Got a fit bit - looks like I've been under eating! Help!

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I just got my fitbit and it is giving me a higher calorie burn than scooby.. And that is without exercise! Scooby gives me 2200 calories for maintenance exercising 3-5 days per week. I have been wearing the fit bit and haven't been exercising and my calorie burn is around 2200-2500. When i Track it with exercise that means that my calorie burn will be around 2500-2700 or more. I have been eating at what I thought was a 15% cut at 1850 calories, when that was actually way more than 15%! I am pretty active during the day with my son, but never realized I was that active.. What do I do now? I have been eating at a 500-1000ish calorie deficit without knowing.. Help!

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  • holleysings
    holleysings Posts: 664 Member
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    I just got my fitbit and it is giving me a higher calorie burn than scooby.. And that is without exercise! Scooby gives me 2200 calories for maintenance exercising 3-5 days per week. I have been wearing the fit bit and haven't been exercising and my calorie burn is around 2200-2500. When i Track it with exercise that means that my calorie burn will be around 2500-2700 or more. I have been eating at what I thought was a 15% cut at 1850 calories, when that was actually way more than 15%! I am pretty active during the day with my son, but never realized I was that active.. What do I do now? I have been eating at a 500-1000ish calorie deficit without knowing.. Help!

    I did the same thing. Just started fixing it last week. All you need to do is breathe and start eating more. It will be ok! Your cut was just more than you had planned.
  • jyska
    jyska Posts: 728 Member
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    readjust your numbers according to your fitbit since it will be more accurate to you personally. I have a BMF and use the reports I generate from that to tweak my numbers by. Scooby is a great start and can be dead on, but if you have the means like a fitbit to track your deficit/burns etc, then use those numbers preferably. After all, that's why we buy the gadgets! :happy:
  • heybales
    heybales Posts: 18,842 Member
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    I just got my fitbit and it is giving me a higher calorie burn than scooby.. And that is without exercise! Scooby gives me 2200 calories for maintenance exercising 3-5 days per week. I have been wearing the fit bit and haven't been exercising and my calorie burn is around 2200-2500. When i Track it with exercise that means that my calorie burn will be around 2500-2700 or more. I have been eating at what I thought was a 15% cut at 1850 calories, when that was actually way more than 15%! I am pretty active during the day with my son, but never realized I was that active.. What do I do now? I have been eating at a 500-1000ish calorie deficit without knowing.. Help!

    Eat 500 more for now. Use it in typical week of normal workout routine. Establish better estimated TDEE.
    Take 15% deficit from that.

    What has been your weight loss for the 15% deficit so far?
    How many weeks?
    How many calories is the 15% deficit?

    Also be aware that FitBit knows your age, weight, and height. They are basing your foundational calorie burn on the BMR calculated from that.
    Specifically their site says Harris BMR calc, which is less accurate than Mifflin.

    Both of which are less accurate than Katch BMR calc using bodyfat%.

    So you might compare that too. If Katch BMR is decently below Harris BMR, then FitBit is overestimating your calorie burn for daily activities. But since it underestimates for true exercise, it could be a wash, just depends.

    http://www.gymgoal.com/dtool_bmr.html
  • autumnk921
    autumnk921 Posts: 1,376 Member
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    I have been having the same issue as well - My TDEE according to scooby and other sites is 2300 or so(moderate) but on my lift days the fitbit goes to 2800 each time and on rest days usually around 2300-2500 so I am wondering if I am eating too little as well.

    I am definitely going to check out the link you gave too Heybales...Thanks for sharing that. :smile:
  • BlondieBride
    BlondieBride Posts: 63 Member
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    I use a HRM for exercise.

    My weight loss has been about 1.5lbs
    I've been cutting for 5 weeks
    My 15% cut is 1850 calories

    I thought I would have lost more than 1.5lbs that is why I went out and bought the fitbit as I thought I may be underestimating my calorie burn since I seem to still be hungry with 1850-1950 calories..
  • mgmlap
    mgmlap Posts: 1,377 Member
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    Yea..I hear ya...I found out my TDEE is around 1700 and I have a very sedentary job....So i am back at 1700...and was wondering why i was starving eating 1500 calories..
  • BlondieBride
    BlondieBride Posts: 63 Member
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    And my BMR ranges from 1395-1420 calories depending on the calculator.. So only a 25 cal difference..
  • heybales
    heybales Posts: 18,842 Member
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    I use a HRM for exercise.

    My weight loss has been about 1.5lbs
    I've been cutting for 5 weeks
    My 15% cut is 1850 calories

    I thought I would have lost more than 1.5lbs that is why I went out and bought the fitbit as I thought I may be underestimating my calorie burn since I seem to still be hungry with 1850-1950 calories..

