Hitting gym to lose weight? Science says exercise alone might not be enough. Here’s what you need to know

If you're hitting the gym thinking it's the ultimate solution for weight loss, it might be time to reconsider your approach. Calorie burn in active vs sedentary lifestyles When Herman Pontzer began researching the metabolism of the Hadza, a modern hunter-gatherer tribe in Tanzania, he expected their calorie burn to be through the roof. What is ‘constrained total energy expenditure mode’ "That was unexpected," said Pontzer, now an evolutionary anthropologist at Duke University and author of the 2021 book Burn, which explores the science of metabolism. The results were so surprising that they led him to create a new theory about how we burn calories, known as the “constrained total energy expenditure model.” Exercise alone may not be the most effective strategy for weight loss This theory suggests that our bodies and brains can adjust the number of calories we burn by slowing down or even shutting down certain biological functions when we're more active, ultimately keeping our total calorie burn within a narrow range. "We've studied people who are extremely active," including marathon runners crossing the U.S., Pontzer explained, "and those who are very sedentary, and it turns out they burn about the same number of calories."