Eating Below your BMR... Why is it bad?
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I've already responded to almost this exact post by about 15 other people. See posts above. In fact, my first post is a response to pretty much this exact argument. In order to lose weight, you need to have a calorie deficit. That means, you are burning more calories than you are consuming. Your body needs to make up this deficit by using your body tissue. Why would your body take it from muscle if you eat below BMR but from fat if you eat above BMR? I still haven't seen this adequately answered.
To answer this...without research to quote. Because you're working out you're actively building your muscle. Your body sees this as important to your survival. cause you're working so hard. Maybe you need stronger thighs and arms to escape predators...whatever. You're not starving so your body can focus on other things than just surviving. It now has expendable energy to put towards building muscle. It's not worried about starving to death in the near future so what's your most useless source of energy at this time? Fat yay!!!!0 -
I went to a weight loss center the other day. Gift groupon anyway the nurse said you lose weight in the order WATER weight first, Muscle second then FAT is the last to go.... Since I am so obese she said you can even go 500 calories a day... Well she gave me a 1,000 to 1,200 diet to work with. I would keep the protein side of food intake up so you don't lose muscle.... just my two cent opinion...0
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Figure 4 shows that even on 800 calorie/day diets, the weight loss was overwhelmingly water and fat. During the low-carb phase, the loss was 61.2% water, 35% fat, and 3.8% protein. During the mixed phase, the loss was smaller, mostly because less water was lost: 37.1% water, 59.5% fat, and 3.4% protein.
The subjects all had BMRs much greater than 800 calories/day. Table 2 shows BMRs ranging from 1555 to 2380, two or three times the 800 calories they ate during the experiment.
Table 2 also show the changes in weight and changes in BMR. For half of the six subjects, the two track exactly. (In other words, the BMR reduction was simply due to weight loss.) In two subjects, the BMR reduction was about 50% higher than you'd expect just from the weight loss. And in one subject, the BMR increased even though the weight was down by 13%, the exact opposite of the so-called starvation mode!
I certainly don't see that study as supporting either of these propositions:
1. Eating less than your BMR will cause you to lose muscle instead of fat.
2. Eating less than your BMR will slow down your metabolism and put you in "starvation mode."
Perhaps the second proposition was true in 2 of the 6 subjects. Not true in the other 4.0 -
I've already responded to almost this exact post by about 15 other people. See posts above. In fact, my first post is a response to pretty much this exact argument. In order to lose weight, you need to have a calorie deficit. That means, you are burning more calories than you are consuming. Your body needs to make up this deficit by using your body tissue. Why would your body take it from muscle if you eat below BMR but from fat if you eat above BMR? I still haven't seen this adequately answered.
To answer this...without research to quote. Because you're working out you're actively building your muscle. Your body sees this as important to your survival. cause you're working so hard. Maybe you need stronger thighs and arms to escape predators...whatever. You're not starving so your body can focus on other things than just surviving. It now has expendable energy to put towards building muscle. It's not worried about starving to death in the near future so what's your most useless source of energy at this time? Fat yay!!!!
I'm not quite following. What if you're not working out? How about 2 lazy people are at a calorie deficit. One is eating their BMR and the other is eating below their BMR. Is the one eating at/above their BMR losing mostly fat but the one below losing mostly muscle?
Here's the other thing. Obviously, the only true way to know how much fat and muscle I have is for someone to perform an autopsy on me. But given the crude measuring tools I have (bathroom scale), I've determined that I currently have about 147 pounds of fat on me (disgusting, I know). That means the rest we'll call LBM of 189 pounds. The last 5 pounds I lost, based on the BF% I got from the scale was overwhelmingly fat, not LBM. My LBM # (based on my BF% calc) barely moved. I lost far less than 1 pound of LBM compared the over 4 pounds of fat.
So my body seems quite happy to make up its energy deficiency from mostly fat.0 -
Figure 4 shows that even on 800 calorie/day diets, the weight loss was overwhelmingly water and fat. During the low-carb phase, the loss was 61.2% water, 35% fat, and 3.8% protein. During the mixed phase, the loss was smaller, mostly because less water was lost: 37.1% water, 59.5% fat, and 3.4% protein.
