How do I do the maths?

hartk001
hartk001 Posts: 51 Member
edited November 21 in Health and Weight Loss
I'm just starting so let's see if I've got this right.

I'm aiming for 1450 calories a day. Fitbit shows me that I've burned 2933 calories. My food dairy from MyFitnessPal shows that I've eaten 1277 calories. It's probably a bit higher. How do I calculate the calories lost: 1450-(1277+2933) = 2760 or is it 1450-1277=173+2933 = 3106

Does that mean that, theoretically speaking, that if I'm down 3000 calories I should have lost about a pound? I do appreciate this is just one day, it's more to get an understanding as to how the maths work.

Replies

  • aeloine
    aeloine Posts: 2,163 Member
    edited August 2017
    It depends on what you're trying to calculate.

    1277-2933 is what your math should be, for the most part. 1,656 is your current deficit.

    Fitbit isn't always accurate. It's more of an estimate.


    Edited to add:
    It really is as simple as calories in vs. calories out.
  • MegaMooseEsq
    MegaMooseEsq Posts: 3,118 Member
    I'm a little confused by your question: 1450 is presumably the number of calories MFP wants you to eat in a day net, correct? That number already includes a deficit that depends on the numbers you gave MFP when you set up your account - current weight, normal daily activity mode, how much you want to lose a week. So if you set it to lose 1 lb a week, you should eat 1450 every day, plus eating back the calories you burned by exercise.

    As for the fitbit numbers, that 2933 number includes the calories you've burned by being alive, plus any calories on top of that from extra steps and deliberate exercise. You'll need to link the programs so it can figure out how many extra calories you should eat (or how much extra deficit you're getting), but it's not anywhere close the numbers you're thinking. For me, I burn about 2400 on the average day, so if I burned 2933 that's an extra 533 burned. If I was eating 1450/day (which remember includes a deficit), I would absolutely want to eat some or all of that 533 calories to compensate, otherwise my deficit would be too large, which can lead to exhaustion, nutritional issues, and/or hanger.

    Does that help at all? I know it's a lot to take in. Honestly, I just take fitbit's "active minutes" and put those into MFP's exercise diary to figure out where I'm at. Hopefully while I was typing someone else came up with a better answer.
  • fjmartini
    fjmartini Posts: 1,149 Member
    I used the Nike fitness trainer band when it first came out and the calorie usage was extremely over exaggerated. Unless you're burning calories from actually exercising, don't subtract the calories from your daily diary.
  • DX2JX2
    DX2JX2 Posts: 1,921 Member
    hartk001 wrote: »
    I'm just starting so let's see if I've got this right.

    I'm aiming for 1450 calories a day. Fitbit shows me that I've burned 2933 calories. My food dairy from MyFitnessPal shows that I've eaten 1277 calories. It's probably a bit higher. How do I calculate the calories lost: 1450-(1277+2933) = 2760 or is it 1450-1277=173+2933 = 3106

    Does that mean that, theoretically speaking, that if I'm down 3000 calories I should have lost about a pound? I do appreciate this is just one day, it's more to get an understanding as to how the maths work.

    To make the answer a bit more generic so you can calculate for different numbers when needed:

    Total calories burned with no exercise + calories burned via exercise - desired calorie deficit = target calories to eat.

    The fitbit is calculating your total calorie burn including exercise so if you know how much you actually ate in a given day, it's easy enough to calculate your deficit.
  • not_a_runner
    not_a_runner Posts: 1,343 Member
    rmgnow wrote: »
    LMAO. Your Fitbit shows you burned almost 3000 calories
    When you play high level soccer for 5 hours?
    Did you just run a marathon?
    Sorry I couldn't help myself

    I think the Fitbit is off though

    Why is this funny....?
    Fitbit is reporting estimated TDEE. It's not uncommon for men (even women) to have a TDEE of 3000+
  • 4legsRbetterthan2
    4legsRbetterthan2 Posts: 19,590 MFP Moderator
    MegaMooseEsq wrote: »
    I'm a little confused by your question: 1450 is presumably the number of calories MFP wants you to eat in a day net, correct? That number already includes a deficit that depends on the numbers you gave MFP when you set up your account - current weight, normal daily activity mode, how much you want to lose a week. So if you set it to lose 1 lb a week, you should eat 1450 every day, plus eating back the calories you burned by exercise.

