Will the body really burn muscle?

[saw7988]

So I'm home for Thanksgiving and was talking with my brother, who's a biochemistry major, in his 2nd year of medical school, and studies a ton of nutrition on the side. I was telling him about my diet and how I'm eating 150+ grams of protein a day, and he thought that it was ridiculous. Apparently, the body prefers to burn fat for energy first, and muscle last. So only under rare circumstances will muscle ever be burned.

I'm not gonna even ask if you guys think he's right or not, because 100% of you will say he's wrong. But how can such a smart guy get to such a different conclusion than everyone else? What specifically do you think is wrong in his thinking? And if you do agree with him, why the disparity between the generally agreed upon principles in this forum?

[playah8er]

the body does prefer to use fat over muscle for energy, however the body cant turn fat into glucose so it has to break down muscle to get glucose..it will only do that when glycogen stores are depleted though

[drewsedg]

I have yet to read conclusive evidence on what occurs during catablism. One school of throught seems to be catabolic hormones aren't tissue specific. This means that when you are at a caloric deficit the body breaks down fat and muscle indescriminantly to create energy. Another school of thought is the body targets fat and will only break down muscle if there is a lack of protein. I honestly do not know which is true but catabolic hormones not being tissue specific seems to explain why it is so difficult to get down to ultra low body fat percentages without a lot of work.

No one is going to be able to argue against what your brother said because none of us know his reasoning. Either way though ingesting a lot of protein is important. Protein is broken down into amino acids which are the building blocks of the body. Those amino acids are used to build and repair tissue. When on a cut you have to make sure your protein levels at least do not drop below what your body needs to maintain itself or you will lose tissue. Also, when on a cut we tend to work out bodies pretty hard through exercise. This damages more tissue and requires more protein to repair it.

So regardless of how the body burns fat it is still a good ideat to take in an abundance of protein. How much is an abundance is debatable though. The research I have read says 1gram per kg of lean body mass when you put a lot of stress on the body. People here say to get 1gram for every pound which is a lot more. Some also use 0.5-1g per pound of LBM depending on activity level which seems more in line with the 1gr per kg theory.

In the end it is up to you. You can't have too much protein so why not?

[msm00b]

Doc here.

Your brother is mostly right ... which is what I've been saying here for a long time. Your body will chose muscle as it's energy source of almost last resort ... even in a huge calorie deficit. There's a lot (and I mean A LOT) if bad broscience on these forums ... You just have to shift through the crap. Most people who mention muscle catabolism on this website have no idea what they're talking about. Can it happen? Does it happen? Yes, but not under any sort of normal conditions.

Your body prefers energy in the following order:

Blood sugar
Glycogen
Fat
Muscle
Organ meat

At some point your body will opt to feed itself with fat preferentially over glucose/glycogen in order to save those energy sources that need them (red blood cells, brain, etc). Muscle breakdown to feed metabolism is a product of end stage starvation ... where fat stores have been exhausted ... and right before you start eating away at your organs. If your diet is terribly protein deficient, you may breakdown a bit of muscle for amino acids ... but this is usually minor.

As for me, I eat lots of protein fora couple of reasons. It's extremely hunger satisfying and I'd like to maximize my lean muscle gains. 1 gm per pnd per day is honestly probably excessive, but shouldn't be harmful.

[msm00b]

the body does prefer to use fat over muscle for energy, however the body cant turn fat into glucose so it has to break down muscle to get glucose..it will only do that when glycogen stores are depleted though

Bad broscience is bad.

To the OP: this is a prime example of somebody who is clueless. Unfortunately you don't need a permit to post your opinion on the intrawebs.

You do not start breaking down muscle when glycogen stores are depleted.

[Corporateminded]

I have yet to read conclusive evidence on what occurs during catablism. One school of throught seems to be catabolic hormones aren't tissue specific. This means that when you are at a caloric deficit the body breaks down fat and muscle indescriminantly to create energy. Another school of thought is the body targets fat and will only break down muscle if there is a lack of protein. I honestly do not know which is true but catabolic hormones not being tissue specific seems to explain why it is so difficult to get down to ultra low body fat percentages without a lot of work.

