Bad news for those of you who are still trying to work off those holiday pounds: No matter how much exercise you get, if that’s all you do, the needle on your scale is unlikely to move very much.
A new study has found that while exercise is good for you, it may not help you lose weight.
That finding by Herman Pontzer, an anthropologist at New York's Hunter College, stems from an earlier study that he and his colleagues conducted looking at a tribe in Tanzania.
“I did a project measuring energy expenditure in a traditional hunting and gathering population called the Hadza, who live in northern Tanzania. And they don’t have any farming and machines and anything like that. They are very active every day, walking a lot to hunt wild game and gather wild plant foods,” he said.
Pontzer figured members of the Hadza tribe would burn a lot of extra calories because of their extreme physical activity. But they didn’t.
Researchers then decided to compare the levels of energy expenditure among a group of Westerners who enjoy modern conveniences.
They looked at the number of calories burned by more than 300 Americans and Europeans who engaged in different levels of physical activity. They included very active people, those who were moderately active and couch potatoes that got little or no exercise.
Researchers determined their energy expenditures by measuring the amount of carbon dioxide each participant produced. The more activity, the higher the levels of CO2.
Body adapts to activity
Researchers found that the amount of exercise people did made little difference in the number of calories they burned.
“Your average energy expenditure levels, the calories you burn per day, is the same, whether you’re just moderately active or extremely physically active. We don’t see any increase in calories per day there because the body seems to be adapting to those higher levels of activity and trying to keep energy levels - calories per day - the same.”
Pontzer says researchers did find that moderately active people burned about 200 more calories a day than the couch potatoes.
But he is quick to add that just because it doesn't help you shed pounds, you should not give up your daily workout.
“You’re not off the hook there. So, exercise is really important for keeping your heart healthy and your lungs and your mind and for aging well. We have all sorts of really great benefits. But this says that... exercise maybe isn’t going to be the best tool for managing your weight and especially trying to lose weight.”
Pontzer says his findings, published in the journal Current Biology, are just more proof that being healthy is all about the right combination of a sensible diet with exercise.
It also might mean that there's not much benefit to be gained from overdoing it, and that moderate exercise is the way to go.