Eating Below your BMR... Why is it bad?
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I always see it as the following:
BMR = requirements needed to just survive but do nothing
TDEE = requirements to go about your daily business (will change depending on whether you have a desk job or a physical job, or whatever.
If you eat more than your TDEE, you will eventually gain wait because the extra gets stored. Your deficit needs to be below your TDEE but above your BMR.0 -
If you want to lose pure fat and no muscle, do not eat below your BMR. "Weight" may come off slower, but it will be the right type of "weight" and you will look leaner and more toned instead of just a smaller version of what u were before you lost weight.0
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There is a maximum amount of fat that the body can lose at once, anything over that will be lean mass - Lyle Mcdonald had an article but I can't link from my phone, but will find it later if you haven't found it first.
That's the first piece of info I've seen that makes this make sense. I'd like to find that article.
Agreed. I would like to see it too.
Here is the article: http://www.ncbi.nlm.nih.gov/pubmed/15615615
With a summary from Reddit:Finally, we need to figure out how much of a calorie deficit you can run, in order to lose weight. To do so, note that you can lose about 31 calories worth of fat per day, per pound of fat in your body, without depleting muscle. (Source: SS Alpert, J Theor Biol. 2005 Mar 7;233(1):1-13.)[http://www.ncbi.nlm.nih.gov/pubmed/15615615[2] ]. For our example, they had 18% bodyfat at 200lbs, which is 36lbs of fat; which means our example person can run a calorie deficit of 31 calories/lb of fat * 36lbs fat = 1120 calories. Subtract this from the BMR (in the example, 2970 calories), and that is the calorie intake per day at which you will lose fat, but should not lose muscle. If you cut fewer calories, you'll probably lose fat still, but you could lose even more. If you cut more calories, you'll begin to lose muscle, which, if you're trying to maintain or build strength, is sub-optimal.
I believe the 31 cal/lb of fat/day number has since be revised down to 22 cal/lb of fat/day as well.0 -
WHen you guys are saying eating below your BMR are you including exercise??
My bmr is like 1475 but MFP tells me to eat 1240 so I am eating under it...
however i usually eat back my exercises so i end up eating around my bmr anyway... but what if i wasn't exercising?0 -
Sounds bogus to me, I believe its just made up and spread over and over on the MFP forums.
Why would your body attack muscle first instead of fat for energy? That would be quite stupid
I can see it using muscle for protein it needs, but not energy.
I don't believe your BMR is the magical cut off for your body to start eating your muscle tissue, if someone can prove to me otherwise I stand corrected
Correct. Intermittent fasting diets is a good example of your body using fat before muscles as energy. It's not until you hit the teens in bodyfat percentage should worry about muscle loss.0 -
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Sounds bogus to me, I believe its just made up and spread over and over on the MFP forums.
Why would your body attack muscle first instead of fat for energy? That would be quite stupid
I can see it using muscle for protein it needs, but not energy.
I don't believe your BMR is the magical cut off for your body to start eating your muscle tissue, if someone can prove to me otherwise I stand corrected
Correct. Intermittent fasting diets is a good example of your body using fat before muscles as energy. It's not until you hit the teens in bodyfat percentage should worry about muscle loss.
Your body uses fat as predominate energy source in a 24 hr time span already. Calorie wise, not weight wise.
It's what happens during intense energy use where it gets interesting. Doesn't take much moving up the scale of intensity to start burning more glucose calories than fat, until anaerobic.
Glucose stores are limited.
It's really about having enough glucose stores for what is needed for your activity then.
If your liver runs out, but blood sugar must be maintained, and there is no free protein floating around, then muscle will be broken down to convert to glucose. Oh sure you can get some from lactic acid, but the reason that builds up is it's slow and inefficient. Same with some fat conversion, difficult and slow.
Not a lot, doesn't take much to keep blood sugar up. Well, depending on how long and how intense your workouts are.
That all has nothing to do with bodyfat%. You can be obese, and when you go anaerobic, it's just the same as anyone else, carb burning. When you run out of glucose stores, muscle is still faster and easier to convert to glucose than lactic acid of triglycerides.
It is exactly at your BMR? No obviously not, but is there another line to draw in the sand for giving your body the best performance without some expensive tests?
That true BMR level is what your body would like to burn on taking care of required functions. Mostly supply energy to all the cells. Pulling energy out to put it back in is called perpetual motion, and we just don't have that in our body, or we could lose fat by just not eating.