No one is going to be able to argue against what your brother said because none of us know his reasoning. Either way though ingesting a lot of protein is important. Protein is broken down into amino acids which are the building blocks of the body. Those amino acids are used to build and repair tissue. When on a cut you have to make sure your protein levels at least do not drop below what your body needs to maintain itself or you will lose tissue. Also, when on a cut we tend to work out bodies pretty hard through exercise. This damages more tissue and requires more protein to repair it.

So regardless of how the body burns fat it is still a good ideat to take in an abundance of protein. How much is an abundance is debatable though. The research I have read says 1gram per kg of lean body mass when you put a lot of stress on the body. People here say to get 1gram for every pound which is a lot more. Some also use 0.5-1g per pound of LBM depending on activity level which seems more in line with the 1gr per kg theory.

In the end it is up to you. You can't have too much protein so why not?

Agreed and repped, great answer!

[ryan2921]

Starvation occurs when the body is deprived of food (lack of fuel to support life). There are varying levels of starvation. The metabolic conditions that occur during starvation vary as starvation progresses.

When nutrient supply to the body is stopped, the body’s first priority is to provide glucose for the brain. In the early stages of starvation, glucose can be supplied by the breakdown of liver glycogen (stored glucose molecules). When blood levels of glucose drop, liver glycogen is broken down and shuttled to the bloodstream (Gropper 2000). The liver stores 100-110 grams of glycogen. After approximately 10-18 hours of food deprivation, liver glycogen is depleted (varies with activity levels). Gluconeogenesis also contributes to glucose production. Gluconeogenesis is the generation of glucose from non-carbohydrate sources e.g. Lactate, Pyruvate, most amino acids, Glycerol and Propionate (Hale 2005). The vast majority of gluconeogenesis takes place in the liver and to a smaller extent the kidney.

In the early stages of starvation amino acids derived from muscle protein are major contributors to gluconeogenesis. As starvation progresses and the body begins to rely more on free fatty acids and ketone bodies for fuel protein breakdown decreases.

Sparing valuable protein becomes the second priority of the body (Gropper 2000). Maintaining a specific level of protein is essential due to proteins many vital functions including the production of antibodies (to fight infection), hemoglobin (to carry oxygen to tissues) enzymes (many life-sustaining reactions) and muscle repair particularly of the heart.

As starvation continues the body begins to decrease its metabolic rate, which decreases calorie expenditure. Tissues such as the heart and skeletal muscle switch from glucose to free fatty acids for fuel. Most tissues of the body can use free fatty acids for fuel. The brain is one of the few tissues that cannot. The liver produces and releases ketone bodies as a source of energy. Ketone bodies become a major fuel for the brain when they are produced in sufficient amounts. After approximately 3 weeks of starvation, up to 75% of the brains fuel is derived from ketone bodies. It is a common myth that the brain can only use glucose for fuel. Let me repeat it is not true that the brain can only use glucose for fuel. In fact, ketogenic diets are often used for treatment with some Neurodegenerative Disorders. In the fed state, the brain uses only glucose. But, to reiterate, this changes when starvation occurs. The body’s transition to the use of ketone bodies and fatty acids for fuel lessens the demands on its protein and glucose supply. After approximately three weeks of starvation most of the body’s fuel demands are met by free fatty acids (92-93%).

[almightyares]

The energy systems in the body are the immediate, non-oxidative, and oxidative. The oxidative system is used for activities that last longer than 2 minutes. The type of fuel for oxidative energy output is glucose, glycogen, fat, and amino acids. It depends on the activity, intensity, and duration of the activity to determine which fuel is the primary source, but amino acids arent used to the extent that glycogen/glucose and fat are used, and you really shouldnt be worried that your body will be breaking down its muscles for fuel. Of course, excess protein will further decrease the need for amino acids for fuel.

Its when people go into starvation or very low calories is when the body really starts using muscle as fuel.

[trance__dreamer]

i truly believe the whole muscle loss thing is grossly over-exagerrated. :S

[idz21]

Doc here.

Your brother is mostly right ... which is what I've been saying here for a long time. Your body will chose muscle as it's energy source of almost last resort ... even in a huge calorie deficit. There's a lot (and I mean A LOT) if bad broscience on these forums ... You just have to shift through the crap. Most people who mention muscle catabolism on this website have no idea what they're talking about. Can it happen? Does it happen? Yes, but not under any sort of normal conditions.