    As for the fitbit numbers, that 2933 number includes the calories you've burned by being alive, plus any calories on top of that from extra steps and deliberate exercise. You'll need to link the programs so it can figure out how many extra calories you should eat (or how much extra deficit you're getting), but it's not anywhere close the numbers you're thinking. For me, I burn about 2400 on the average day, so if I burned 2933 that's an extra 533 burned. If I was eating 1450/day (which remember includes a deficit), I would absolutely want to eat some or all of that 533 calories to compensate, otherwise my deficit would be too large, which can lead to exhaustion, nutritional issues, and/or hanger.

    Does that help at all? I know it's a lot to take in. Honestly, I just take fitbit's "active minutes" and put those into MFP's exercise diary to figure out where I'm at. Hopefully while I was typing someone else came up with a better answer.

    This explanation sounds correct to me so not going to retype the same stuff out. Hopefully it makes sense to you OP.

    Also, if you are up for some reading this post is really great at explaining calorie requirements, deficits, and setting goals. I will truthfully tell you it took me a couple times through it to really understand it when I first started, but it was so helpful once I figured it all out. Hopefully it can help you too.

    http://community.myfitnesspal.com/en/discussion/1080242/a-guide-to-get-you-started-on-your-path-to-sexypants/p1

    Good luck!
  • aeloine
    aeloine Posts: 2,163 Member
    rmgnow wrote: »
    LMAO. Your Fitbit shows you burned almost 3000 calories
    When you play high level soccer for 5 hours?
    Did you just run a marathon?
    Sorry I couldn't help myself

    I think the Fitbit is off though

    On Sunday I walked 9,999 steps (4.69 miles, 44 minutes of jogging). FitBit put me at 2,953 calories burned.

    It's not EXERCISE calories. It's BREATHING/LIVING calories plus your exercise calories. As a 230+ lbs woman, I have a TDEE in the 2,200's. BMR in the 1,800's. If OP is at a higher weight and does ANY work out, OP's calories burned will be quite high.

    That said, FitBit is an ESTIMATE based on stats plugged in by user.
  • TR0berts
    TR0berts Posts: 7,739 Member
    Probably the easiest answer to your question? You don't.

    If you have your Fitbit synced to MFP, so that MFP/Fitbit calculates your Calorie goal, set MFP to Sedentary and whatever your weight loss goal is. Eat to the Caloric goal MFP gives you.
  • deannalfisher
    deannalfisher Posts: 5,600 Member
    WinoGelato wrote: »
    One of the most common mistakes people make when trying to utilize FitBit (or presumably another tracker but I've only had FitBits) and MFP is trying to overanalyze the numbers. The first thing you have to do is put some blind trust into the two systems to work together, and know that because they use different algorithms, there may always be some inconsistencies in what you see if you check and double check both systems. You also need to understand that over time, the two systems seem to get smarter, and the results become more predictable and easier to follow and trust. That said, while MANY people have had great luck with using FitBit and MFP together (I'm one of them) and find FitBit to be very accurate in predicting total calories burned, there are some who have different results and feel that FitBit overestimates their calories (less people report that it underestimates, but I've seen it). Lastly, if you enable negative calorie adjustments on MFP, it is a great safety net to ensure that you don't eat more than the calories you should in order to achieve your goals.

    I didn't really understand your example numbers so let me share some of mine.
    I'm 5'2 and 118 lbs.
    I have a desk job but I average 15K steps/day.
    MFP estimates my NEAT (non exercise maintenance calories) to be 1860 (I'm set at active b/c of my normal step count even with my desk job)
    Periodically through the day, FitBit tells MFP how many calories I'm burning from my general activity (steps, BMR, and anything that I log as "special" exercise). MFP estimates a calorie adjustment to keep my NET goal the same.
    As soon as I exceed the amount of calories MFP thinks I burn from my NEAT, the positive adjustments kick in. I eat back those adjustments, being mindful that they will change periodically throughout the day as I am more and less active.
    Since FitBit estimates my Total Calories Burned (TDEE) to be ~2200, my adjustments are usually anywhere from 250-450 cals depending on the actual day's activity level. I eat back the calories that MFP says I have left, maybe with a small buffer toward the end of the day for late downward adjustments after I go to bed.
    I've lost >30 lbs trusting the two systems - FYI, and am now in maintenance.

    So bottom line: enable negative calorie adjustments, make sure the goals are consistent in both systems, trust the adjustments within your degree of comfort, and eat back the calories. Monitor and adjust the actual results over a period of 4-6 weeks. If you are set to lose 1 lb/week and you're losing at that pace, keep it up. If slower, consider eating back less of the adjustments. If faster, consider if you want to slow it down and make the necessary changes (eat back more calories, raise goal, etc).

    analysis paralysis :)
This discussion has been closed.

Categories