I don't understand MFP's numbers

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Madison_LH
Madison_LH Posts: 28 Member
in Health and Weight Loss
I'm confused about the numbers I've been getting on MFP. I've calculated my BMR, and it's 1290. I have MFP set to sedentary while pulling info from my Fitbit to track my daily exercise. Today it says I've burned 409 extra calories from the activity Fitbit has recorded. This should mean that today I've burned my BMR plus any activity, or 1290 + 409, which is 1699 calories (we'll call it 1700).

I also have my fitbit set to lose 1 lb/week, which should mean that, with a 500 calorie deficit, I should have eaten 1200 calories today COUNTING the extra calories from activity. However, I've consumed 1472 calories and MFP is telling me that I still have 137 calories remaining for today.

What gives? I feel like I'm missing something here.

Replies

  • aimeerhiannon
    aimeerhiannon Posts: 21 Member
    edited December 2015
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    I just had a look at your diary and I can see what you're saying. MFP will only let you set a specific net calorie goal - so you have yours set to 1200 calories. When you enter your exercise of 400 calories in it adds up the total (your calorie goal + the exercise calories) and lets you know how much you can eat and still be hitting the net calorie total of 1200. What you'll need to do if you want to eat a 500 calorie deficit every day is set your net calorie goal to 1290 (your BMR), enter the info from Fitbit into MFP and make sure you have a 500 calorie deficit each day yourself (i.e. make sure it has a green 500 at the end of the day). It would probably be best to do this retrospectively i.e. if today you used 1700 calories, tomorrow you would eat 1200, if tomorrow you used 1650, the following day you'd eat 1150, etc etc

    ETA: not sure if you already know this, but no matter how much you tell MFP you want to lose it will never drop your net calories below 1200 daily as it's a safe minimum to consume. So if when you signed up you told 1lb a week it will override that to give you the 1200 anyway
  • Abby2205
    Abby2205 Posts: 253 Member
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    What you are missing are the calories you burned in addition to BMR and exercise, through your everyday activity. Even a sedentary person burns more than their BMR every day.
  • Madison_LH
    Madison_LH Posts: 28 Member
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    The fitbit numbers aren't just exercise though. That includes all of my daily activity.
  • Abby2205
    Abby2205 Posts: 253 Member
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    Going from your diary, it looks like your base calorie goal was 1200 calories. I assume you also have MFP set for a 500 calorie deficit, so MFP has calculated that your daily calorie burn at sedentary is 1700 calories (I'm going to assume for this purpose that you aren't running into the MFP 1200 calories minimum that Aimee has described). How many calories does Fitbit say you have burned today? It looks like it has sent 2109 to MFP. Since MFP did its calculations assuming you would burn 1700, the Fitbit adjustment gives you 409 extra calories, resulting in a new calorie goal of 1609 to maintain a 500 calorie deficit.
    To test it out, try changing your goal in MFP to maintain your current weight. How many calories does it say you need to maintain?
  • youdontknowwhatyousaw
    youdontknowwhatyousaw Posts: 221 Member
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    Abby2205 has it correct. Because even at sedentary, you burn more than 1290. If you were in a coma, you'd burn 1290 calories a day. You were leading a lightly active lifestyle today, thusly you get more calories. Go to the Fitbit app and see what it says for calories in / calories out.
  • Madison_LH
    Madison_LH Posts: 28 Member
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    Fitbit says I've burned 1658 calories so far today. It's always under what MFP gives me.
  • Abby2205
    Abby2205 Posts: 253 Member
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    It sounds odd that 1658 Fitbit calories burned would cause MFP to give you 409 extra exercise calories. Now I see what you were saying about the 1290--not BMR, but what MFP apparently thinks is your maintenance, therefore when Fitbit pushes over 1600+ total activity calories burned, MFP gives you an adjustment. But 1290 is a very low number even for a sedentary person. What is your current weight and height?
  • jkal1979
    jkal1979 Posts: 1,896 Member
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    Abby2205 wrote: »
    It sounds odd that 1658 Fitbit calories burned would cause MFP to give you 409 extra exercise calories. Now I see what you were saying about the 1290--not BMR, but what MFP apparently thinks is your maintenance, therefore when Fitbit pushes over 1600+ total activity calories burned, MFP gives you an adjustment. But 1290 is a very low number even for a sedentary person. What is your current weight and height?

    It also depends on what time it was that she was looking at her Fitbit calorie burn. It gives a exercise burn estimate based off of what she may burn up until midnight.
  • avskk
    avskk Posts: 1,789 Member
    edited December 2015
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    A Fitbit doesn't measure "all" activity. It measures step-based activity. What you're missing is all the other activity inherent in even a sedentary lifestyle -- moving your arms, picking things up, brushing your hair, putting on clothes, going to the bathroom, typing this post, using your brain (the brain is one of the top calorie-burners in our bodies), eating and drinking, autonomic processes like respiration and digestion, bending or squatting to pet an animal, absentmindedly stretching halfway through the workday, and hundreds of other tiny activities we all perform without thinking of them. Your BMR is what your body would burn were you 100% immobile and on a respirator; your Fitbit calories are what you burned specifically while walking or running (plus your BMR); the difference is what you burn going about daily life.
  • Madison_LH
    Madison_LH Posts: 28 Member
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    I'm currently 5'2" and 125 lbs, which is heavy for me. I know that as a small woman my BMR is lower than the average.
  • Abby2205
    Abby2205 Posts: 253 Member
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    HI Madison! When I plug your stats into MFP I get that your maintenance calories should be 1710. So if your Fitbit is saying you are burning roughly 1700 calories a day, then you shouldn't be getting the ~400 extra calories from Fitbit adjustment (I know you already know that something is off, hence your original question). So my suggestion is check that you have correctly entered your current stats in both MFP and Fitbit. Also check that both are set to the same time zone.

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