Ok, so what happens when you eat less than your BMR?

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  • ianrea1
    ianrea1 Posts: 6 Member
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    I think what people are getting at with "starvation mode" is that if you eat too few calories, your BMR goes down, which makes it more difficult to lose weight. Your BMR is the rate at which you burn calories without doing any exercise, but if you're not eating enough, your body tries to protect itself by making you feel sluggish and weak, and by slowing down your internal processes. This means that you end up being less active and burn fewer calories in the course of a day than you would otherwise.

    Plus, a starvation diet will make you miserable and sap your willpower, so it's probably counterproductive in the long run if you're trying to lose weight, because you may just end up cracking and abandoning your diet altogether.
  • Aaron_K123
    Aaron_K123 Posts: 7,122 Member
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    I've heard both sides here - that as long as there's a calorie deficit, you WILL lose weight, but others say that if you don't eat enough calories your body won't have energy to burn fat?
    I'd like to hear other's info on this!

    There is no debate there. One group is right, the other group are completely illogical and make no sense. I'll leave it up to you to determine which is which. Hint, the one that makes no sense is the one that is nonsense.
  • ianrea1
    ianrea1 Posts: 6 Member
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    Note also that there are all sorts of hormonal things that push your BMR up and down, and that the amount and type of foods that you eat contribute to this. If you want a more exact calculation on what will happen if you make diet and exercise changes, here's tool from the National Institutes of Health that asks for a bunch of inputs, but gives you a more precise idea of what will happen than the back of the envelope calculations on MFP.
    http://www.niddk.nih.gov/research-funding/at-niddk/labs-branches/LBM/integrative-physiology-section/body-weight-simulator/Pages/body-weight-simulator.aspx
  • 3dogsrunning
    3dogsrunning Posts: 27,167 Member
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    But concern for "eating too few calories" usually starts at 800 or 1000 or in the case of MFP, 1200. Not BMR.

    I tend to be concerned about how many calories vs how active, not just specific numbers. You can eat above BMR and still be eating too few calories if one is very active.
    The authorities recommend not eating at a deficit that causes you to lose more than 2 lbs/week, on average. Your BMR estimate might be above or below that but it's just a number and should have no bearing on one's intake decision, except possibly to help estimate how much you burn in a day.

    And 2lbs a week is another one of those numbers. For some it is a completely appropriate goal. For others, it is far too aggressive. For someone close to their goal weight a 1000 calorie deficit is extremely aggressive.
  • WalkingAlong
    WalkingAlong Posts: 4,926 Member
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    In my opinion that is another MFPism. In the actual industry of professionals in the field, 1000 calories is considered a safe deficit level for virtually anyone as long as it doesn't put you below whatever number they consider a safe floor value, usually 1000-1200. And they mean that you can up your activity to create a 1000 calorie deficit if it does put you close to the floor value. Only here are smaller people encouraged to take on only tiny deficits.
  • 3dogsrunning
    3dogsrunning Posts: 27,167 Member
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    In my opinion that is another MFPism. In the actual industry of professionals in the field, 1000 calories is considered a safe deficit level for virtually anyone as long as it doesn't put you below whatever number they consider a safe floor value, usually 1000-1200. And they mean that you can up your activity to create a 1000 calorie deficit if it does put you close to the floor value. Only here are smaller people encouraged to take on only tiny deficits.

    I'm not sure I exactly follow what you are saying. But I do know that the advice for more modest deficits goes well beyond MFP.
  • WalkingAlong
    WalkingAlong Posts: 4,926 Member
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    I would be interested in seeing any authoritative source, WedMD, Mayo Clinic, WW, any reputable diet book or plan, any published article or book, any reputable site, that advises against eating below BMR or that says only the very overweight or obese can safely run 1000 calorie per day deficits or aim for losing 2 lbs/week.
  • Iwishyouwell
    Iwishyouwell Posts: 1,888 Member
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    I've heard both sides here - that as long as there's a calorie deficit, you WILL lose weight, but others say that if you don't eat enough calories your body won't have energy to burn fat?
    I'd like to hear other's info on this!

    This is a participant in the famous Minnesota Starvation Experiment.
    2nv5yd4.jpg

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