The subjects all had BMRs much greater than 800 calories/day. Table 2 shows BMRs ranging from 1555 to 2380, two or three times the 800 calories they ate during the experiment.
Table 2 also show the changes in weight and changes in BMR. For half of the six subjects, the two track exactly. (In other words, the BMR reduction was simply due to weight loss.) In two subjects, the BMR reduction was about 50% higher than you'd expect just from the weight loss. And in one subject, the BMR increased even though the weight was down by 13%, the exact opposite of the so-called starvation mode!
I certainly don't see that study as supporting either of these propositions:
1. Eating less than your BMR will cause you to lose muscle instead of fat.
2. Eating less than your BMR will slow down your metabolism and put you in "starvation mode."
Perhaps the second proposition was true in 2 of the 6 subjects. Not true in the other 4.
Thanks for reading it in more depth. Nice analysis.0 -
I went to a weight loss center the other day. Gift groupon anyway the nurse said you lose weight in the order WATER weight first, Muscle second then FAT is the last to go.... Since I am so obese she said you can even go 500 calories a day... Well she gave me a 1,000 to 1,200 diet to work with. I would keep the protein side of food intake up so you don't lose muscle.... just my two cent opinion...
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Ok, maybe I am being dense, but surely we are ALL eating below our BMR to lose weight?
MFP calculated my BMR as X. Then tells me I need to eat X - 500cals to lose 1lb per week. So I am eating below my BMR? And this is bad?
Am confused...:embarassed:
Nothing to be embarrassed about. This is a common confusion. MFP calculates the deficit not from BMR but from total energy expended in daily activities.
For a sedentary person, total energy expended on daily activities is estimated as BMR x 1.25.
For a lightly active person, total energy expended on daily activities is estimated as BMR x 1.35.
For an active person, total energy expended on daily activities is estimated as BMR x 1.45.
For an extremely active person, total energy expended on daily activities is estimated as BMR x 1.55
So for a sedentary person who wants to lose a pound a week, MFP sets the net calorie goal to (BMR x 1.25) - 500. (Except it never sets the net calorie goal lower than 1200.)
The question on this thread is whether it is necessarily bad to have a net calorie intake less than BMR.
For example, imagine a sedentary person who has a BMR of 1600. Their total energy expended on daily activities is 1600 x 1.25 = 2000.
They want to lose 1 lb per week. So, MFP sets their net calorie intake at 2000 - 500 = 1500 calories/day.
But some people say, "Never eat less than your BMR," 1600 in this case. The original poster was asking for a scientific basis for the adage "Never eat less than your BMR."
The question becomes more important for someone with a goal of losing 2 lbs per week. Say their BMR is 2000. Their total energy expended on daily activities is 2000 x 1.25 = 2500. For two pounds per week, MFP gives them a net calorie goal with a 1000 calorie deficit: 2500 - 1000 = 1500. Should they shoot for 1500 or their BMR of 2000?0 -
I'm not quite following. What if you're not working out? How about 2 lazy people are at a calorie deficit. One is eating their BMR and the other is eating below their BMR. Is the one eating at/above their BMR losing mostly fat but the one below losing mostly muscle?
Here's the other thing. Obviously, the only true way to know how much fat and muscle I have is for someone to perform an autopsy on me. But given the crude measuring tools I have (bathroom scale), I've determined that I currently have about 147 pounds of fat on me (disgusting, I know). That means the rest we'll call LBM of 189 pounds. The last 5 pounds I lost, based on the BF% I got from the scale was overwhelmingly fat, not LBM. My LBM # (based on my BF% calc) barely moved. I lost far less than 1 pound of LBM compared the over 4 pounds of fat.
So if my body seems quite happy to make up its energy deficiency from mostly fat.