Outside those normal response, if constantly in an underfed state for level of activity, the body knows how to balance things out. BMR energy use can only be reduced so much, then RMR must be reduced to save calories for BMR, the body knows unused muscle takes more energy than anything else, if something is needed to break down, there it goes.
The body will also slow you down from burning as many calories to save some. The body knows how to do adaptive thermogenesis.
Even related to how much fat energy you can supply.
http://www.ncbi.nlm.nih.gov/pubmed/156156150 -
Sounds bogus to me, I believe its just made up and spread over and over on the MFP forums.
Why would your body attack muscle first instead of fat for energy? That would be quite stupid
I can see it using muscle for protein it needs, but not energy.
I don't believe your BMR is the magical cut off for your body to start eating your muscle tissue, if someone can prove to me otherwise I stand corrected
Correct. Intermittent fasting diets is a good example of your body using fat before muscles as energy. It's not until you hit the teens in bodyfat percentage should worry about muscle loss.
Your body uses fat as predominate energy source in a 24 hr time span already. Calorie wise, not weight wise.
It's what happens during intense energy use where it gets interesting. Doesn't take much moving up the scale of intensity to start burning more glucose calories than fat, until anaerobic.
Glucose stores are limited.
It's really about having enough glucose stores for what is needed for your activity then.
If your liver runs out, but blood sugar must be maintained, and there is no free protein floating around, then muscle will be broken down to convert to glucose. Oh sure you can get some from lactic acid, but the reason that builds up is it's slow and inefficient. Same with some fat conversion, difficult and slow.
Not a lot, doesn't take much to keep blood sugar up. Well, depending on how long and how intense your workouts are.
That all has nothing to do with bodyfat%. You can be obese, and when you go anaerobic, it's just the same as anyone else, carb burning. When you run out of glucose stores, muscle is still faster and easier to convert to glucose than lactic acid of triglycerides.
It is exactly at your BMR? No obviously not, but is there another line to draw in the sand for giving your body the best performance without some expensive tests?
That true BMR level is what your body would like to burn on taking care of required functions. Mostly supply energy to all the cells. Pulling energy out to put it back in is called perpetual motion, and we just don't have that in our body, or we could lose fat by just not eating.
Outside those normal response, if constantly in an underfed state for level of activity, the body knows how to balance things out. BMR energy use can only be reduced so much, then RMR must be reduced to save calories for BMR, the body knows unused muscle takes more energy than anything else, if something is needed to break down, there it goes.
The body will also slow you down from burning as many calories to save some. The body knows how to do adaptive thermogenesis.
Even related to how much fat energy you can supply.
http://www.ncbi.nlm.nih.gov/pubmed/15615615
I was typing on my smart phone earlier so I didn't feel like typing up a whole essay and what I said was only partial truth. I agree with you that your metabolism does slow down if you constantly eat a low calorie diet and it can cause you to lose muscle mass but someone on a VLCD can prevent slowing down their metabolism and muscle loss easily just by exercising. Link below as proof that someone on a VLCD/PSMF diet can maintain muscle mass and burn only fat just by exercising.
http://forum.bodybuilding.com/showthread.php?t=121060001&highlight=psmf0 -
I've actually been wondering about this myself. I did a test last spring where I ate 1400 calories a day for about a month straight. My BMR at that time was around 1600. The goal was to see if I could gain muscle mass on a low calories diet and it was successful, I felt great actually! I did increase my calories a bit later because my level of physical activity went up and I frankly was hungry.
Just don't worry!
as long as you are feeling good that's all that really matters. 0 -
Ok let me give my own "scientific " evidence. I only got a couple of pages in before I got p*ssed off. haha So many people are fighting this and wanting the evidence, but from my own experience I know its true in some form.
I ate about 500-1000 ( Bmr 1100 ) calories a day for the majority of 2009. I went down from 9.5 to 6 stone. I gained it all back within 2 months of eating modestly and could not for the life of me what had gone wrong. I wasn't calorie counting back then but I can assure you I was eating well under 1600 cals a day when I started gaining. I now feel my metabolism was shot to hell via lack of muscle mass. I was only having cups of tea and 1 large meal a day, no snacks.
I have now eaten 1200-1800 calories a day for 4 months, I am 6.3 stone and am a size 4...where as eating below BMR for so long in 2009, I was nearly half a stone lighter and a size 6.
I was skinny - fat. My body was clearly burning way more muscle than fat. I had bones protruding everywhere but fat jiggles all over the place at the same time.
