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TOPIC: Fitbit and MFP

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October 3, 2012 8:48 PM
I don't understand how the Fitbit and MFP work together. My fitbit says that I burned 2315 calories today. With a 500 calorie deficit, that means I should be able to eat 1815 (right?). But MFP has me at 1750 and my adjustment was for only 6. I realize the difference between 1756 & 1815 isn't vast - it's the idea that it tieing out. This is only a math problem so why am I having such a hard time???
October 3, 2012 9:29 PM
It confuses me too so what I now do is I look at my total calories burned on my fitbit the yesterday then I subtract todays food I am logging on MFP from that. I am close to goal so I subtract 10% from yesterday and eat that. You could just subtract your 500.

My diary is open if you want to check it out and feel free to PM me if you need to.
Edited by mockchoc On October 3, 2012 9:29 PM
October 6, 2012 3:00 PM

Sorry for any confusion. I have posted this before, so my apologies if you have seen it, but it is very useful for understanding how MyFitnessPal and Fitbit work. 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. The way our site accounts for this is to add JUST the difference in calories to your exercise diary as a "Fitbit Calorie Adjustment"

Because our site is counting down from a goal number to zero, and the 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.

If you look back through your exercise diary pages, you will likely see some days in which a Fitbit calorie adjustment has been added, and others when it has not. The days where the adjustment appears will be the days that you were more active than usual, apart from any exercise that you logged as such using the MFP site.

Please note that the Fitbit integration can only ADD calories to your daily need, so it may be necessary to lower your MFP profile's activity level one notch or more, to give the Fitbit "elbow room" to do its work.

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

If you want to verify that the Fitbit calorie adjustment is working correctly, here's an explanation of how we calculate the adjustment:

To understand your Fitbit Calorie Adjustment for any completed day, take your "Calories burned from normal daily activity" on your goals page (

Add to it any exercise calories you've burned as shown in your exercise diary, but don't include your Fitbit Adjustment

Compare that total to your calories burned on your Fitbit (only if it's an entire day's worth of calories)

The difference between the two is your Fitbit adjustment

At this time we do not allow negative Fitbit adjustments, so we bring your Fitbit adjustment back to 0 if it's negative. We are looking into allowing negative adjustments in the future, but for now, you might want to lower your MyFitnessPal "activity level" in your diet/fitness profile by a notch, if possible, if you're not seeing a regular "positive" adjustment.

The adjustment that you see during the course of an incomplete day is a projection made for the entire day, based on the amount of activity currently reported by Fitbit. Your adjustment will become more accurate of the course of the day, each time your Fitbit has a chance to update with your account on

Here is a more detailed explanation of the way we calculate the projected adjustment before a day is over:

If you only have a partial day's worth of calories on your Fitbit, we calculate how many minutes are left in the day, and we use that to create a projection for how many calories you'll burn today.

The calculation is: Fitbit calories so far for the day + (minutes left in the day / total minutes in a day) * (calories burned from normal daily activity)

So for example, if it's 12 noon, you've burned 1200 calories so far today according to Fitbit, and your calories burned from normal daily activity on MFP is 2000, the projection is:

1200 + (720 / 1440) * 2000 =
1200 + (1/2) * 2000 =
1200 + 1000=
so the adjustment becomes
2200 - 2000 (mfp calories burned from normal daily activity)=

Hope this helps.

MyFitnessPal Staff

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