Eating Below your BMR... Why is it bad?

kenny_johnson

I didn't want to hijack another thread, so I started a new one. Can someone explain this to me. Here's the quote from another user and my response. Also, if anyone has a reliable source to backup the idea/theory that you shouldn't eat below your BMR because it will either cause you to lose muscle or put you in starvation mode, can you please post them.

If you continually eat below your BMR, your body WILL find those calories from somewhere, and the most efficient place to take them from is not fat, it is muscle. Muscle burns more calories than fat, so if your body dumps muscle, it doesn't need as many calories to make it through the day. It will find a way to equal what you are giving it.

Also, help me make sense of this. In order to lose weight you HAVE TO have a calorie deficit. So whether you're eating at, above, or below your BMR, the only way you can lose weight is if at the end of the day/week, etc you are burning more calories than you're consuming.

So why would eating below your BMR mean that your calorie deficit is made up by your body from muscle, but at or above your BMR it's from fat?

Either way, it's a deficit and your body needs to make up that deficit by using some of your body tissue.

lizard053

Unless you are morbidly obese or seriously up there on the BMI for obese, eating under BMR is highly discouraged for health reasons. It can be really hard on your heart to eat less. Especially suddenly eating way less than you have been and not supplying your body enough food to survive.

If you want to lose weight, and look good while doing so, you want to lose as much fat as possible without losing a lot of muscle as well. Eating at least your BMR in calories will help you maintain the muscle you do have (exercise also greatly increases the amount of muscle you get to keep). It ensures your body has enough fuel for everything that keeps you alive AND maintaining lean body mass, bone density and higher brain functions.

If you eat under your BMR long enough, you can even start losing bone density, making your bones more brittle and easier to break.

I use WebMD to verify a lot of things I hear about diet and weight loss. I don't have any of the articles I've read over the years handy, because I don't keep them. Plus, webMD cites their sources so I rarely need to worry about finding them again!

BrittanieGo

great question, and I haven't ever found anything that makes sense to me either as far as a defecit and where it comes from. Hope there are some good answers

Athijade

BMR is what your body needs to simply survive. That is what would be burned if you just stayed in bed and did nothing. Your body NEEDS those calories to work correctly and keep the systems going. When your body can not get the calories it needs, then it looks for them wherever it can get them. That could be fat, but it also will be muscle and other systems. The thing is, it will not be just fat!

Your TDEE is where you take your deficit from. This is how much you burn based off of your daily activity.

melsinct

Your body needs X amount of calories to survive (your BMR). If you do not provide your body with this energy (calories are a unit of energy) via food, it will find it elsewhere. That “elsewhere” it finds it is your muscle (aka lean tissue).

OK, so now you are eating below your BMR and losing fat and muscle. By reducing the amount of muscle your body has, you are lowering your body’s energy requirement. This is known as killing your metabolism. This is why strength training is recommended for people losing weight. The more muscle you build, the more energy your body needs, the better your metabolism.

silverbullet07

I like the way Vaclav Gregor (Greg) put it....All credit goes to Greg.


Metabolic slow down & “Starvation mode”
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.

jtintx

BMR is what your body needs to simply survive. That is what would be burned if you just stayed in bed and did nothing. Your body NEEDS those calories to work correctly and keep the systems going. When your body can not get the calories it needs, then it looks for them wherever it can get them. That could be fat, but it also will be muscle and other systems. The thing is, it will not be just fat!

Your TDEE is where you take your deficit from. This is how much you burn based off of your daily activity.

EXACTLY!!!!!!!

drmerc

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

wild_wild_life

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?

vronster

So why would eating below your BMR mean that your calorie deficit is made up by your body from muscle, but at or above your BMR it's from fat?

Either way, it's a deficit and your body needs to make up that deficit by using some of your body tissue.

I would also like to see this answered. I get that if you eat between your BMR and TDEE, you will create a deficit and lose weight at a healthy rate. But why is your BMR the magic line between burning mostly fat and burning muscle? Inquiring minds want to know!

silverbullet07

I always go back to the anamalistic way of thinking. Animals fatten up for winter when food is scarce so that the fat can be used for energy. Is there any difference when I reduce my calories so my body will tap into my fat stores for energy to survive.

drmerc

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

sedosher

I also have a problem wrapping my brain around this. I currently consume my BMR, but net below it after exercise.

If all this is true I do not understand why MFP and other mainstream experts set goals well below what many individuals BMRs would be. The only programs I have seen that sets your calorie intake goal off of BMR and TDEE are bodybuilding or heavy lifting programs, and not all of them do.

I am by no means saying it isn't true, I just don't understand why it isn't more widely known away from MFP and used more often in mainstream fitness/weight loss if it is based in research.

lizard053

It takes more calories to support muscles than it does to support fat. If you eat below your BMR, your body canabalizes your muscles first, fat second. Unless you have a super serious overload of fat, that is. That's the reason weight loss surgeries and crash diets work, but it's only for a short while. If you want to lose a lot of weight, you need more muscle than fat, not the other way around. You'll be able to keep burning off fat if you maintain your muscle. If you lose all your muscle it will lower your TDEE, meaning you'd have to eat even less to continue to lose. And so on...

silverbullet07

And while I'm at it. Why do all the people say you "have to eat 1200 calories". It is alway at least 1200 calories. The state it before even knowing the facts of the person.

