Why does logging 20,000 steps on FitBit only show 82 additional calories burned?

Apologies for any confusion regarding your Fitbit calorie adjustment.

You burn a fair number of calories over the course of the day just by sustaining your normal bodily functions. Our estimate for how many calories you will burn is based on your weight, age, gender, and the activity level you report in your profile. From this, we subtract an amount of calories so that you will be at a deficit every day if you eat your calorie goal. Thus, you will lose weight because your body will need to burn some of its stored fat to make up the difference. We show this goal as your NetCalorie goal, and you are essentially counting down to zero from this goal, every time you log food that you've eaten.

If you log exercise, this represents EXTRA burned calories that our estimate of your normal activity has not accounted for. Because our goal is to keep you at a steady, healthy, sustainable amount of weight loss, you "earn back" these exercise calories as additional calories to eat. Exercising is like making a deposit in your calorie account. You make the withdrawal by eating. Because our initial calculation ALREADY puts you in a weight loss deficit, eating "back" the calories you exercised will not slow your weight loss, but it will nourish your body which is depleted after burning the extra calories. So, your calorie goal on our site starts at a number that counts down to zero as you eat, but exercise that you record pushes that number back up a bit, so that you don't undernourish your body.

The Fitbit site counts UP from zero, as it calculates how many calories you have burned over the course of a day. If, when our two sites compare their information, it seems that you are being more active on a given day than our general estimate takes into account, you "earn" those extra calories as well. Again, the goal here is to keep you at a healthy, steady calorie deficit. The relationship between our site and the Fitbit site takes into account any exercise you record. If, beyond our initial estimate of your calorie goal, and the exercise you log, the Fitbit shows that you are being more active than we expected, then you earn those extra calories back. If Fitbit reports that you are being less active than we expected, you will see a "negative" calorie adjustment that will lower your Net Calorie goal.

Because our site is counting down from a goal number to zero, and the fitbit.com site is counting UP from zero, you will never actually see, on our site, the number of calories that you see on the Fitbit site. What you will see is the anticipated DIFFERENCE between what you're burning in Fitbit's tracking of your movement, and what we expected you to burn based on our estimate, recorded as an exercise. The adjustment represents our projection of your calorie adjustment for the entire remainder of the day. As you are more or less active, the adjustment will become more precise. We base the projection on your activity level early in the day, and "assume" you will be "as active" the rest of the day. If this proves not to be the case based on later updates from the Fitbit device, we'll raise or lower your adjustment to fine tune it.

It is important to be sure that your profile information on our site and the fitbit.com site matches, in terms of your height, weight, age, gender, etc. so that the Fitbit is calculating your caloric burn as accurately as possible.

Details about the calculation of any adjustment can be viewed by clicking the small "i" next to the adjustment in your Exercise Diary (on the full website) or by tapping the adjustment itself in the Exercise Diary of the latest versions of the MyFitnessPal iPhone or Android app.

By default, MyFitnessPal will show you only positive calorie adjustments. To permit negative adjustments, log in to the full MyFitnessPal site at http://www.myfitnesspal.com and click "My Home" then "Settings" then "Diary Settings." Check the box for "Enable Negative Adjustments" then click "Save Changes"

If you are typically unable to sync your device until late in the day, you may wish to leave negative adjustments "off."