Does Body Fat percentage effect your metabolism?

24

Replies

  • jwdieter
    jwdieter Posts: 2,582 Member

    You require fewer calories because you have 40lbs less mass, not because you are leaner.

    At a given weight, the leaner body will require more calories to maintain than the less lean body (all else being equal).

    So the correct statement is "The leaner you are, the MORE calories your body needs to maintain itself."

    Er, no - what you are driving at is that the greater your % LBM, the more calories you need to maintain. However, this is not the same as "the leaner you are" in this example. You are talking about two individuals at the same mass, but with differing muscle percentages. SS was meaning the same individual having lost mass (which could mostly be fat).

    For example: You start off at 250lbs and 35% bodyfat and diet to say 165lbs, 15% bodyfat - you will require far less energy to maintain your mass at 165lbs, 15% lbm than you did at 250lbs....

    Semantics fight! Round 5, go!
  • jonnythan
    jonnythan Posts: 10,161 Member

    You require fewer calories because you have 40lbs less mass, not because you are leaner.

    At a given weight, the leaner body will require more calories to maintain than the less lean body (all else being equal).

    So the correct statement is "The leaner you are, the MORE calories your body needs to maintain itself."

    Er, no - what you are driving at is that the greater your % LBM, the more calories you need to maintain. However, this is not the same as "the leaner you are" in this example. You are talking about two individuals at the same mass, but with differing muscle percentages. SS was meaning the same individual having lost mass (which could mostly be fat).

    For example: You start off at 250lbs and 35% bodyfat and diet to say 165lbs, 15% bodyfat - you will require far less energy to maintain your mass at 165lbs, 15% lbm than you did at 250lbs....

    The leaner you are, the more calories you require to maintain.

    This is a simple fact. All else being equal, a lean body requires more calories than a less lean body.
  • Dang ancestors.
  • SideSteel
    SideSteel Posts: 11,068 Member

    You require fewer calories because you have 40lbs less mass, not because you are leaner.

    At a given weight, the leaner body will require more calories to maintain than the less lean body (all else being equal).

    So the correct statement is "The leaner you are, the MORE calories your body needs to maintain itself."

    Er, no - what you are driving at is that the greater your % LBM, the more calories you need to maintain. However, this is not the same as "the leaner you are" in this example. You are talking about two individuals at the same mass, but with differing muscle percentages. SS was meaning the same individual having lost mass (which could mostly be fat).

    For example: You start off at 250lbs and 35% bodyfat and diet to say 165lbs, 15% bodyfat - you will require far less energy to maintain your mass at 165lbs, 15% lbm than you did at 250lbs....

    The leaner you are, the more calories you require to maintain.

    This is a simple fact. All else being equal, a lean body requires more calories than a less lean body.

    In practice, the majority of people who go from not lean to lean will not have "all else being equal". They will weigh much less in most contexts.
  • LYNN8SUPERSTARZS
    LYNN8SUPERSTARZS Posts: 21 Member
    Muscles takes up less space than fat. So two people the same weight and height can look very differant because of there body fat percentages.
  • QuietBloom
    QuietBloom Posts: 5,413 Member

    You require fewer calories because you have 40lbs less mass, not because you are leaner.

    At a given weight, the leaner body will require more calories to maintain than the less lean body (all else being equal).

    So the correct statement is "The leaner you are, the MORE calories your body needs to maintain itself."

    Er, no - what you are driving at is that the greater your % LBM, the more calories you need to maintain. However, this is not the same as "the leaner you are" in this example. You are talking about two individuals at the same mass, but with differing muscle percentages. SS was meaning the same individual having lost mass (which could mostly be fat).

    For example: You start off at 250lbs and 35% bodyfat and diet to say 165lbs, 15% bodyfat - you will require far less energy to maintain your mass at 165lbs, 15% lbm than you did at 250lbs....

    The leaner you are, the more calories you require to maintain.

    This is a simple fact. All else being equal, a lean body requires more calories than a less lean body.

    In practice, the majority of people who go from not lean to lean will not have "all else being equal". They will weigh much less in most contexts.

    True, but it illustrates the principle without introducing any more confusing variables. This stuff can be confusing and the simplest explanation is usually the best one IMO.
  • lithezebra
    lithezebra Posts: 3,670 Member
    generally speaking, your body does NOT like being lean.