Your body prefers energy in the following order:

Blood sugar
Glycogen
Fat
Muscle
Organ meat

At some point your body will opt to feed itself with fat preferentially over glucose/glycogen in order to save those energy sources that need them (red blood cells, brain, etc). Muscle breakdown to feed metabolism is a product of end stage starvation ... where fat stores have been exhausted ... and right before you start eating away at your organs. If your diet is terribly protein deficient, you may breakdown a bit of muscle for amino acids ... but this is usually minor.

As for me, I eat lots of protein fora couple of reasons. It's extremely hunger satisfying and I'd like to maximize my lean muscle gains. 1 gm per pnd per day is honestly probably excessive, but shouldn't be harmful.

Just to be clear...

If someone who requires 2500 hundred calories a day to maintain, eats 1800 to create a deficit, eats plenty of protein, they will not lose muscle at all? Only when this person takes drastic action and begins to starve themselves does muscle loss occur, correct?

Just want to make sure I understand what you're saying. I've read (in the nutrition forums I believe) a lot about muscle loss and how it's really inevitable if you're trying to lose weight. The only thing you can do is train with weights to keep muscle loss at its minimum. This is incorrect?

[JDkeystone]

Informative thread. Subbed.

[Mauler97]

Doc here.

Your brother is mostly right ... which is what I've been saying here for a long time. Your body will chose muscle as it's energy source of almost last resort ... even in a huge calorie deficit. There's a lot (and I mean A LOT) if bad broscience on these forums ... You just have to shift through the crap. Most people who mention muscle catabolism on this website have no idea what they're talking about. Can it happen? Does it happen? Yes, but not under any sort of normal conditions.

Your body prefers energy in the following order:

Blood sugar
Glycogen
Fat
Muscle
Organ meat

At some point your body will opt to feed itself with fat preferentially over glucose/glycogen in order to save those energy sources that need them (red blood cells, brain, etc). Muscle breakdown to feed metabolism is a product of end stage starvation ... where fat stores have been exhausted ... and right before you start eating away at your organs. If your diet is terribly protein deficient, you may breakdown a bit of muscle for amino acids ... but this is usually minor.

As for me, I eat lots of protein fora couple of reasons. It's extremely hunger satisfying and I'd like to maximize my lean muscle gains. 1 gm per pnd per day is honestly probably excessive, but shouldn't be harmful.

This is a great post, and I am very happy you are a doctor because I said the same thing here before and I got labeled with the "bro-science" label. If only I was a Doc.

More people need to see this thread and post, and it is just another reason why protein is so important for both weight loss and muscle building.

I read that once our body uses up half of our stored amino acids we die, whcih is a perfect exampe of why it is used only in an extreme starvation situations. It is literally the last resort.

[Mauler97]

Just to be clear...

If someone who requires 2500 hundred calories a day to maintain, eats 1800 to create a deficit, eats plenty of protein, they will not lose muscle at all? Only when this person takes drastic action and begins to starve themselves does muscle loss occur, correct?

Just want to make sure I understand what you're saying. I've read (in the nutrition forums I believe) a lot about muscle loss and how it's really inevitable if you're trying to lose weight. The only thing you can do is train with weights to keep muscle loss at its minimum. This is incorrect?

I would take this as true simply based of my own personal results.
Looking at my before and after pics, knowing that I increased my strength by 60-80% across the board while losing over 100lbs, I know I saved, even built muscle while losing fat. While my my calories were less than I needed, there was and is rarely a day I eat less than 200 grams of protein, usually I'm closer to 225-250 grams.

[saw7988]

Thanks for the informative responses guys. Another reason I bring this up:

My bro suggested the idea that I'm not losing weight because I'm getting too much protein. Since it's far more difficult for muscle to be broken down than everyone says, the body has no use for the crazy 150-200+ grams of protein I'm getting and it's turning into fat.

This was just a thought on his part though, not necessarily something he was trying to convince me of. Your guys' thoughts?

[retiredrunner]

Doc here.

Your brother is mostly right ... which is what I've been saying here for a long time. Your body will chose muscle as it's energy source of almost last resort ... even in a huge calorie deficit. There's a lot (and I mean A LOT) if bad broscience on these forums ... You just have to shift through the crap. Most people who mention muscle catabolism on this website have no idea what they're talking about. Can it happen? Does it happen? Yes, but not under any sort of normal conditions.