My 65 year old 4'11 mother that does nothing and trying to loose 30lbs does not have to eat 1200 calories.

get off the 1200 calorie bandwagon people. Get facts before you state 1200 calories.

cutchro

I like the way Vaclav Gregor (Greg) put it....All credit goes to Greg.


Metabolic slow down & “Starvation mode”
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.

I'm sorry... have you seen those pictures of people from the holocaust? They sure looked starved to me. No muscle, no fat, just skin and bones. What did their internal organs look like? Is that what you would like to look like?

What everyone is saying you CAN eat below... but it is NOT recommended for Health reasons. No one wants you to look like a Holocaust Survivor or end up in the hospital because your organs have shut down since they were not needed.

kaydensmom12

Your BMR is the amount of calories that you body needs in order to survive. In order for your heart to pump, for you hair and nails to grow, for you liver and kidneys to work. So if you eat below your bmr, what are you doing to your body? You are stressing it and it needs to get the calories and energy (glucose) from somewhere. When the body runs out of glucose, it can use amino acids which is what protein is made up of, for energy. So it does not pick fat b/c it is not made up with the high amount of amino acids therefore does not have the energy in it that the body needs.
So the quote is saying that the body will take muscle which lowers your calorie intake, because muscle burns more calories throughout the day than fat. The number of calories that 1lb of muscle burns throughout the day varies with the different sources, but from what I have read anywhere between 10-80 calories.
So yes you should not eat below your bmr b/c it stresses your organs. You should eat between your bmr, which is what your body needs to survive and between you tdee (the total amount of calories burned each day). This way you will have a deficit but will not be causing organ problems.

http://www.livestrong.com/article/554481-when-does-the-body-start-to-use-muscle-tissue-for-energy/
http://science.howstuffworks.com/environmental/life/human-biology/fat-cell.htm

drmerc

It takes more calories to support muscles than it does to support fat. If you eat below your BMR, your body canabalizes your muscles first, fat second. Unless you have a super serious overload of fat, that is. That's the reason weight loss surgeries and crash diets work, but it's only for a short while. If you want to lose a lot of weight, you need more muscle than fat, not the other way around. You'll be able to keep burning off fat if you maintain your muscle. If you lose all your muscle it will lower your TDEE, meaning you'd have to eat even less to continue to lose. And so on...

Do you have any proof or are you just spewing more nonsense you read on the forums?

Masterdo

I like the way Vaclav Gregor (Greg) put it....All credit goes to Greg.


Metabolic slow down & “Starvation mode”
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.

Pretty cool answer, especially considering most initial studies on starvation mode and slow metabolism actually comes from those holocaust survivors.

The first studies were done with them, how they survived (slowed metabolism) and recovered. Then nowadays studies are done with people with eating disorders, like anorexia. Take a look at any of the studies on this search, for starters : http://scholar.google.ca/scholar?hl=en&q=anorexia+metabolism&btnG=Search&as_sdt=0,5&as_ylo=&as_vis=0

The reason why it's "bad" is just because it's really not an efficient way to lose weight, especially on the long term. In a 24 hour period, your Metabolism is really what burns the most calories, not your activities, not your workouts. Circuit Training and HIIT were developed specifically to rise your metabolic rhythm for the longest period possible.

So the best route is really to eat well, eat plenty and do some well planned workouts to burn more efficiently. But, if you look at things objectively, holocaust victims surely DID lose weight, lots of it. Fat, muscles, BONES. If you are going for health and fitness though... Not the way to go.

gapm

Part of the problem in finding the research related to the effects of eating too little aside from weight loss seems to be that much of the research was done long before the internet. I remember watching a PBS show in the 1970's about research that was done either in the military or in a prison where they were looking into very low calorie diets. One of the findings was that even though everybody on the same very low calorie diet over the same period of time with the same amount of exercise, but did not have the same results. In fact, some of them lost next to nothing. The explanation was that their metabolisms had changed to accommodate the reduction in calories. I wish I could find something that could give you the details about the study without relying on my memory.

Another part of the problem is trying to find hard facts and scientific research among all the other chatter on the internet. There is a massive amount of stuff to sort through.

Edit: I did a little more looking and this article "Why do obese patients not lose more weight when treated with low-calorie diets? A mechanistic perspective" from American Journal of Clinical Nutrition, Vol. 85, No. 2, 346-354, February 2007 looked like it was relevant: http://www.ajcn.org/content/85/2/346.full

silverbullet07

I like the way Vaclav Gregor (Greg) put it....All credit goes to Greg.


Metabolic slow down & “Starvation mode”
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.

I'm sorry... have you seen those pictures of people from the holocaust? They sure looked starved to me. No muscle, no fat, just skin and bones. What did their internal organs look like? Is that what you would like to look like?

What everyone is saying you CAN eat below... but it is NOT recommended for Health reasons. No one wants you to look like a Holocaust Survivor or end up in the hospital because your organs have shut down since they were not needed.

But the “Starvation mode” idea here is that you can not loose weight in starvation mode. You have to increase those calories above the BMR. to loose. That is not true. It may be unhealthy but if you have a lot of weight to loose it can be done.