    My body seems to be fine with it, if you consider 17-18% BF to be lean for a female body. It's too lean for some of the BF calculators that take my age into account, but it's easy to maintain. I think that it takes a lot of people a while to get used to eating less.
  • jonnythan
    jonnythan Posts: 10,161 Member
    generally speaking, your body does NOT like being lean.

    My body seems to be fine with it, if you consider 17-18% BF to be lean for a female body. It's too lean for some of the BF calculators that take my age into account, but it's easy to maintain. I think that it takes a lot of people a while to get used to eating less.

    It takes work to stay that way, which is what he's getting at. Your body tries to store calories as fat whenever it gets the chance. Keeping lean means not giving it the opportunity by maintaining calorie intake and exercising.
  • auntiebabs
    auntiebabs Posts: 1,754 Member
    calculate-my-body-fat-percentage.gif
    the chart is from the world health organization, which bases it these categories on a variety of HEALTH. factors

    Trainers use a different chart, which does not account for age.
    Think about it, it's how they sell there services.
    1) They want to acheive more extreme results so they can show you their track record of "success" and
    2) The more extreme your goals are the easier it is to sell you on their services.
  • QuietBloom
    QuietBloom Posts: 5,413 Member
    Unless anyone has evidence to the contrary, I don't think it's necessary to assume that the healthy body fat% should rise as men and women age. I think it probably does statistically, but then so does weight and we all know that adding weight as the years go on is NOT inevitable.
  • heybales
    heybales Posts: 18,842 Member
    Unless anyone has evidence to the contrary, I don't think it's necessary to assume that the healthy body fat% should rise as men and women age. I think it probably does statistically, but then so does weight and we all know that adding weight as the years go on is NOT inevitable.

    So true, what they consider healthy does though. And I'm sure with all the other stresses on the body, having less fat as you get older would probably be better.

    Same claim made that metabolism goes down as you age. Well sure, if you lose muscle mass due to less use of muscles, as the average population has happen.
    But that doesn't mean it has to happen.
    Now, I have seen the "studies" (really case studies on individuals), that at a certain point (which would vary of course), the metabolism takes a nose dive even for those that are active, about the time their body stops being able to recover as well, they get sick more, heal slower, ect.
    So not that their system all of a sudden after 80 years figured out how to become more efficient doing everything it needed to, but rather it stopped doing as much as often.

    Same claim made regarding HRmax, lowers as you age, as the formula's show. Well, no, doesn't need to if you maintain a cardio fitness program and keep it up. My tested has not lowered in many years. Shoot, I'm 26 by standard formula. Huh, how come I don't feel 26.....
  • QuietBloom
    QuietBloom Posts: 5,413 Member
    Heybales, yes, I have read that maximum heart rate doesn't decrease with age as they used to assume, in fit individuals. Another great example of how these recommendations and calculations can be quite off in fit individuals. I'm thinking of the bodybuilder with 8% body fat who is told by his physician that he is 'obese' and better watch his weight. :noway:
  • ninerbuff
    ninerbuff Posts: 48,488 Member
    Well yes. If you're 150lbs lean body weight and 30% bodyfat vs 150lbs lean body weight and 15% body fat, the higher body fat% will have a higher metabolic rate.


    A.C.E. Certified Personal and Group Fitness Trainer
    IDEA Fitness member
    Kickboxing Certified Instructor
    Been in fitness industry for 30 years and have studied kinesiology and nutrition
  • Azdak
    Azdak Posts: 8,281 Member
    calculate-my-body-fat-percentage.gif
    the chart is from the world health organization, which bases it these categories on a variety of HEALTH. factors

    Trainers use a different chart, which does not account for age.
    Think about it, it's how they sell there services.
    1) They want to acheive more extreme results so they can show you their track record of "success" and
    2) The more extreme your goals are the easier it is to sell you on their services.

    Maybe yes, maybe no. Those "recommendations" are ranges that are somewhat subjective in that they represent interpretations of scientific literature. While they represent a majority opinion, they do not have unanimous support.

    Other factors--such as appearance and physical comfort--are not considered. From a scientific, health standpoint they should not be considered, but in the real world with real people, those factors are VERY important. I have never met anyone who was 35% fat and said -- "wow, I look and feel great". (Unless they started out at 50% fat--and even then they weren't satisfied with 35%).

