There’s no doubt working out burns calories, but new research suggests that the gains may be less than previously thought. Thanks to ancient physiological adaptations, our bodies compensate for the calorie expenditure to preserve energy. For our early ancestors, this helped minimize food energy demands and reduced the time needed for foraging, but today, it may simply mean our workouts aren’t always producing the results shown on our Fitbits.

Calorie Compensation

For every 100 calories burned, the average person actually nets fewer than 72 calories cut, according to a revealing new study of how physical activity affects our metabolism.1 According to the study, in addition to physiological instincts, our bodies further undermine efforts to lose weight based on body composition and ratio of body fat to non-fat tissue. This means carrying extra pounds compounds calorie compensation and makes weight loss through exercise even more difficult for those who are already overweight. In some cases, these individuals lose up to 50 percent fewer calories. The researchers are not certain of the cause and effect — either people gain fat because their bodies are better energy compensators or their bodies become better energy compensators because they have more body fat.

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Before you get too discouraged, it’s important to remember that even if your body is compensating for 25 to 50 percent of the calories you’re expending during exercise, it’s still better than inactivity. In addition, the study did not consider food intake, which is an important part of any weight loss goal.

Maximize Calorie Burning with Strength Training and HIIT

To maximize the calorie burning aspect your workouts, experts suggest focusing on strength-training exercises using big muscle groups. Muscle burns more calories at rest than fat, so by building muscle mass, you will burn additional calories even when you are away from the gym. High-intensity interval training (HIIT) workouts are also efficient calorie burners. The afterburn effect, or post-exercise oxygen consumption (EPOC) causes the body to continue burning calories after high-intensity training, as the body strives to return to its baseline.

While the news may be discouraging for those counting calories, it’s important to remember the many benefits of exercise beyond calorie burning. Physical activity reduces cardiovascular mortality and morbidity, boosts mood, improves sleep, and raises energy levels. So, while your workouts may burn fewer calories than expected, maintaining workout schedules and remaining active continues to result in long-term rewards for both your mind and your body.

Authored by Zach Meeker, Research Assistant for Midwest Orthopaedics at Rush University Medical Center


1Vincent Careau, Lewis G. Halsey, Herman Pontzer, et. al. (2021). Energy compensation and adiposity in humans, Current Biology, ISSN 0960-9822.

2 Wilmore, J.J. Alterations in strength, body composition and anthropometric measurements consequent to a 10-week weight training program. Medicine & Science in Sports & Exercise

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