    And my BMR ranges from 1395-1420 calories depending on the calculator.. So only a 25 cal difference..

    Great on BMR being close, means the FitBit is close enough too. You are close to goal weight though, so I'd expect that.

    Great on HRM. So I'd take your FitBit with non-exercise days you've got examples of for average non-exercise TDEE, add up all your normal workout calories in a week and divide by 7. Add that to the non-exercise TDEE.

    Now you've got your best estimate of TDEE, average daily based on weekly routine.

    Use this spreadsheet to log your stats, do what I just said, and see your deficit. There is a section on "I have a FitBit, but trust the HRM for exercise calories more".

    http://www.myfitnesspal.com/topics/show/677905-spreadsheet-for-bmr-tdee-deficit-calc-macro-calc-hrm

    So 1.5 lbs weekly average lost would assume 750 cal deficit daily on average if all loss is fat.
    1850 eaten + 750 deficit = 2600 TDEE.

    So 15% of 2600 is actually 2210.

    But with so little too lose, that sounds like way to much to be losing on a weekly basis.

    Now, if you mean your total loss of that 5 wks has been 1.5 lbs, then it's likely you are still seeing improvements from exercise, and don't really know your fat loss to attempt that calc.

    In which case, skip it, and stick with FitBit non-exercise calorie burn plus HRM calorie burn to get avg TDEE.
  • heybales
    heybales Posts: 18,842 Member
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    I have been having the same issue as well - My TDEE according to scooby and other sites is 2300 or so(moderate) but on my lift days the fitbit goes to 2800 each time and on rest days usually around 2300-2500 so I am wondering if I am eating too little as well.

    I am definitely going to check out the link you gave too Heybales...Thanks for sharing that. :smile:

    Remember the whole TDEE deficit method is based on averaging out your exercise over the whole week, but eating enough on avg daily to balance that out.

    So 300-500 more on lift days, say 400 avg.
    Say 4 workout days each week.
    4 x 400 = 1600 weekly calories / 7 days = 229 avg daily exercise calories.

    229 + 2400 (2300-2500 avg) = 2629 avg TDEE based on weekly routine.

    Not sure how much to lose, 20% may be appropriate, or 15% would be better, but that the better TDEE to start at then.

    Of course, change the math depending on how many days of exercise you are talking about, but that's the method anyway.

    Oh, FitBit is the least accurate on weight lifting calorie burn. It is going purely on motion, and would never know probably 3/4's of what you are doing that cause it no motion.
  • BlondieBride
    BlondieBride Posts: 63 Member
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    Oh i meant my whole loss for the 5 weeks is 1.5lbs and my body fat is 20%.
  • splashblob
    splashblob Posts: 249 Member
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    I had the same problem last month. I ate under my TDEE for around 3 weeks then I got a fitbit. I sent my message to KIki to ask her what to do and the summary is to start eating your TDEE for another 8 weeks. You may also have to wait and average out your TDEE for a week first before you start resetting.

    Good luck to you.
  • autumnk921
    autumnk921 Posts: 1,376 Member
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    I have been having the same issue as well - My TDEE according to scooby and other sites is 2300 or so(moderate) but on my lift days the fitbit goes to 2800 each time and on rest days usually around 2300-2500 so I am wondering if I am eating too little as well.

    I am definitely going to check out the link you gave too Heybales...Thanks for sharing that. :smile:

    Remember the whole TDEE deficit method is based on averaging out your exercise over the whole week, but eating enough on avg daily to balance that out.

    So 300-500 more on lift days, say 400 avg.
    Say 4 workout days each week.
    4 x 400 = 1600 weekly calories / 7 days = 229 avg daily exercise calories.

    229 + 2400 (2300-2500 avg) = 2629 avg TDEE based on weekly routine.

    Not sure how much to lose, 20% may be appropriate, or 15% would be better, but that the better TDEE to start at then.

    Of course, change the math depending on how many days of exercise you are talking about, but that's the method anyway.

    Oh, FitBit is the least accurate on weight lifting calorie burn. It is going purely on motion, and would never know probably 3/4's of what you are doing that cause it no motion.

    Thanks Heybales - I have 30lbs to lose so I would go closer to 20% personally. I also lift 3x/wk and try to walk at least 2x/wk. I also use my HRM for any type of workouts that I do b/c I trust it more with that aspect of it. I will definitely go with what you have said and thank you for explaining it to me. I know I have been eating too little b/c I avg around 1700/dy right now b/c I was at a loss of what to do b/c my weight loss has stalled so much in the past few months. Very discouraging to say the least.

    Thanks again!!:smile:
  • lh1626
    lh1626 Posts: 241 Member
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    Great info...bump for later. I am getting my fit it in a couple of weeks