fat and muscle


by Evil
Tags: muscle
Evil
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#1
Mar26-05, 03:57 AM
P: 95
just wondering...
people usually say one can convert fat to muscle.
is this a direct mechanism of just converting or does one burn off the fat first then build the muscle?
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adrenaline
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#2
Mar26-05, 10:56 AM
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Quote Quote by Evil
just wondering...
people usually say one can convert fat to muscle.

Wrong. You can't convert fat cells to muscle cells.


is this a direct mechanism of just converting or does one burn off the fat first then build the muscle?

No such thing as burning the fat. Fat cells do multiply (called fat cell hyperplasia) and they get larger (fat cell hypertrophy) but you can't "burn" them off or reduce their numbers (except by liposuction.) In general I believe the number of fat cells are pretty much set by the time we reach adulthood (which is why obese children and teenagers have more trouble as adults losing weight since they have developed larger numbers of fat cells as well as hypertrophied fat cells).

Fat cells probably reach some biologic upper limit in number by adulthood, then cell size becomes they key factor determining the extent of obesity.

Calorie restriction and excercise atrophy or shrink the fat cells that are there and hypertrophy the muscle cells that are there.

In other words, as adults we cannot get rid of a single fat cell that we have (except once again with liposuction) but we can shrink them significantly.
misskitty
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#3
Mar26-05, 10:58 AM
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Actually it depends.

If you are physically inactive for an extended period of time, your body will burn off you muscle first because it can be converted to energy faster than fat. An example would be if you broke your leg adn had a cast for say 4 months, the muscles in the leg you broke would atrophy because you can't use it. Thats why you would need to go to physical therapy to rebuild the muscle.

Now, if you were building muscle and being very physically active, your body would burn the fat first because your body needs to sustain the muscle you have built up and the food you are ingesting is not enough. Thats why for every pound of muscle you have, you burn 100 calories of fat.

I'm almost 100% sure that's the basic idea. If I am wrong I'm sure Moonbear or one of the other Mentors will correct me. Sorry if I'm a bit off.

Pretty amazing what they teach you in P.E. isn't it?

misskitty
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#4
Mar26-05, 11:00 AM
P: 1,105

fat and muscle


Ohh, I was off! Sorry Adrenaline!

Question; how small can those fat cells become, if you can't get rid of them?
adrenaline
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#5
Mar26-05, 11:05 AM
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Remember, the term burning fat or muscle for energy (once the glycogen reserve is depelted ) does not mean the body decreases the number of fat or muscle cells, it's a complicated series of biochemical pathways that harvests energy from these cells.

Question; how small can those fat cells become, if you can't get rid of them?
Very, very small. If you look at a slice of muscle under a microscope from a fat person and compare it to a ultramarathon runner with 6% body fat, they go from looking like big fat globules to pinpoint cells with their cell wall and basic nuclear material and very very little amount of cytoplasm. It's been a while, but that is my vague recollection
misskitty
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#6
Mar26-05, 09:38 PM
P: 1,105
Wow...thats pretty small. Does your body just store the cells? Why does your body let them remain in your system if you don't need them? Or do you need them? If we do, then why can't we just burn off the ones we've got and replenish them with the food we eat? I don't mean like McDonalds Super Size Me kinda eating either...healthy responsible eating.
saltydog
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#7
Mar27-05, 08:48 AM
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Well, how about this and let me know if I'm wrong cus it's been a while:

I use to have these wall charts on intermediate metabolism. Know the kind? Anyway, I recall that the body has metabolic pathways to convert anything into anything: proteins to sugars, fats to sugars, sugars to proteins and so on. So, in a sense, we could say that fat, as tri-glycerides, can be converted to amino-acids, thus proteins, thus muscle. Ergo: fat to muscle.
misskitty
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#8
Mar27-05, 06:43 PM
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I can see where your coming from. I think this is where most of the confusion comes in. Now who is correct?
adrenaline
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#9
Mar28-05, 12:58 PM
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Quote Quote by saltydog
Well, how about this and let me know if I'm wrong cus it's been a while:

I use to have these wall charts on intermediate metabolism. Know the kind? Anyway, I recall that the body has metabolic pathways to convert anything into anything: proteins to sugars, fats to sugars, sugars to proteins and so on. So, in a sense, we could say that fat, as tri-glycerides, can be converted to amino-acids, thus proteins, thus muscle. Ergo: fat to muscle.

once again, metabolic pathwaysl (kreb's cycle) etc. where any cell can produce by-products of energy (sugars, ATP, fatty acid, ketones etc.) but the cell itself does not suddenly transmutate into another type of cell Ie: fat to muscle or muscle to fat. It's the body's way of harvesting energy through these intermediate pathways. In other words, the cellular cytology of the cell does not change but its inner "workings and machinations " so to speak, (biochemical pathways) do change depending on the energy needs of the body. Thus, the fat cells that relinquish ketones or fatty acids and glycerol go on to become fuel get taken up by the cells that need them (say skeletal muscle) which incorporates these molecules into their cytoplasmic matrix and converts them to the necessary fuel or building blocks. I believe the fat cell degredation products do not directly become amino acids but a biochemist might know more about that pathway.
adrenaline
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#10
Mar28-05, 01:04 PM
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Quote Quote by misskitty
Wow...thats pretty small. Does your body just store the cells? Why does your body let them remain in your system if you don't need them? Or do you need them? If we do, then why can't we just burn off the ones we've got and replenish them with the food we eat? I don't mean like McDonalds Super Size Me kinda eating either...healthy responsible eating.

Our whole existance until recently evolved under conditions of food scarcity so our bodies are very efficient at storing fat cells ,( although, now that evolutionary coping mechanism is killing us.) Thus, evolution has made our bodies energy storing machines rather than energy burning machines. It is no wonder, our bodies do not relinquish those "hard earned" fat cells!
saltydog
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#11
Mar29-05, 08:03 AM
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Quote Quote by adrenaline
Our whole existance until recently evolved under conditions of food scarcity so our bodies are very efficient at storing fat cells ,( although, now that evolutionary coping mechanism is killing us.) Thus, evolution has made our bodies energy storing machines rather than energy burning machines. It is no wonder, our bodies do not relinquish those "hard earned" fat cells!
Hello adrenaline, I know you said no fat to muscle and I said the converse and really I'm not sure. Would like to know though. Anyway, you bring up an interesting feature of evolution. I don't think our coping mechanism for food scarcity is killing us. Let's see . . . how do I put this . . . well, it's eliminating the less-fit to say it bluntly: those genotypes less able to adapt to a food-surplus environment will be weeded out and those better able to adapt will pass on their genes. But that's Ok as that type of mechanism, however brutal, has give us the opportunity to experience life: we are the end product of that brutality and if we are to give future generations a similar chance, it should remain so.
adrenaline
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#12
Mar29-05, 08:58 AM
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Quote Quote by saltydog
Hello adrenaline, I know you said no fat to muscle and I said the converse and really I'm not sure. Would like to know though. Anyway, you bring up an interesting feature of evolution. I don't think our coping mechanism for food scarcity is killing us. Let's see . . . how do I put this . . . well, it's eliminating the less-fit to say it bluntly: those genotypes less able to adapt to a food-surplus environment will be weeded out and those better able to adapt will pass on their genes. But that's Ok as that type of mechanism, however brutal, has give us the opportunity to experience life: we are the end product of that brutality and if we are to give future generations a similar chance, it should remain so.

Yes, that is a very interesting way of looking at it!


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