More Activity Doesn’t Burn More Calories: New Study

Get your steps in.

Go on a jog.

Sit less.

Move more.

The assumption has always been simple: the more physical activity we do, the more calories we burn.

But a new study from researchers at Duke University, recently published in the journal Current Biology, provides powerful evidence that increasing physical activity does not necessarily lead to more calorie expenditure.

The Idea of “Constrained Energy Expenditure”

The paper introduces the concept of constrained total energy expenditure.

Here is how it works.

If we go for a walk, a run, or a bike ride, our calorie expenditure increases. That part isn’t surprising. But after the exercise ends, our physiology automatically finds ways to conserve energy throughout the rest of the day.

The end result is that being more active doesn’t necessarily mean we burn more calories by the end of the day.

For example:

• We burn 500 calories during a workout.

• Our body conserves about 500 calories during the rest of the day.

This compensation appears to happen automatically.

Key Takeaways From the Study

Researchers highlighted several important findings:

• Humans and other mammals compensate for increased physical activity. After we burn calories through activity, our bodies naturally reduce energy expenditure elsewhere. This is known as energy compensation.

• Energy compensation is most pronounced with aerobic exercise. The effect is even stronger when aerobic exercise is combined with calorie restriction.

• One place the body compensates is basal metabolic rate. When we are at rest, we may burn even fewer calories than we normally would.

A Different Effect With Strength Training

Interestingly, the researchers noted that this energy compensation did not occur after resistance training. In fact, they observed the opposite effect.

After strength training, people appeared to burn more calories during the rest of the day.

Why This Matters

The authors conclude that this idea of constrained energy expenditure may explain why most people don’t lose weight from cardio or increased physical activity alone—both in research studies and in the real world.

Final Thought

This study doesn’t suggest we shouldn’t be active or perform cardio. Physical activity is still incredibly beneficial for our health.

But it does reinforce an important point: exercise doesn’t always lead to the calorie burn we expect.

Cardio and physical activity are good for us—but they may not do what we often assume they can do when it comes to weight loss.