Your body prefers energy in the following order:

Blood sugar
Glycogen
Fat
Muscle
Organ meat

At some point your body will opt to feed itself with fat preferentially over glucose/glycogen in order to save those energy sources that need them (red blood cells, brain, etc). Muscle breakdown to feed metabolism is a product of end stage starvation ... where fat stores have been exhausted ... and right before you start eating away at your organs. If your diet is terribly protein deficient, you may breakdown a bit of muscle for amino acids ... but this is usually minor.

As for me, I eat lots of protein fora couple of reasons. It's extremely hunger satisfying and I'd like to maximize my lean muscle gains. 1 gm per pnd per day is honestly probably excessive, but shouldn't be harmful.

Thank you.

[JDkeystone]

My bro suggested the idea that I'm not losing weight because I'm getting too much protein. Since it's far more difficult for muscle to be broken down than everyone says, the body has no use for the crazy 150-200+ grams of protein I'm getting and it's turning into fat.

But how could you be storing fat if you're eating at a deficit? Regardless of whether you lose fat or muscle, weight loss is still a numbers game: calories in < calories out = weight loss. I think there would have to be another explanation than what he's suggesting....

[jwpawlak]

Doc here.

Your brother is mostly right ... which is what I've been saying here for a long time. Your body will chose muscle as it's energy source of almost last resort ... even in a huge calorie deficit. There's a lot (and I mean A LOT) if bad broscience on these forums ... You just have to shift through the crap. Most people who mention muscle catabolism on this website have no idea what they're talking about. Can it happen? Does it happen? Yes, but not under any sort of normal conditions.

Your body prefers energy in the following order:

Blood sugar
Glycogen
Fat
Muscle
Organ meat

At some point your body will opt to feed itself with fat preferentially over glucose/glycogen in order to save those energy sources that need them (red blood cells, brain, etc). Muscle breakdown to feed metabolism is a product of end stage starvation ... where fat stores have been exhausted ... and right before you start eating away at your organs. If your diet is terribly protein deficient, you may breakdown a bit of muscle for amino acids ... but this is usually minor.

As for me, I eat lots of protein fora couple of reasons. It's extremely hunger satisfying and I'd like to maximize my lean muscle gains. 1 gm per pnd per day is honestly probably excessive, but shouldn't be harmful.

So is it true at all ? If your body can't break down the fat stores "fast enough", then some muscle will be metabolized?

[kingof_queens]

A+ thread.

[JDkeystone]

So is it true at all ? If your body can't break down the fat stores "fast enough", then some muscle will be metabolized?

Curious to hear a scientific and well-educated response for this too......

[drewsedg]

Thanks for the informative responses guys. Another reason I bring this up:

My bro suggested the idea that I'm not losing weight because I'm getting too much protein. Since it's far more difficult for muscle to be broken down than everyone says, the body has no use for the crazy 150-200+ grams of protein I'm getting and it's turning into fat.

This was just a thought on his part though, not necessarily something he was trying to convince me of. Your guys' thoughts?

If you were to remain at the same caloric intake and lower your protein that just means you would have to raise either your carbohydrate or fat intake. What matters is your total energy in. If it is less than your total energy out you will lose weight. Eating more protein than the body needs when at a caloric deficit just means the body will start using the surplus protein as energy. Sure, some might get stored as fat but a surplus of fat or carbohydrates would too. Your body is constantly storing and burning fat throughout the day between meals. It doesn't just pile up and get added on at the end of the day. If you use more energy than you take in your will oxidize more fat than you store for the day and lose weight.

[msm00b]

If you were to remain at the same caloric intake and lower your protein that just means you would have to raise either your carbohydrate or fat intake. What matters is your total energy in. If it is less than your total energy out you will lose weight. Eating more protein than the body needs when at a caloric deficit just means the body will start using the surplus protein as energy. Sure, some might get stored as fat but a surplus of fat or carbohydrates would too. Your body is constantly storing and burning fat throughout the day between meals. It doesn't just pile up and get added on at the end of the day. If you use more energy than you take in your will oxidize more fat than you store for the day and lose weight.

It's not just about calories. Your body needs amino acids to make immunoglobulin, important enzymes, albumin ... Etc. If you lower your protein too far and really only supplement with pure carbs ... it's not unreasonable to assume that you'd body will harvest protein from the one readily available source it has: muscle. Now please don't run too far in a bad direction with this concept as I'm talking extremes here in terms of a protein deficient diet (would also have to be low in naturally occurring vegetable enzymes as well).

