Calories burned and Fitbit

ColoJessie · January 2017

For those of you who have their Fitbit synced to MFP, do you eat back all your calories burned, a portion or none. I have MFP set on sedentary so it seems that it starts giving me calories back after I hit a certain number of steps? Up until now I have just been manually logging my cardio using the app parameters and didn't have a rule about it but tended to only eat some back since I didn't know how accurate the calculations were.

So tell me, what has your experience with this been? Thanks in advance!

ssajwa1 · January 2017

I hope you get an answer because I'm wondering the same thing. It depends on the day, but sometimes I do eat back some of the calories. It makes me feel better that I'm always under my calorie goal -- but not necessarily under the base calorie goal.

macgurlnet · January 2017

It'll depend on how accurate your Fitbit is.

Some people (like me) find the Fitbit calorie burn estimate to be really accurate. I've been eating back all of my exercise calories since I first gone one 2 years ago, and have lost and maintained weight as expected.

It also depends on what you do for exercise. Fitbits are mostly step trackers, so things like walking & running will be more accurately estimated than other activities, like biking or swimming.

MFP is set up to give you a calorie goal WITHOUT exercise factored in. If you have a Fitbit synced and get additional calories, you should be able to eat them all.

Decide if you want to eat back 100% or 50% of the calories and do that for 4-6 weeks, then evaluate your weight loss over that time. You can increase or decrease the amount you're eating back at that point.

~Lyssa

SCoil123 · January 2017

I eat them. I've found it to be pretty accurate. I log my workouts on fitbit too so no activity gets entered onto MFP.

karahm78 · January 2017

I find my Fitbit burn to be extremely accurate so I am comfortable eating them.... However I usually try to eat half of them though to give done cushion/bonus burn while still enjoying some extra calories for the activity

PAV8888 · January 2017

MFP compares your estimated TDEE based on your activity level and exercise logged and compares it to what Fitbit came up with.

The positive or negative "exercise" adjustment is not a true "exercise" adjustment. It is just an accounting adjustment to equalize MFP's TDEE to the one estimated by Fitbit.

Over two years of pretty accurate MFP logging, almost daily weight ins adjusted via a trending weight app, a few DXA body composition scans, and spreadsheet comparisons of expected vs actual results I've concluded that in general Fitbit's TDEE estimation is pretty darn good especially if you engage in step based activities and your total exercise time is in the 1-2 hour a day range.

For me, Fitbit tends to be slightly over-optimistic when it comes to "vigorous activity" burns, and slightly pessimistic when it comes to activities of daily living. However over the course of a complete day it ends up being pretty darn accurate.

Based on the quality of my MFP logging which includes ZERO missed and less than 5 "I give up and I'm just going to guess" days since I started (as well as weighing food and liquids in grams and double checking the entries I use), the divergence between real and expected results indicates a TDEE over-estimation of between 0% and 7%, progressively increasing over time as I've varied my activities and become less concerned about the absolute accuracy of my food logs.

In brief... I suggest you eat at least 95% of your adjustment and after 4-6 weeks look at your progress and re-assess.

I would also suggest a deficit of no more than 20% of your TDEE (25% while obese) and eating the most you can while meeting your weight loss goals... but that's another story.

Maxematics · January 2017

When I first started losing weight I didn't eat back my exercise calories at all. It was a huge mistake and when I started feeling hungry from overtraining and undereating, I'd eat no more than 50%. After I went from 139 to 120 pounds losing 2.2 pounds per week, my body got hungrier and I had to eat more back. I'm so lucky I didn't sacrifice my body composition due to that. That was a year and a half ago. Now I happily eat back all of them most of the time and I'm 113 pounds. If I'm under my calorie goal too often, I lose more weight than Fitbit assumes. I was 107 in the summer and purposely gained some weight to build muscle. My surpluses via Fitbit seemed to be spot on.

SusanMFindlay · January 2017

I eat back my FitBit adjustment calories. Before I got the FitBit and just picked what looked like an appropriate activity level, I lost weight a lot faster than I was expecting to (and faster than is a good idea) following MFP's recommendation. The vast majority of my "extra" calories come from being on my feet all day; I only "work out" for a couple of hours a week. I do not log my workouts on MFP, but FitBit does tend to credit me with more calories for them than if I was just walking. (I have a Charge 2 which includes a heartrate monitor.)

My experience has been that, if my logging of food is accurate (and I think it is), FitBit does a very good job of estimating my daily calorie burn.

ssajwa1 · January 2017

Thanks, this was helpful.

Bearbo27 · January 2017

I always eat most if not all of my Fitbit calories back and have lost just fine and according to plan (currently am set for 1.5 lbs a week).

Calories burned and Fitbit

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