Can my BMR be so wrong?

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Kerryalexander2011
Kerryalexander2011 Posts: 4
in Health and Weight Loss
Hi All

My calculated BMR is 1400 calories. I'm eating 200 less a day. But my weightloss has been much better than expected...3kgs in 30 days (not complaining :)! But it would suggest something like 770 deficit a day! Which would make my BMR 2170! Which is nuts!

Any insight into the maths on this? (no big change in activity level)

Thanks
K

Replies

  • Mokey41
    Mokey41 Posts: 5,769 Member
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    You're under eating and it's resulting in quick weight loss for now. Eventually that will catch up with you and you'll be back wanting to know why you aren't losing.
  • weird_me2
    weird_me2 Posts: 716 Member
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    BMR does not include any activity, so if your BMR is around 1500, if you are sedentary to lightly active (and I think most people are lightly active with day to day activites, cleaning, etc.), then you are burning around 1800-2100 calories a day which seems to be in line with your losses.
  • cjh022
    cjh022 Posts: 88 Member
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    You might be confusing your bmr for tdee... tdee (which probably is over 2000) is what you need to maintain your weight and this is what you should be eating less than to create a deficit. Your bmr is what your body requires to function if you laid in bed all day, its not recommended to eat less than your bmr without dr. supervision. The rapid weight loss is from eating so much less than your tdee. Usually a 20% deficit from tdee is a good place to start. Good luck :smile:
  • GauchoMark
    GauchoMark Posts: 1,804 Member
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    It sounds like you don't understand what BMR is.

    BMR is not the amount of calories you should eat to maintain your weight. This is why your "results are better than expected". You are supposed to take your calculated BMR, then multiply it by an activity factor to get your maintenance calories, then subtrack your deficit from that.

    For example, if your BMR is 1400 and you are sedentary, your TDEE (maintenance calories) should be 1680 cal/day. You would subract your deficit from 1680 at that point.

    Based on the info you gave, you could say that your TDEE is 2170, which means you had an activity factor of 1.55. My only words of advice in doing that is to make sure your weights and intake are correct before using that, but it does sound reasonable as long as you are exercising or have an active job.
  • Kerryalexander2011
    Kerryalexander2011 Posts: 4
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    Thanks all! That makes sense :) i'll recalculate my plan

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