Your body also similarly needs fats ... and it really does need carbs to function optimally. Not exactly rocket science ... we need a balanced diet.

As for jwpawlak's comment: your body is better at breaking down fat than you give it credit for.

[th3pwn3r]

As for jwpawlak's comment: your body is better at breaking down fat than you give it credit for.

Many people have preached on this forum that a pound of fat can only provide 31 calories worth of energy per day, of course I asked for the research on this, the study if you will and it wasn't supplied to me. Things like this and the supplement companies cause an uproar and make people believe things that aren't close to being true, my favorite recommendation is that I should wake up in the middle of the night to consume a whey or casein protein shake to ward off catabolism.

[thematrixiam]

What about Amino Acids?

Say someone wanted to just take straight amino acids. skip out on a chunk of their protein. and gets some calories out of carbs and fat. Could that person theoretically eat less calories per day and get away with it?

I am going under the assumption that AAs have no calories. I could be wrong.

[Harlequinn]

It's not just about calories. Your body needs amino acids to make immunoglobulin, important enzymes, albumin ... Etc. If you lower your protein too far and really only supplement with pure carbs ... it's not unreasonable to assume that you'd body will harvest protein from the one readily available source it has: muscle. Now please don't run too far in a bad direction with this concept as I'm talking extremes here in terms of a protein deficient diet (would also have to be low in naturally occurring vegetable enzymes as well).

Your body also similarly needs fats ... and it really does need carbs to function optimally. Not exactly rocket science ... we need a balanced diet.

As for jwpawlak's comment: your body is better at breaking down fat than you give it credit for.

So then its better to do cardio in the morning to burn off extra fat? when your on a cut?

also sent ua private message dunno if u got it if you haven't let me know. its just about advice.

[whatsupfresh19]

It's not just about calories. Your body needs amino acids to make immunoglobulin, important enzymes, albumin ... Etc. If you lower your protein too far and really only supplement with pure carbs ... it's not unreasonable to assume that you'd body will harvest protein from the one readily available source it has: muscle. Now please don't run too far in a bad direction with this concept as I'm talking extremes here in terms of a protein deficient diet (would also have to be low in naturally occurring vegetable enzymes as well).

Your body also similarly needs fats ... and it really does need carbs to function optimally. Not exactly rocket science ... we need a balanced diet.

As for jwpawlak's comment: your body is better at breaking down fat than you give it credit for.

repped good info

[ChiefRocka]

Well, some posts here are indicating the muscle loss is a very rare result from a cal deficit...I will have to disagree with that. I lost muscle very quickly during a short stretch of cardio specific training. I went from repping 225lbs for 18 reps to unable to bench press 185lbs one time. All in a span of less than 6 months.

Was my protein intake too low? Yea. Was I weightlifting enough at that time? Nah. But in the blink of an eye I burned lots of muscle and wasn't starving myself or eating inadequately. It can happen a lot easier than you may think.

[msm00b]

What about Amino Acids?

Say someone wanted to just take straight amino acids. skip out on a chunk of their protein. and gets some calories out of carbs and fat. Could that person theoretically eat less calories per day and get away with it?

I am going under the assumption that AAs have no calories. I could be wrong.

'protein' is just long chains of folded amino acids. Just like 'carbs' are chained sugar molecules.

toMAYto toMAHto

[Shr3dJunki3]

Many people have preached on this forum that a pound of fat can only provide 31 calories worth of energy per day, of course I asked for the research on this, the study if you will and it wasn't supplied to me. Things like this and the supplement companies cause an uproar and make people believe things that aren't close to being true, my favorite recommendation is that I should wake up in the middle of the night to consume a whey or casein protein shake to ward off catabolism.

Nah man, you gotta be hooked up to an IV dripping protein for that. psht.

[Ivan088816]

the body does prefer to use fat over muscle for energy, however the body cant turn fat into glucose so it has to break down muscle to get glucose..it will only do that when glycogen stores are depleted though

This guys got it right.

The brain can use ketones for energy however it still requires roughly 25% of its energy to come from glucose, if you are eating low calorie, then glycogen stores will be depleted and the body will have to use protein to make glucose via gluconeogenesis. Ketones are made from fat, btw.

[acchoi90]

Sooooo
Were saying that if I don't workout for 6 months then I won't lose muscle?
(As long as I get enough protein?