Losing the weight at a far more modest deficit, it has stayed off and I have tonnes more muscle, despite lack of exercise. Oh, and my hair fell out. My nails broke off, I stopped going to the toilet, my periods changed, and my skin was grey. Eating below BMR stops the normal functions of so many things, because your body has no energy to do these basic things for you any more.0 -
Your BMR is 1100 at age 24... that means you weigh 70 lbs. Are you a Hobbit? (Your actual BMR is probably at least 1400 so eating 500-1000 isn't just "below BMR", it's WAAAAY below BMR and into 'very low calorie/crash diet' territory.)I ate about 500-1000 ( Bmr 1100 )0 -
Your BMR is 1100 at age 24... that means you weigh 70 lbs. Are you a Hobbit? (Your actual BMR is probably at least 1400 so eating 500-1000 isn't just "below BMR ", it's WAAAAY below BMR and into 'very low calorie/crash diet' territory.)I ate about 500-1000 ( Bmr 1100 )
Can I ask where you are getting your statistics?! I am utterly offended that every time I bring up my BMR I get told Im talking bull ****. I will be posting a head shot with me next to a measuring tape soon to stop ill informed comments.
I am 4ft 9. I am 146cm long. That is smaller than some 11 year old's. I weigh around 88 lbs. My BMR is 1100. I have had it checked on several different calculators and confirmed at my doctors via the NHS formula.
People need to stop with this " That's not your BMR! Its way higher! " " If you weighed that you'd be dead " bull. Its making this place hard to be around when I'm here to give support to others and I get flamed for my own posts. There ARE small adults out there, you know...0 -
My own thread regarding BMR, at which point I then saw my GP about it and he has confirmed it.
http://www.myfitnesspal.com/topics/show/1125452-could-i-have-the-lowest-bmr-here
Edit to say: Since that thread I have had my height checked and I a 4ft 9. not 4ft 8.5 so my bmr is 1100, not 1090.0 -
http://www.bmi-calculator.net/bmr-calculator/
I put in 24 year old female and height of 4'6" and had to lower the weight to 70lbs. to get an 1100 BMR.
Even if your BMR is that low, you're talking about eating as low as half that amount. That's not what people are talking about when they say 'eating 1200 is below my BMR and that's dangerous'. For >99% of people, 1200 is not dangerous and IS below their BMR. For you, 1200 is not dangerous. And if you think 1000 is dangerous when your BMR is 1100 and you're overweight, you're wrong. 500 I'm sure is not good but that's not even half of even your tiny BMR.0 -
Well, I do not understand this at all... let's say my BMR is 5600 Kj plus I burn through other activities cca 2000 Kj. That is 7600 kj of expenditure in total. Now, I eat my BMR - that is my intake will be those 5600. 2000 Kj deficit. Sounds good. But doesn't it also mean that my body simply needs these 7600? For the activities and for the basic body functioning? It takes some energy for the aktivity, it still needs to have left something for the body functioning. Otherwise, if I eat only those 5600, and it spends 2000 kj on the aktivity }cannot stop me from walking, running, dancing), it suddenly lacks vital 2000 kJ to support the basic functions! WHich means that I simply have to eat what my body consumed for both the activity and its basic functions. The moment I eat less, I cut down on my BMR too in fact. Or do I miss anything??? How does one lose weight then if you cannot create a deficit without cutting on the BMR too in fact? I am really confused, I've been reading these posts and other webs for some time already and still do not get it... it's always about BMR and FDEE, and cutting from the FDEE, but my logic (maybe mistaken) tells me something else... uffff.... thanks for some clarification...0
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Well, I do not understand this at all... let's say my BMR is 5600 Kj plus I burn through other activities cca 2000 Kj. That is 7600 kj of expenditure in total. Now, I eat my BMR - that is my intake will be those 5600. 2000 Kj deficit. Sounds good. But doesn't it also mean that my body simply needs these 7600? For the activities and for the basic body functioning? It takes some energy for the aktivity, it still needs to have left something for the body functioning. Otherwise, if I eat only those 5600, and it spends 2000 kj on the aktivity }cannot stop me from walking, running, dancing), it suddenly lacks vital 2000 kJ to support the basic functions! WHich means that I simply have to eat what my body consumed for both the activity and its basic functions. The moment I eat less, I cut down on my BMR too in fact. Or do I miss anything??? How does one lose weight then if you cannot create a deficit without cutting on the BMR too in fact? I am really confused, I've been reading these posts and other webs for some time already and still do not get it... it's always about BMR and FDEE, and cutting from the FDEE, but my logic (maybe mistaken) tells me something else... uffff.... thanks for some clarification...
