Should I eat back my exercise calories?

By Marisa Pruitt, RD, CD

Before you eat back your exercise calories, consider the three downsides of tracking exercise in your calorie tracking app.

1. Most calorie trackers have a very small exercise database with broad categories and limited customization. For example, you can pick "walking" for "30 minutes" and you might be able to estimate a mph or a minute-mile, but not always. Broad categories like this don't take into full account the extent to which you exerted effort and make it very difficult to accurately estimate the calories burned.
2. The estimated calories burned tend to be high. Meaning, you likely burn fewer calories doing the activity than what your app says. When you subtract those inaccurate calorie estimates from your daily calorie allotment, you will end up consuming more calories back than what was burned. This often results in a double whammy – you're not burning as many calories as the app says and you're eating back more calories than you may have burned.
3. Subtracting exercise calories from total calories consumed gives the impression that you can eat more. Most adults do not need to eat back their exercise calories because they are doing moderate activities, like walking, biking, swimming, weight-lifting, etc. These activities do not burn enough calories to require a post-workout snack, particularly if weight-loss is the intended goal. The exception to this rule is for athletes who do vigorous workouts for several hours each day. They, of course, require additional calories.

So...our recommendation is to track your exercise in some other way to avoid subtracting exercise calories from overall calories consumed. When it comes to weight loss, it is estimated that exercise plays, at best, a 30% role. The biggest factor in success is changing what you eat and how much. Eating back exercise calories results in a surplus which could potentially keep you from losing weight if that is your goal.