Which is why bariatric surgery and a super low calorie diet works up to a point and only in certain populations. You don't have a whole lot of muscle left to breakdown and you're not actively trying to build it up. Essentiall you're a kinda well fed starving person. You're not starving so much that you're super hungry and you've got a large vat of energy in the form of fat to take from. Muscle mass is significantly less. Once you get down to a certain % of muscle your body will also hang onto that...because you need some to move around, breathe etc (it's essential to life). Your body is probably breaking down some of that muscle to fuel itself while at the same time using some fat energy to rebuild said muscle and fuel the body. I think someone mentioned already that low low calories tends to work only for obese people and only up to a point when your body starts to get worried its stores aren't enough.0 -
Thank you Treetop for explaining it so well, was worried I was doing it wrong already and am only two days into this..
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RE: the Holocaust remark.
I work with rescue horses that sometimes LOOK like Holocaust survivors. After neglect like that we can do everything in the world for them and their bodies just can't recover.
Starvation mode may not be at 1200 cals for each person, its a good guideline. But your body does go after muscle because it gets more energy per gram of muscle than it does of fat.
Believe whatever you want, but eating too few calories per day can and will eventually cause harm to your body. Anorexics look great right? They have all the energy and muscle tone in the world.
Listen to your BODY and not your stomach. Eat what you need to feel alive and energetic, but don't try to eat as few cals as possible.0 -
Ok, maybe I am being dense, but surely we are ALL eating below our BMR to lose weight?
MFP calculated my BMR as X. Then tells me I need to eat X - 500cals to lose 1lb per week. So I am eating below my BMR? And this is bad?
Am confused...:embarassed:
Nothing to be embarrassed about. This is a common confusion. MFP calculates the deficit not from BMR but from total energy expended in daily activities.
For a sedentary person, total energy expended on daily activities is estimated as BMR x 1.25.
For a lightly active person, total energy expended on daily activities is estimated as BMR x 1.35.
For an active person, total energy expended on daily activities is estimated as BMR x 1.45.
For an extremely active person, total energy expended on daily activities is estimated as BMR x 1.55
So for a sedentary person who wants to lose a pound a week, MFP sets the net calorie goal to (BMR x 1.25) - 500. (Except it never sets the net calorie goal lower than 1200.)
The question on this thread is whether it is necessarily bad to have a net calorie intake less than BMR.
For example, a sedentary person has a BMR of 1600. Their total energy expended on daily activities is 1600 x 1.25 = 2000.
They want to lose 1 lb per week. So, MFP sets their net calorie intake at 2000 - 500 = 1500 calories/day.
But some people say, "Never eat less than your BMR," 1600 in this case. The original poster was asking for a scientific basis for the adage "Never eat less than your BMR."
The question becomes more important for someone with a goal of losing 2 lbs per week. Say their BMR is 2000. Their total energy expended on daily activities is 2000 x 1.25 = 2500. For two pounds per week, MFP gives them a net calorie goal with a 1000 calorie deficit: 2500 - 1000 = 1500. Should they shoot for 1500 or their BMR of 2000?
Thank you for explaining this so well, I am only two days into MFP and was worried I was already doing it wrong. 0 -
I like the way Vaclav Gregor (Greg) put it....All credit goes to Greg.
Metabolic slow down & “Starvation modeâ€
According to diet programs, you should experience metabolic slow down or starvation mode, when you are not eating regularly or eating below your BMR (explanations differ sometimes, which I found very entertaining btw). There is no study that would support that, quite the contrary. But instead of some research that you will not understand I’ll give you the most simple and logic explanation. Just look at the pictures of people who survived the holocaust or some tragedy and have been left for months or years without food. Did they trick the metabolism and starvation mode? I don’t think so. That means that eating less or fasting will not put you into “starvation mode†and your metabolism will not slow down.
It’s really nothing to be concerned about. These things exist only to confuse you and trick you into buying more food and supplements. It’s just business, sad but true. There are tons of researches and none of them will ever speak about things like starvation mode and metabolic slow down. In this researches when people lost a lot of weight there metabolism slowed down about 100 calories. That’s one large coffee. And I would say that it didn’t slow down, it just came to the normal level from being overweight. Why? Because BMR (Basal Metabolic Rate) is calculated by your height and your lean body mass. So when you lose weight, your lean body mass number decreases.
You have a good point, but not all there yet.
