A long walk – even early in the morning – can reduce levels of the food intake hormone that helps regulate appetite, a study by US researchers suggests.
The findings show that people can improve their dietary intake by performing regular physical activity despite a lack of extra weight, suggesting the aim is to increase gut health and reduce obesity in our relatively sedentary culture.
Previous research has found that prolonged exercise can stimulate the release of growth hormones, which stimulate the production of appetite-regulating molecules called peptides.
Those substances – hunger, satiety and satiety-regulating peptides – are believed to increase appetite but not excess appetite.
But the new study, published in the Journal of Physiology, suggests that exercise may induce a “temporary but dramatic change” in the levels of IGF-1 (insulin-like growth factor-1), which regulates the secretion of the peptides.
Findings show exercise may induce a ‘temporary but dramatic change’ in the levels of IGF-1. Photograph: Marcos Pereira/AP
Researchers studied 25 healthy elderly men in a treadmill test. They found the results varied considerably across the participants, but that the highest level of IGF-1 – 5.9% – was found when the participants exercised for up to 30 minutes at a moderate pace in the morning.
The study’s lead author, Reshma Jagsi, said the results of the experiment could lead to the development of innovative methods to encourage people to engage in physical activity despite lack of extra weight.
“Most people choose to exercise when they’re overweight and above an ideal weight, but many people fall short of meeting that target,” said Jagsi, from the University of Maryland, Baltimore County.
“Obesity is now the leading cause of adult deaths in the US, which is alarming given that we are living longer and healthier lives. Insulin levels are the principle players in obesity because they have a direct impact on how much weight people gain.
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“People who exercise may put extra weight on, but they may do so without feeling full. This study suggests that exercise is not simply an end in itself, but may potentially act as a mechanism to address obesity.”
In the UK, the average weight for a male aged 16-34 is 11st 6lb (88kg), while for females it is 14st 7lb (86kg). Two-thirds of adults are now classed as overweight or obese and the rise of fasting coffee cups is likely to accelerate the issue.
Elaine Frier, director of behavioural endocrinology at the National Institute of Health and Clinical Excellence, said: “The findings suggest that, particularly when training for long periods, people’s production of the appetite-regulating peptides may be increased. These results are interesting, but their real significance would only be assessed when studying long-term outcomes, including the levels of these peptides in the blood as seen in weight measurements.”