Fitbit is telling me my calorie intake should only be 800 calories a day?

[AA7712]

Hi, so I got a fitbit today and one of my goals is to lose 2lbs a week, I know this would cause a huge deficit but surely just 800 calories a day is not right? (I thought the bare minimum to consume is 1200 calories).

If I select 1.5lbs it says 1060 calories only. 

Meanwhile MFP says to lose 2lbs i would need to eat 1250 calories, not including any exercise.

If I do consume 1200cals then according to Fitbit i would need to exercise 500+ calories a day, and that's not including BMR.

Can someone tell me if this is correct /okay or should I find something else to follow?

[USAF-Larry]

@AA7712, counting calories is always difficult, but a simple calculation is that a pound is considered 3500 calories. So, to lose 2 pounds a week would be a deficit of 7,000 calories per week, or 1,000 calories per day.  So, if you decrease caloric intake by 500 calories per day, and increase activity to burn 500 calories a day, you have achieved 1,000 calorie deficit.  Does that give you a starting point?

[AA7712]

@USAF-Larry hi, thank you. ahh okay, makes sense. im 235lbs and 5'3 female. what should my intake be per day?

i just assumed burning 500 calories when you're only consuming 800 would be crazy. due to past experiences i really dont want to start a negative food/exercise journey again.

[UVcat]

I'm not sure if this answers your question, but I think the number of calories fitbit's Food Plan says you can eat will change throughout the day, depending on how active you are. There are some settings in the Food Tracker (where you set your deficit to 2lb/week) that can change this. Mine is set to "sedentary" so when I wake up, it bases how many calories I can eat just on my RMR. Since I am not sedentary, it then increases the amount of calories I can eat as I go about my day. I think the other setting is called "Personalized" and it tries to estimate how many calories you will burn that day total, based on previous days, etc.

So, yes, eating less than 1200 calories for the whole day is probably not a good plan, but the fitbit may end up giving you more calories than 800 by the end of the day. So, maybe plan for whatever MFP estimates you should eat, and then see how that compares to what fitibit thinks you needed for a 1000-calorie deficit? (BTW: a 1000-calorie deficit is really agressive. I decided I couldn't eat that little, myself, and opted for a 1lb/week or 0.5 lb/week deficit when I was losing weight.)

Hope that makes some sense. The way fitbit does the calories in/out tracking is pretty different from the way MFP is set up, so that may take some getting used to...

-UVc

[DavidSchneier]

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@AA7712 wrote:

@USAF-Larry hi, thank you. ahh okay, makes sense. im 235lbs and 5'3 female. what should my intake be per day?

i just assumed burning 500 calories when you're only consuming 800 would be crazy. due to past experiences i really dont want to start a negative food/exercise journey again.

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Not sure how old you are, but based on the numbers you provided your BMR is likely very close to 1,750 (the number of calories you'll burn if you simply sit in a chair or lay in bed all day without moving very much). The actual number of calories you'll burn by living a normally active life is probably somewhere closer to 2,800 calories.

While you can try and lose weight by creating an estimated deficit (that would allow you to eat more on days when you exercise), what really worked well for me, and what I strongly advocate for, is to set a daily calorie budget with an overall weekly goal. In your case, I'd start with 1,500 calories per day, or 10,500 calories per week and see how that works out over a few weeks.

Even on days when you move more than usual, by sticking to a simple and manageable budget you'll avoid complex math and are less likely to slip up and eat something(s) you shouldn't. And 1,500 affords you plenty of bandwidth to eat well without going hungry.

Also, the FitBit estimate is just about always off on active days, by as much as 15-20% (it will tell you that you burned more than you actually did). Set a budget, stick to it (and I mean really, really, really stick to it) and give it four weeks; if you're honestly and accurately tracking your food and keeping to the budget, you will see a 5-8 pound reduction.

Good luck, you can do this; no matter what, don't quit trying.

[laura.norris]

Thank you for your answer it was exactly what I was looking for. 🙂