Starvation mode IS real, however it is not as common as most MFPers would beleive. You need to be eating ALOT less (like, half) your BMR for a long time (like a year) to trigger it. AND, it only partially slows your metabolism, but is usually not enough to make up for the defecit. As in, if you eat at 50% your BMR, your body might slow down to need 80% of what it used to need, but it still isn't happy with you intaking 50% of your original. This is why it is still possible to starve to death. Also, side effects in the meantime are NOT good: irritability, lack of energy, etc. Losing weight is hard enough as it is, don't add all that in the mix.
I agree with you in that starvation mode is not as prevelant as most would beleive. However, it DOES happen. Still not a good idea to fiddle with.0 -
Bump0
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Good question. I don't think that your body is breaking down only fat if you eat above your BMR and only muscle if you eat below it, I think it is a mix of both either way.
That point aside, why would you want to eat fewer calories than your body needs for the most basic functioning?
Why not? You body can get calories from fat stores, its not going to just shut down if you eat under your BMR
YOUR BODY CAN'T LIVE ON JUST FAT. It needs other things like vitamins, calcium, iron, etc.
Your body WILL shut down eventually. Not from slightly eating under your BMR, but from severly doing so.0 -
For me, the TDEE/BMR business is extremely confusing.
According to the BMR calculator here, I should only be eating a bit over 1300 calories per day?
I went to a TDEE calculator and it says my TDEE is 2017.
I am currently aiming for 1500 calories a day.
From what others are saying, I think I'm doing it right. You are supposed to eat between your TDEE and BMR, correct?
I'm not in a rush to lose weight overnight, btw, I just want a sustainable, healthy lifestyle that gives me the energy for day-to-day activities and exercise.0 -
My understanding is that your BMR stands for the number of calories you would burn in a 24 hour period if you did nothing but lay still. Obviously, none (most) of us aren't going to just lay in bed all day long, so we're going to burn more than calories than our BMR just by getting out of bed and getting dressed.
If you figure out what your TDEE is, that's your maintenance level. Cutting calories from your maintenance level will cause you to lose weight. For the record, i'm sure you can lose weight eating below your BMR too, but how will you feel? Will you have enough energy?? Is it sustainable?? Why go that low if you don't really have to?? That's my two cents.......
Like this. Great explanation.0 -
Simply put....if you lose eating consistently way below your BMR you are burning muscle along with fat. If you burn muscle, you are slowing down your metabolism as you will need less calories to survive because you have less muscle. You will then most likely gain everything you lost back plus some after you stop starving yourself because your metabolism will be shot which starts the wicked cycle that many of us here on this site have fallen into.....eat, get fat, starve, eat, get fatter, starve again.......blah!
Edited after posting
So....figure out your BMR (on line calculators are not always accurate....you are better off going to get it checked at a sports lab)....then, figure out your TDEE.....whatever you eat below your TDEE will be your calorie deficit. Just don't eat below your BMR. So for me, my usual TDEE is 2750 (I wear a bodymedia to be more accurate)....my BMR is 1730. I usually aim to eat around 2000 calories which is 750 calories below my TDEE. So far so good.....0 -
I think that what that post failed to point out is that you want to eat below your BMR plus TDEE. Also, your body will not eat it's own muscle if you eat below your BMR...it will burn a 2:1 ration of fat and muscle without activity. You can rebuild muscle once you have lost weight, but the most efficient way to lose weight is through both calorie reduction and excercise.
For example, my BMR with TDEE while nothing whatsoever is 2322.42 calories per day. That is sitting on my butt doing nothing all day long. If I eat below that, for every three pounds I lose, one will be of muscle, and two will be of fat. Now, since I actually work out about 3-5 days a week, my BMR with TDEE is actually 2999.79 calories per day. Since I am also working out, I will lose less muscle than the 2:1 ration, but it will still be both.
Now, I have lost 189 lbs. That means theoretically that I have lost 126 lbs of fat and 63 lbs of fat. Heres the problem of that theory of losing muscle...since I have begun losing weight, I have gone down about 10% body fat. That means I have more lean muscle than fat than I used to have.
