My students in Flexible Eating 101 ask me this question quite frequently during our check-in calls- “should I be eating back my exercise calories”?
Meaning… if I exercise on a Tuesday and burned 500 calories, should I be eating an extra 500 calories that day?
The quick answer: No.
Let me explain why.
If you are tracking exercise in a calorie tracking app such as MyFitnessPal, the app is giving you an estimation for the number of calories roughly burned.
For example, if I added in 30 minutes of walking in the MFP app and it calculated that I burned about 189 calories, how does the app know how fast I walked? I could have been walking slowly or fast- the app can’t account for this.
Most calorie trackers have a very small exercise database with limited ability for customization.
If I eat back 189 calories to account for the physical activity I burned, there’s the risk I burned less than what the app says, meaning I may not be in a calorie deficit anymore if I eat back my exercise calories.
In nutrition, we look at weekly averages for calories burned based on the duration of physical activity you are doing as well as the type of physical activity.
Because there’s no way to exactly know how many calories you burned from physical activity in a non-clinical setting, we estimate. And I always estimate calorie needs for my students to be on the lower side of their physical activity regimen to account for this. And we know in nutrition that estimating calories this way, works VERY well if the person calculating your nutrition needs is doing so the right way.
Now you might be thinking but wait, I have a Fitbit and Apple watch that tells me how many calories I’m burning!
I dug into the research to see how accurate these devices are and it seems that many devices are not estimating your calories burned accurately. There are a lot of discrepancies and therefore, many research studies question the use of these devices to estimate calories burned.
But then again, everything is an estimation- the way calories are calculated and how many calories are burned. So utilizing these devices to encourage you to do physical activity is a plus in my book.
Rather than focusing on the exact calories burned, focus on the amount of time you are completing a physical activity or the distance you are covering.
I have no idea how many calories I burn walking 3 miles daily but I know I complete about 3 miles since I carry my phone every time I complete steps throughout the day. And having this 3-mile daily goal pushes me to complete the 3 miles whether it takes me 45 minutes or 60 minutes depending on my pace.
It’s already a lot of effort to track calories & macros in food. You don’t NEED to add this whole layer of figuring out how many calories you burned during physical activity each day. You don’t need another thing to track in terms of a calorie perspective.
Cover the distance/time for your physical activity and track your weekly weight loss. You CAN be successful in losing weight without ever really knowing how many calories you specifically burned from physical activity.