More than 40% of U.S. adults are living with obesity, and millions more are trying to lose weight each year.
In fact, surveys show nearly half of Americans say they’re actively trying to lose weight. And for many, that means hitting the gym hard with the hope of burning more calories.
But new research suggests that might not work the way we think.
You hit the gym, you sweat, you hope the calories burn. That’s because most people often overestimate calories burned during exercise and underestimate what they eat.
But if you’re putting in the work and not seeing the results, there may be a scientific reason for that.
“Your body works to try to keep the total calories burned every day within a pretty narrow range,” said Herman Pontzer, an evolutionary anthropologist at Duke University School of Medicine.
Duke researchers tested that idea, studying a hunter-gatherer tribe in Tanzania, where the women walk about 7 miles each and every day and the men 9 miles.
“They get more activity in a day than most Americans get in a week,” said Pontzer.
But despite all that movement …
“You can be as active as a hunter-gatherer, and you’re still burning as many calories every day as a more sedentary American,” explained Pontzer.
Why? Because your body adapts. When you move more, it may conserve energy somewhere else, cutting back on things like stress responses or inflammation.
“When it comes to weight loss, you wanna focus on your diet,” said Pontzer.
So, experts say, don’t think of exercise as your main weight-loss tool. Instead, focus on what you’re eating, find a diet that keeps you full, and habits you can actually stick with.
And when it comes to working out …
“The right exercise to do is the one you’ll stick with,” said Pontzer.
Because in the end, exercise builds a healthier body, but your diet drives the number on the scale.
New weight loss drugs, like Ozempic and Wegovy, are also changing the conversation. Experts say they work not by boosting metabolism, but by helping people eat less without feeling hungry. Reinforcing what science has been showing, that when it comes to weight loss, diet plays the biggest role.