Once I reach my goal weight, I will go back to my BMR with TDEE for calories, but I can also continue with strength training to build more muscle and lose more bodyfat. At that point, I will be replacing a pound of fat with a pound of muscle which will reduce my body size and my body fat since fat takes up more space than muscle.
I hope this helps you to understand why that previous comment is not entirely true.0 -
im gonna take a stab in the dark, if you are not eating enough then you probably wont be able to gain muscle. if you 'go into starvation mode' you will loose weight. if you go from eating nothing to eating badly then your body may store all the calories up incase you starve it again.
i very much doubt that if u eat below you bmr you will turn into bone and fat?? still be over weight but have no muscle strength??
i would guess eating below your bmr means that if you go back to your old habit then you would perhaps put the weight on faster than if you had lost the weight slowly eating more calories??
im probably about to be proven wrong but that is how i understand it without getting to scientific lol0 -
Hi all
iI need some advice, I am really confused now...I am only 4ft 10 and weigh 50 kg and my BMI is currently 23.5 and would like it to be lower. My BMR according to MFP is 1332 and I am sedentary but walk about 3x a week so my TDEE is 1410 kcal's, so to lose weight I know you should eat 500 less to lose 1lb per week, but I know its bad to eat under 1000 and so I try and aim for 1050 net, but now I'm confused, should i be aiming for more??
I don't want to lose 0.5lb per week, i am going on holiday in 6 weeks and want to wear a bikini and feel confident, so far i have lost 2kg in 4 weeks at this calorie amount and am happy with it.
thanks
Your NET calories is what is important to lose weight, not your INTAKE. Your NET cals = your TDEE (Total Daily Energy Expenditure) - your defecit + plus exercise.
For example: if your TDEE* is 1800
You want to lose 1 lb a week, your NET has to be 1300, or a 500 cal defecit from your TDEE. You can create this defecit with exercise OR eating:
Intake 1300 - no exercise = 1300 net
Intake 1800 - 500 exercise = 1300 net
Intake 1500 - 200 exercise = 1300 net
You have to make sure you are INTAKING enough for your body, so the less you have to lose, the less you can rely on your eating alone creating the defecit and the more you have to incorporate exercise to get to your net but still be intaking enough. MFP's intake minimum is 1,200, this isn't necessarily a hard and fast rule for some of us smaller women.
If your sedenatry TDEE is 1410 and you want to lose a pound a week, you are going to need to create a 500 cal defecit either from eating or exercising, which means your NET will have to be at 910, although your INTAKE should be higher. I would suggest (without knowing much about you) to eat at 1,200 and exercise 210 cals off a day (and don't eat them back), which would create a 910 NET. YES, this net is below your BMR, but when you only have a few lbs to lose, this can't be helped. You only have to worry about damaging your metabolism if you eat significantly below your BMR for awhile, and from what I can tell about your post you probably don't have very many lbs to lose so they should be gone in a few weeks.
Make sure you are accurate in your burns like with using a Heart Rate Monitor, treadmills and average calculators can't be trusted.0 -
Simply put....if you lose eating consistently way below your BMR you are burning muscle. If you burn muscle, you are slowing down your metabolism as you will need less calories to survive because you have less muscle. You will then most likely gain everything you lost back plus some after you stop starving yourself because your metabolism will be shot which starts the wicked cycle that many of us here on this site have fallen into.....eat, get fat, starve, eat, get fatter, starve again.......blah!
Makes sense.0 -
Good question. I don't think that your body is breaking down only fat if you eat above your BMR and only muscle if you eat below it, I think it is a mix of both either way.
That point aside, why would you want to eat fewer calories than your body needs for the most basic functioning?
Why not? You body can get calories from fat stores, its not going to just shut down if you eat under your BMR
YOUR BODY CAN'T LIVE ON JUST FAT. It needs other things like vitamins, calcium, iron, etc.
Your body WILL shut down eventually. Not from slightly eating under your BMR, but from severly doing so.
No doubt that one needs to get enough vitamins and minerals. That is what the 1200 calorie per day minimum is for.
