Does this FitBit calculation make sense?

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I just posted this on another thread, but it will likely get buried.

Are the MFP calorie and Fitbit calories supposed to be roughly the same?

For instance, I have 60lbs to lose, female, 5'6", 35 years old and my MFP profile set to Sedentary so FitBit can do its thing. That gives me 1,200 calories.

Yesterday, I actually ate 1,610 calories. My Fitbit Adjustment was 529 calories, so my total was 1,729 calories 'available' and MFP tells that I was 119 calories under for the day.

However, FitBit tells me that I only burned 2,461 calories yesterday, so I was actually 149 calories over my 1,000 calorie deficit.

So, the difference between MFP's recommendation and Fitbit's recommendation is over 250 calories different. I typically trust the Fitbit recommendation more, but would appreciate some input?

Replies

  • jemhh
    jemhh Posts: 14,261 Member
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    My suggestion is to follow your Fitbit's recommendation for 4 weeks and then decide whether it is accurate enough for you. You can adjust up/down from there by keeping in mind if it overstates your calories by 100 on an average day or 10% or whatever works for you.
  • shadow2soul
    shadow2soul Posts: 7,692 Member
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    Did you choose 2 lbs per week loss by chance?
    If so and providing my math is correct, you only have a 732 calorie deficit on MFP. MFP bottoms out at 1200, so if the deficit you selected would require eating below 1200 at your activity level selection then MFP won't give you the full deficit. Fitbit has no limitations in place. So your deficit on Fitbit is larger by about 268 calories than MFP.
  • smiles4jo
    smiles4jo Posts: 202 Member
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    Did you choose 2 lbs per week loss by chance?
    If so and providing my math is correct, you only have a 732 calorie deficit on MFP. MFP bottoms out at 1200, so if the deficit you selected would require eating below 1200 at your activity level selection then MFP won't give you the full deficit. Fitbit has no limitations in place. So your deficit on Fitbit is larger by about 268 calories than MFP.

    You're right I did and I knew it bottomed out at 1,200. I just assumed that once you got more calories, it would re-adjust to actually allow you to lose 2 lbs/week, instead of the 1.7 (or whatever it is) that you would be losing if you exclusively ate at 1,200 without any exercise calories.

    Thank you! Mystery solved!