What are the facts behind muscle loss when dieting?

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fmiller007
fmiller007 Posts: 12
in Food and Nutrition
The multiple "starvation mode" threads have got me thinking at the heart of the REAL question: Muscle loss

1.) Is it the eating of a lower amount of calories-- per se-- that trigger muscle loss, or not eating the right amount of protein gram intake, as well as the usage of those muscles via strength-training that causes it?
(It seems alot of people become confused about this when the discussion ensues, so if this could just be cleared up)

2.) How is Lean Body Mass and Muscle differentiated when holding for the results of testing "starvation mode" muscle loss over time?

I'm not sure if this is correct but I was told Lean Body Mass would include increased blood volume, connective tissues and skin necessary to support any extra weight gained or obesity, so it would make sense that eventually over time SOME inevitable Lean body Mass is lost. But it doesn't make it "muscle loss", which is what starvation mode is supposed to trigger.

My question is, how do the researchers tell the difference between this and what is actual muscle loss-- as the current standards for finding muscle vs. fat is hydrostatic testing, which again would only tell us our Lean Body Mass?



And P.S. just as a sidenote, I actually in agreement with "starvation mode", so take it easy on me as I am not taking sides.

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  • peachyxoxoxo
    peachyxoxoxo Posts: 1,178 Member
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    First question - okay, so we know that when you don't eat enough calories to fuel your body and glycogen stores are all used up, it will break down its own fat and muscle to use for energy instead. Muscle is easier for the body to break down than fat in this energy deficient state, so it tends to break that down first. Muscle is more metabolically active than fat, so this is why reduced BMRs are seen when this occurs (in the Minnesota Starvation Study, for example). However ---- this is why you need to exercise while you're losing weight. I recall reading that 30+ minutes most days is recommended to help in maintaining your lean body mass. Some studies have also shown that eating a greater amount of protein in proportion to the calorie deficit can help preserve the LBM while weight loss occurs.


    As for your second question, I'm really not sure. I've never really thought about that, and I searched online just now but wasn't able to find anything. I doubt the skin, connective tissues, and blood vessels change that much though, that it would significantly impact your percent LBM vs fat mass. Think about very obese people who lose weight and then need to have surgery for skin removal - all that excess skin is still there.
  • fmiller007
    fmiller007 Posts: 12
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    good post!
  • theartichoke
    theartichoke Posts: 816 Member
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    Saving. I hope you get great info on this. So far I've heard that we need to eat at least 1 gram of protein per pound of LBM to minimize loss while in a deficit. I've also heard that loss of LBM while in a deficit is minimal, almost negligible and that studies can't conclusively prove the loss even matters. So yeah, I know nothing. Hoping to find out though!
  • fmiller007
    fmiller007 Posts: 12
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    Okay, finally have gotten some time to post.
    However ---- this is why you need to exercise while you're losing weight. I recall reading that 30+ minutes most days is recommended to help in maintaining your lean body mass.
    When you say 30+ minutes of exercise do you mean weight-bearing resistance or just cardio ?
    Some studies have also shown that eating a greater amount of protein in proportion to the calorie deficit can help preserve the LBM while weight loss occurs.

    So, would you say it's an either or in the case of higher protein vs. higher caloric amount as far as retaining muscle or a combination of the two?

    And thirdly-- let's say you did a combination of the two, would those be canceled out if you did not follow the 30+ minutes of exercise regimen?

    As for your second question, I'm really not sure. I've never really thought about that, and I searched online just now but wasn't able to find anything. I doubt the skin, connective tissues, and blood vessels change that much though, that it would significantly impact your percent LBM vs fat mass.

    that's sort of what i thought too, but wasn't exactly sure of it. Maybe someone can come along and re-clarify on this.
    Think about very obese people who lose weight and then need to have surgery for skin removal - all that excess skin is still there.

    well, i was thinking more so in terms of when weight gained, then the excess skin that comes with it-- which may or may not be counted as lean body mass-- could possibly add to the LBM, which would make one think that it would mean a higher amount of muscle when it is simply just LBM.

    I know when I went into for my hydrostatic testing, (I'm 280) my LBM turned out to be 182 lbs, which I thought was absurd. Which would also mean that if I retained all 182 lbs. of my LBM and lost all of all of my fat (which is impossible), I could still never BE up under 182 lbs. let alone 182 lbs! Considering I'm a sophomore in college, and my sophomore year in highschool I was 170 lbs (overall counting fat + muscle)--which would put me more like at (140 lean, 30 lbs. fat), so somewhere between there and today I gained 40 lb.s of pure extra muscle!

    And apparently, this case happens all the time with people whom become over weight, so it piqued my curiosity as to what could contribute to such a mass gain in LBM despite growing only in fat! Very strange.
  • Sidesteal
    Sidesteal Posts: 5,510 Member
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    The multiple "starvation mode" threads have got me thinking at the heart of the REAL question: Muscle loss

    1.) Is it the eating of a lower amount of calories-- per se-- that trigger muscle loss, or not eating the right amount of protein gram intake, as well as the usage of those muscles via strength-training that causes it?
    (It seems alot of people become confused about this when the discussion ensues, so if this could just be cleared up)

    There are several factors that come into play.

    Training, training experience (new lifter vs experienced lifter), current physique (obese vs lean), deficit size, and likely genetics, all play a role.

    Generally speaking, the larger your deficit, the more difficult it will be to preserve lean mass. Generally speaking your protein needs increase when eating at a deficit. [/quote]
    2.) How is Lean Body Mass and Muscle differentiated

    My understanding is that your lean mass is everything that is not fat.

    My question is, how do the researchers tell the difference between this and what is actual muscle loss-- as the current standards for finding muscle vs. fat is hydrostatic testing, which again would only tell us our Lean Body Mass?

    I'm guessing they don't. I could be wrong.

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