Yeah, it doesn't really make a lot of sense when you think about it that way.
Basically, to lose weight we have to consume less than we expend. If you eat less than you expend, the body uses the extra energy from stored glycogen, fat, and muscle to perform basic functions. Some people on this site use their BMR as a minimum calorie intake. This is not really based on any kind of physiological necessity but is simply used as a rule of thumb to keep from dropping their calories too low.0 -
What you're missing is that your body doesn't need calories TODAY for its activity today. You can burn 2500 calories today and eat 1500 and burn up 1000 in stored fat calories. Your BMR is not affected, at least not while you have tens of thousands of stored calories in excess fat. BMR is thrown around here like it matters to your daily intake but that is wrong. Your BMR is irrelevant, except as a stepping stone to get to an estimate of how much you burn per day. That's why no other diet plan you read or join discusses BMR, for the most part. It's good to understand that BMR is what torches most of our calories, since some people seem to think if they skip the gym they don't burn anything, but otherwise you can kind of forget it.Well, I do not understand this at all... let's say my BMR is 5600 Kj plus I burn through other activities cca 2000 Kj. That is 7600 kj of expenditure in total. Now, I eat my BMR - that is my intake will be those 5600. 2000 Kj deficit. Sounds good. But doesn't it also mean that my body simply needs these 7600? For the activities and for the basic body functioning? It takes some energy for the aktivity, it still needs to have left something for the body functioning. Otherwise, if I eat only those 5600, and it spends 2000 kj on the aktivity }cannot stop me from walking, running, dancing), it suddenly lacks vital 2000 kJ to support the basic functions! WHich means that I simply have to eat what my body consumed for both the activity and its basic functions. The moment I eat less, I cut down on my BMR too in fact. Or do I miss anything??? How does one lose weight then if you cannot create a deficit without cutting on the BMR too in fact? I am really confused, I've been reading these posts and other webs for some time already and still do not get it... it's always about BMR and FDEE, and cutting from the FDEE, but my logic (maybe mistaken) tells me something else... uffff.... thanks for some clarification...0 -
Your BMR is 1100 at age 24... that means you weigh 70 lbs. Are you a Hobbit? (Your actual BMR is probably at least 1400 so eating 500-1000 isn't just "below BMR ", it's WAAAAY below BMR and into 'very low calorie/crash diet' territory.)I ate about 500-1000 ( Bmr 1100 )
Can I ask where you are getting your statistics?! I am utterly offended that every time I bring up my BMR I get told Im talking bull ****. I will be posting a head shot with me next to a measuring tape soon to stop ill informed comments.
I am 4ft 9. I am 146cm long. That is smaller than some 11 year old's. I weigh around 88 lbs. My BMR is 1100. I have had it checked on several different calculators and confirmed at my doctors via the NHS formula.
People need to stop with this " That's not your BMR! Its way higher! " " If you weighed that you'd be dead " bull. Its making this place hard to be around when I'm here to give support to others and I get flamed for my own posts. There ARE small adults out there, you know...
I am only 4' 9" and my BMR is 1151... creating a decent weight loss deficit means finding nutrient dense low calorie foods and having a very low calorie diet .... this site is offering me a 1lb per month loss... who would be content with that?
by the way throwing around comments like 'are you a hobbit?' could be interpreted as ignorant and offensive... what if I accused you of being a hippo?0 -
So you resurrected a 6 month old thread because you took offense at 'are you a hobbit'? My sincerest apologies. My BMR is hobbit-ish, too, I'm ok with it. And I know eating under it isn't dangerous.
If I was 4'9" with 12 lbs. to lose, I don't think I'd choose MFP's plan because of the calorie floor. I wouldn't be happy with 1 lb/month either but I would think I could meet my nutritional needs at a lower calorie level than most people, due to my smaller size. Fitbit's plan doesn't use a floor and anyone can use it.0 -
Your fat is part of your body...it has a blood supply therefore part of your BMR includes the energy needed to keep the extra fat 'alive' as well...the only valid argument for eating at/above BMR is solely nutritional. It may be difficult to get all of your macros and vitamins/minerals etc under a certain calorie range but thats going to be highly individual.0
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