs such as Wegovy and Ozempic, which mimic the glucagon-like peptide-1 hormone, which helps control hunger.
Mir Ali, MD, a board-certified general surgeon, bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA, who was not involved in this study, told Medical News Today he was “not surprised by the findings from this study“ because “there are complex interactions of many hormones to induce hunger or satiety.”
“Though this study was a small sample,” Ali noted, “it does show that we do not have a full understanding of this aspect of obesity.”
Kara C. Anderson, MD, a postdoctoral fellow at the University of Virginia School of Medicine, also not involved in this research, explained what recent research has suggested about the peptides investigated in the new study:
“Previous data has shown that the hormone NPY, and signaling proteins IL-6 and irisin, may be involved with energy balance and metabolism. Increased levels of NPY have been associated with appetite stimulation (increased hunger). IL-6 and irisin are mainly released from skeletal muscle and play a role in metabolism as well, with studies showing increased levels of IL-6 are associated with appetite suppression (decreased hunger). Importantly, all may interact with other energy regulating hormones such as ghrelin, GLP-1, and PYY.”
In turn, Ali pointed out that “the appetite suppressive effect reported in this study seems to be much less than what patients report with GLP-1 medications.”
“Some data,” Anderson noted, “has shown that post-exercise appetite suppression may be blunted in individuals with obesity, while others have shown similar responses between those who are obese and lean.”
Nonetheless, it is a complicated situation, she said. “Due to the wide variability in protocols — meal status (whether they are fasted or ate food beforehand), exercise mode, duration, and intensity — it is difficult to form a consensus.”
The authors of the study suggest that exercise may be viewed as yet another means of appetite-control for people with overweight or obesity. It is, of course, a Healthful idea in any event.
“Unfortunately,” opined Ali, “most of my patients do not report feeling less hungry after exercise, and indeed feel they can eat more because they have exercised.”
“Although there are many factors that are involved in whether an individual is hungry or not,” said Anderson, “exercise may be a tool to acutely suppress appetite and may aid in weight loss/management programs.”
“One thing that people may take away from this study is that people should try to listen to the signals the body is sending them,” Ali emphasized.
“If after exercise, they feel less hungry, then they should try to eat less. In my experience, people tend to ignore these types of subtle signals,” he reported.
