Jan 14, 2026 12:53 AM
(This post was last modified: Jan 14, 2026 01:02 AM by C C.)
https://www.sciencefocus.com/the-human-b...s-theories
EXCERPT: A growing body of evidence suggests that exercise, on its own, has far less of an impact on your weight than you might think. In fact, scientific studies have even shown that people exercising five days a week with no change in diet may lose only a few kilos a year, and many – particularly women – will lose none at all.
Even more mysteriously, studies have shown that highly active people, and even ultra-endurance athletes, simply do not burn as much energy as would be expected given their levels of physical activity.
Why? The theory is that their bodies seem to adapt to high levels of exercise, limiting their total daily energy use to prevent them losing weight.
Exercise is, of course, crucially important to our overall health. It has positive effects on everything from our bone density to our mental wellbeing. It can reduce the likelihood of a range of health problems including diabetes, heart disease, cancer and dementia.
But when it comes to shrinking belly fat, some data suggests creating an energy deficit through diet is far more effective than exercise.
So, what’s really going on here? Are all those freezing park runs, punishing functional fitness classes and expensive exercise machines helping us lose weight or not? Here’s the surprising science of how exercise really changes your body.
[...] Pontzer explained his surprising results through what has become known as the ‘constrained energy expenditure hypothesis.’ The theory suggests that humans, and indeed many other animals, may have a built-in system to keep our overall energy expenditure within a fixed range, no matter how much physical activity we do. In other words, Pontzer suggests your body generally has a set amount of energy to use each day... (MORE - missing details)
EXCERPT: A growing body of evidence suggests that exercise, on its own, has far less of an impact on your weight than you might think. In fact, scientific studies have even shown that people exercising five days a week with no change in diet may lose only a few kilos a year, and many – particularly women – will lose none at all.
Even more mysteriously, studies have shown that highly active people, and even ultra-endurance athletes, simply do not burn as much energy as would be expected given their levels of physical activity.
Why? The theory is that their bodies seem to adapt to high levels of exercise, limiting their total daily energy use to prevent them losing weight.
Exercise is, of course, crucially important to our overall health. It has positive effects on everything from our bone density to our mental wellbeing. It can reduce the likelihood of a range of health problems including diabetes, heart disease, cancer and dementia.
But when it comes to shrinking belly fat, some data suggests creating an energy deficit through diet is far more effective than exercise.
So, what’s really going on here? Are all those freezing park runs, punishing functional fitness classes and expensive exercise machines helping us lose weight or not? Here’s the surprising science of how exercise really changes your body.
[...] Pontzer explained his surprising results through what has become known as the ‘constrained energy expenditure hypothesis.’ The theory suggests that humans, and indeed many other animals, may have a built-in system to keep our overall energy expenditure within a fixed range, no matter how much physical activity we do. In other words, Pontzer suggests your body generally has a set amount of energy to use each day... (MORE - missing details)
