Fitbit and calorie deficit

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3dansell
3dansell Posts: 5 Member
in Health and Weight Loss
I'm new to my Fitbit Charge HR and myfitnesspal. Basically I have 100 pounds to lose and I think I have everything set up correctly. Here is some info for my question below.

- 1000 calorie deficit for a 2#/week weight loss is my plan
- "Sedentery" lifestyle set so it is projecting a 1857 calorie burn
- I set the calorie burn as personalized so I think it should change as I change ( please correct me if I'm wrong)
- I joined the gym and having been logging my exercise via the Fitbit HR
- I ate 1193 calories today but my projected calorie burn is 2985, giving me a 1985 calorie deficit.
- I log every bite of food I take... I'm pretty ocd about this.

My question is this: Do I HAVE to eat the remaining 792 calories or SHOULD I eat them?

I just want to do this the healthy way. I like the idea of eating daily calories based on my activity level, but I don't want to risk eating too much and getting frustrated with not seeing a weight loss. KWIM?

I have been doing a lot of reading and I hope I am on the right track here and haven't confused myself more.

Any comments, suggestions, encouragement and fitbit friends are welcomed.

Thanks!
Dana

Replies

  • shadow2soul
    shadow2soul Posts: 7,692 Member
    edited March 2015
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    Trust the Fitbit Calorie burn for 4-6 weeks. In 4-6 weeks, look on your Fitbit.com profile page. There you will find a 30 day burn average and a 30 day intake average. Subtract the two numbers and you will get your average daily deficit. Take that number and multiply it by 30 to get your total deficit for 30 days. Divide that number by 3500 to get an expected amount of loss. Then adjust if you lost more or less than what is expected by your numbers.

    An example (I have Fitbit Surge):

    30 Day Burn Average - 2476
    30 Day Intake Average - 2022
    30 Day Average Deficit - 454
    30 Day Total Deficit - 13,620
    Expected Loss - 3.891xxxxxx
    Actual Loss - 4lbs


    The accuracy of the calorie burn will vary from person to person. For me it's close enough to accurate, that I'm not going to need to make any adjustments to my intake until I move into maintenance. The previous models I've had (without HR) actually were underestimating by a bit more (either that or I was overestimating my food intake...but I don't think I am since I tend to not log things like crystal light).
  • ncboiler89
    ncboiler89 Posts: 2,408 Member
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    3dansell wrote: »

    My question is this: Do I HAVE to eat the remaining 792 calories or SHOULD I eat them?

    If you want to go for it. Ue them how you like. I wouldn't eat all of them back because that puts too much faith into the calorie burn estimate.

  • macgurlnet
    macgurlnet Posts: 1,946 Member
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    shadow2soul wrote: »
    Trust the Fitbit Calorie burn for 4-6 weeks. In 4-6 weeks, look on your Fitbit.com profile page. There you will find a 30 day burn average and a 30 day intake average. Subtract the two numbers and you will get your average daily deficit. Take that number and multiply it by 30 to get your total deficit for 30 days. Divide that number by 3500 to get an expected amount of loss. Then adjust if you lost more or less than what is expected by your numbers.

    An example (I have Fitbit Surge):

    30 Day Burn Average - 2476
    30 Day Intake Average - 2022
    30 Day Average Deficit - 454
    30 Day Total Deficit - 13,620
    Expected Loss - 3.891xxxxxx
    Actual Loss - 4lbs


    The accuracy of the calorie burn will vary from person to person. For me it's close enough to accurate, that I'm not going to need to make any adjustments to my intake until I move into maintenance. The previous models I've had (without HR) actually were underestimating by a bit more (either that or I was overestimating my food intake...but I don't think I am since I tend to not log things like crystal light).

    I had no idea it would show those details on the profile page - that's awesome! The weekly report is nice but this is even better. Thanks for sharing!

    ~Lyssa
  • Blueseraphchaos
    Blueseraphchaos Posts: 843 Member
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    You don't HAVE to eat those calories. if you're truly not hungry, it's okay not to eat them. It's best not to make a habit of going so far below your calories, though, since it can lead to burnout and binging later on. But just as an example, when i first started out here, i was barely netting 1,000 due to many factors. I fixed most of those problems and now easily eat 1400 a day, which leaves me able to cut calories more if i absolutely need to (if i decide to be lazy or stop working as much) to keep the same rate of weight loss. I also use a food scale to weigh my food, so i have slightly less inaccuracy, although everything is really an estimation, lol. You can always save those calories for another day when you want to splurge.
  • 3dansell
    3dansell Posts: 5 Member
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    Thank you! I appreciate the responses!
  • Merkavar
    Merkavar Posts: 3,082 Member
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    I think the suggested answer goes something like this.

    You should get as close to your calorie target as possible. Then if you do exercise you eat half of them. To pad the budget a bit assuming you eat more than you think and exercise less than you think.
  • saires_au
    saires_au Posts: 175 Member
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    I also found the 30 day calculation pretty close to accurate 3.6kg loss as fit bit 4kg actual loss so I would eat a reasonable amount back.

    Do as macgurlnet suggests and see how accurate it is for you
  • LovingLife_Erin
    LovingLife_Erin Posts: 328 Member
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    I have a fitbit flex and find that the calorie burn is pretty accurate. I generally lose what I should based on my intake and what they say my burn is. I found that my original diet meant that I also had a huge deficit, and since I have a lot to lose (and therefore will be doing it a long time) I decided to up my calories. It means I can eat more, and enjoy more treats, and still lose around 2 lbs a week. For me, that's a long term thing that I can do. If I were you, I'd enjoy a few more treats, or maybe an extra 100-300 calories a day in healthy foods. You said you ate just under 1200 today which is quite low, and it might be difficult to keep eating that low. Eating just a bit more might help ensure that you are happy and healthy, and still able to lose a good amount of weight. You don't need to force yourself to eat a ton more, but a little bit more might be a good thing. :)

  • Will210
    Will210 Posts: 201 Member
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    Blueseraphchaos wrote: »
    You don't HAVE to eat those calories. if you're truly not hungry, it's okay not to eat them. .

    I agree with this. Your body will let you know if you are eating too few calories. You will start to feel weak in during exercise. Maybe light headed when standing up and of course hungry. Trust your body on this.
  • 3dansell
    3dansell Posts: 5 Member
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    I think that I'm worried that the Fitbit stated calories burned during exercise (Charge HR) differ so much from what the machine says that I'm worried that I will eat too many calories and not lose the weight.

    For example... I weigh 242.5 pounds. I treadmill walked 2 miles in 47 minutes varying my speed from 1.8 to 3.4 and the incline from 0 to 5 varying it every quarter of a mile. The fitbit heartrate and the machine heart rate matched anywhere from 24 minutes in peak to 23 minutes in cardio. The calorie burn during exercise on the machine said 225 but my Fitbit said 482 calories burned. The machine does not take into account my age, etc, so I'm assuming that the fitbit is more accurate, but that is a huge difference!

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