But I imagine that in the original poster's case, vitamins and minerals are not an issue. If he is asking out of practical interest, not just scientific curiosity, I'd imagine that he's trying to decide whether to eat his BMR of about 2500 or with a 1000 deficit, which would be about 2100. Unless he's eating pure junk, either is going be plenty to give him sufficient vitamins and minerals.0 -
This seems ridiculous. As long as you get enough protein in your diet you won't lose much muscle eating under BMR.0
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If there is a general acceptance that BMR is what it is (and I think there is enough science to back it up) then isn't it just common sense that eating less than that is a bad thing?0
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Human beings are, at their core, animals. Our bodies are made for survival. The reason it will start to consume muscle before fat, when faced with a large caloric deficit, is for survival. As many posters have pointed out, muscle burns more calories than fat, and so getting rid of it is the most efficient step to take. The other reason is that fat is an insulator. In the days before modern homes and food supplies, staying warm was just as important as staying fed (maybe even more so, since you can freeze to death a lot faster than you can starve to death). Our modern way of living evolved in a very short amount of time, whereas our bodies have not.
Some posters have mentioned holocaust survivors as evidence that "starvation mode" is a myth, because they have all, obviously, lost a lot of weight-- even those who didn't have any to lose. What they fail to realize, however, is that holocaust survivors did not lose that weight on their own. They were deprived of food, and their bodies essentially consumed themselves. Without being held in captivity and starved to death, only someone w/ a serious eating disorder could ever "hope" to lose weight that way. Hunger is painful, and no one could hold out for months/years (depending on how much you have to lose) and not eat what is readily available to them.0 -
If there is a general acceptance that BMR is what it is (and I think there is enough science to back it up) then isn't it just common sense that eating less than that is a bad thing?
And common sense used to say that bad air caused malaria and witches caused plague. Neither turned out to be true.0 -
And common sense used to say that bad air caused malaria and witches caused plague. Neither turned out to be true.
Again, the difference being that common sense in my statement is being applied to to an accepted scientific calculation. Apples to oranges much?0 -
Both are delicious!0
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Both are delicious!
no argument there!0 -
Good question. I don't think that your body is breaking down only fat if you eat above your BMR and only muscle if you eat below it, I think it is a mix of both either way.
That point aside, why would you want to eat fewer calories than your body needs for the most basic functioning?
Why not? You body can get calories from fat stores, its not going to just shut down if you eat under your BMR
YOUR BODY CAN'T LIVE ON JUST FAT. It needs other things like vitamins, calcium, iron, etc.
Your body WILL shut down eventually. Not from slightly eating under your BMR, but from severly doing so.
No doubt that one needs to get enough vitamins and minerals. That is what the 1200 calorie per day minimum is for.
But I imagine that in the original poster's case, vitamins and minerals are not an issue. If he is asking out of practical interest, not just scientific curiosity, I'd imagine that he's trying to decide whether to eat his BMR of about 2500 or with a 1000 deficit, which would be about 2100. Unless he's eating pure junk, either is going be plenty to give him sufficient vitamins and minerals.
Let's give my numbers. My BMR according to MFP is 2,547. However, before exercise, MFP assigns me 2180 calories to lose 2 pounds a week. This is below my BMR.
Many sites say that I can lose as much as 1% of my body weight, so I feel like I can safely lose 3.5 pounds a week (that's decreasing as I lose weight -- as of today it'd actually be 3.36). For good or bad, I'm currently averaging more than that, but it includes my first week of a 9 pound loss which probably included a lot of water.
What I've been trying to do is leave an average of 500 calories remaining after my exercise each day to average a 3 pound weight loss. I accomplish this by averaging between 2000-2400 calories a day and exercise (Power 90 plus walking). I've never eaten my BMR since I started here. I don't feel deprived or out of energy. I'm pretty sure I'm getting enough nutrients.
But according to the "You have to eat at least your BMR" people, I should be eating a minimum of 2547 calories a day and then even more if I'm exercising. This would not give me the 1000-1500 calorie deficit I need to lose 2-3 pounds a week (which again, I think is safe).0
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