    As a health and fitness professional who works in a medically-based facility, it's something I have to deal with--with real people, not charts--every day. All of the factors--not just the WHO "recommendations"-- have to be taken into consideration. That includes the clients overall health and medical needs (e.g. if you are diabetic or have joint problems, 35% fat is not an effective target), their personal appearance goals, and their overall fitness and performance goals (ranging from doing sports activities to being able to keep up with a tour group to being able to play with grandchildren).

    I think it is an overly broad generalization to imply that all trainers try to manipulate their clients with dishonest and unreasonable "goals" just to "sell there (sic) services".

    In 30 years, I've never done it. Not once. And neither has anyone I have ever worked with (I will admit I have never worked in a commercial gym, so things might be different there).
  • Azdak
    Azdak Posts: 8,281 Member
    The studies that I have read show that the "increased metabolism" that comes from exercise is due almost solely to changes in muscle mass. There doesn't appear to be any independent, permanent change in "metabolism" that can be ascribed to exercise alone--either cardio or strength training.

    I have not researched the topic extensively, but I don't recall seeing any studies that looked specifically at changes in resting metabolism between people with different proportions of muscle to fat. It seems logical that, if you have two people who weigh 150 pounds, that the one with the higher amount of muscle mass would have a higher resting metabolism.

    However, there are two things to consider:

    1. Just because someone has a lower body fat %, that doesn't mean they have a higher amount of muscle mass. Fat free mass consists of a lot of things that aren't muscle -- organs, bones, water, etc.

    2. It would take a considerable amount of muscle mass to make a noticeable difference in metabolism. If you have someone who is 235lbs and 10% fat vs someone who is 235 lbs and 25% fat, there is probably a difference--but that's because you are looking at roughly a 30lb difference in muscle mass. The majority of people will not fall into that category.
  • wild_wild_life
    wild_wild_life Posts: 1,334 Member
    My understanding is that increased LBM (specifically muscle mass) affects BMR very little, something to the effect of 10-20 cals per lb of muscle per day. Not sure though, don't have the stats in front of me.

    ETA: According to the paragon of scientific knowledge, Livestrong.com, a lb of fat burns 2-3 cals per day and a lb of muscle 7-10 cals per day. So you will earn up to 8 additional cals max for trading them out.

    http://www.livestrong.com/article/438693-a-pound-of-fat-vs-a-pound-of-muscle/
  • lithezebra
    lithezebra Posts: 3,670 Member
    generally speaking, your body does NOT like being lean.

    My body seems to be fine with it, if you consider 17-18% BF to be lean for a female body. It's too lean for some of the BF calculators that take my age into account, but it's easy to maintain. I think that it takes a lot of people a while to get used to eating less.

    It takes work to stay that way, which is what he's getting at. Your body tries to store calories as fat whenever it gets the chance. Keeping lean means not giving it the opportunity by maintaining calorie intake and exercising.

    The only reason it takes work to stay that way is that we live in a society in which food is plentiful for most people. If we lived even 100 years ago, most of us would be working hard to get enough food to live.
  • QuietBloom
    QuietBloom Posts: 5,413 Member
    2. It would take a considerable amount of muscle mass to make a noticeable difference in metabolism. If you have someone who is 235lbs and 10% fat vs someone who is 235 lbs and 25% fat, there is probably a difference--but that's because you are looking at roughly a 30lb difference in muscle mass. The majority of people will not fall into that category.

    The difference for me was about 150 kcalories more I could eat per day once I figured my BMR using my fat % vs other more generic formulas. I think that is quite a lot actually.
  • wild_wild_life
    wild_wild_life Posts: 1,334 Member
    generally speaking, your body does NOT like being lean.

    My body seems to be fine with it, if you consider 17-18% BF to be lean for a female body. It's too lean for some of the BF calculators that take my age into account, but it's easy to maintain. I think that it takes a lot of people a while to get used to eating less.

    It takes work to stay that way, which is what he's getting at. Your body tries to store calories as fat whenever it gets the chance. Keeping lean means not giving it the opportunity by maintaining calorie intake and exercising.

    The only reason it takes work to stay that way is that we live in a society in which food is plentiful for most people. If we lived even 100 years ago, most of us would be working hard to get enough food to live.

    True, which is why, physiologically speaking, the body is quick to accumulate fat reserves when given the chance.