What role does metabolism actually play in weight loss?

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  • psuLemon
    psuLemon Posts: 38,420 MFP Moderator
    Ok, so new question relating to metabolism. If it's true that metabolism has very little to do with weight loss / gain, why is it that older people seem to have a much harder time losing weight or getting in shape? Is this just another societal myth, or do they really find it more difficult due to a slowing down metabolism? Or are there other factors of which I'm unaware?

    There is some metabolic slow down as you age (most will lose muscle) but the difference is a few hundred calories. On top of that, they dont move as much as many younger people their equivalent size. Due to this, many older people have a harder time creating a deficit from their tdee. You will also see this in those who are fairly lean as precision is required a bit more.

    But there are many cases of people on here in their 60s that lose weight effectively. Some of them actually lose at a fairly high calorie range and others at lower ranges.

  • tincanonastring
    tincanonastring Posts: 3,944 Member
    psulemon wrote: »
    Ok, so new question relating to metabolism. If it's true that metabolism has very little to do with weight loss / gain, why is it that older people seem to have a much harder time losing weight or getting in shape? Is this just another societal myth, or do they really find it more difficult due to a slowing down metabolism? Or are there other factors of which I'm unaware?

    There is some metabolic slow down as you age (most will lose muscle) but the difference is a few hundred calories. On top of that, they dont move as much as many younger people their equivalent size. Due to this, many older people have a harder time creating a deficit from their tdee. You will also see this in those who are fairly lean as precision is required a bit more.

    But there are many cases of people on here in their 60s that lose weight effectively. Some of them actually lose at a fairly high calorie range and others at lower ranges.

    Not to mention the loss of lean muscle mass and changes in bone density that often accompany old age. As the ratio of body tissue changes, I can see how the calorie burning process would be affected, even beyond a lower BMR. For one, the exercise recovery process would burn fewer calories, right, with a lower amount of lean muscle mass?
  • psuLemon
    psuLemon Posts: 38,420 MFP Moderator
    psulemon wrote: »
    Ok, so new question relating to metabolism. If it's true that metabolism has very little to do with weight loss / gain, why is it that older people seem to have a much harder time losing weight or getting in shape? Is this just another societal myth, or do they really find it more difficult due to a slowing down metabolism? Or are there other factors of which I'm unaware?

    There is some metabolic slow down as you age (most will lose muscle) but the difference is a few hundred calories. On top of that, they dont move as much as many younger people their equivalent size. Due to this, many older people have a harder time creating a deficit from their tdee. You will also see this in those who are fairly lean as precision is required a bit more.

    But there are many cases of people on here in their 60s that lose weight effectively. Some of them actually lose at a fairly high calorie range and others at lower ranges.

    Not to mention the loss of lean muscle mass and changes in bone density that often accompany old age. As the ratio of body tissue changes, I can see how the calorie burning process would be affected, even beyond a lower BMR. For one, the exercise recovery process would burn fewer calories, right, with a lower amount of lean muscle mass?

    You make a solid point with recovery. Long exercise recovery times can also make it harder to work out as someone who is 20 or 30 years younger.... essentially leading to a lower tdee.


    But yea lower lbm = slower metabolism = lower starting point in the energy balance equation.
  • senecarr
    senecarr Posts: 5,377 Member
    So I'm clear - There is no such thing as fast metabolism/ slow metabolism? I ask because I've always thought I had a pretty fast metabolism. Even before I started CICO I was on the sidelines of, "normal weight/overweight" on the BMI chart and I swear I was eating over 3k calories a day. I started doing CICO and set it to lose .5 pounds a week and I averaged over 1 pound a week for 16 weeks and I always thought it was because I had a faster than usual metabolism.

    Some people have a higher or lower BMR which is basically your 'metabolism'. Factors that influence this are lean muscle mass, height, age etc. So if you feel like you have a faster metabolism it may be you're young tall and lean.

    Let's look at 2 case studies:

    If you are MALE, 175cm, 95 kg, 25 yrs your BMR is about 2079 calories

    If you are FEMALE, 163cm, 60kg, 25 yrs your BMR is about 1414 calories.

    That's a difference of 665 calories. That's a lot more food you can eat.

    I don't believe this is correct. You may have misunderstood me. What I'm saying is, I found what calculators said was my BMR or TDEE and what I'm suppose to lose eating 1800 calories (sometimes more) a day and I have lost double more than I was suppose to. I feel I actually do have a fast metabolism than I took advantage of for too many years.

    Given all the factors that go into creating a calorie deficit, it's much more likely that your counts are off in the number of calories you're eating, your activity level, and/or your exercise calories than it is that your have a metabolic rate which deviates significantly than the general population.

    Entirely plausible that I'm off somewhere in my calculations.

    With all the issues I see on here with other people logging, weighing, measuring and how easy it is for me to accidentally lose twice as fast as I wanted to... Isn't that entirely plausible to say I MAY have a faster metabolism?

    I don't think we have enough information to make that determination. I can't even see your diary to check how well you log or if you weigh your food, I don't know what your exercise burns look like or how much of them you eat back, etc. Even without that information, I still think it's more likely your calculations are off than you have a significanty higher metabolic rate. Or maybe you have a tapeworm.

    Damnit... I probably have a tapeworm.

    Similar to a tapeworm, if you had an actual metabolic condition that made anywhere near the difference you're coming up with, you'd almost assuredly have other signs of it.
    For example, Lizzie Velasquez (https://en.wikipedia.org/wiki/Lizzie_Velásquez) has a genetic condition where she can't gain on a 5,000-8,000 calories a day. She's a 1 in 7 billion kind of metabolism though, and she has numerous other issues that demonstrate her metabolism.
    Off the top of my head, I'd say if you had a BMR that was actually around 3,000-4,000 calories, doing any kind of exercise with intensity would leave your body unbearably hot as you probably would go past the ability of a human body to remove heat.
  • SLLRunner
    SLLRunner Posts: 12,942 Member
    senecarr wrote: »
    So I'm clear - There is no such thing as fast metabolism/ slow metabolism? I ask because I've always thought I had a pretty fast metabolism. Even before I started CICO I was on the sidelines of, "normal weight/overweight" on the BMI chart and I swear I was eating over 3k calories a day. I started doing CICO and set it to lose .5 pounds a week and I averaged over 1 pound a week for 16 weeks and I always thought it was because I had a faster than usual metabolism.

    Some people have a higher or lower BMR which is basically your 'metabolism'. Factors that influence this are lean muscle mass, height, age etc. So if you feel like you have a faster metabolism it may be you're young tall and lean.

    Let's look at 2 case studies:

    If you are MALE, 175cm, 95 kg, 25 yrs your BMR is about 2079 calories

    If you are FEMALE, 163cm, 60kg, 25 yrs your BMR is about 1414 calories.

    That's a difference of 665 calories. That's a lot more food you can eat.

    I don't believe this is correct. You may have misunderstood me. What I'm saying is, I found what calculators said was my BMR or TDEE and what I'm suppose to lose eating 1800 calories (sometimes more) a day and I have lost double more than I was suppose to. I feel I actually do have a fast metabolism than I took advantage of for too many years.

    Given all the factors that go into creating a calorie deficit, it's much more likely that your counts are off in the number of calories you're eating, your activity level, and/or your exercise calories than it is that your have a metabolic rate which deviates significantly than the general population.

    Entirely plausible that I'm off somewhere in my calculations.

    With all the issues I see on here with other people logging, weighing, measuring and how easy it is for me to accidentally lose twice as fast as I wanted to... Isn't that entirely plausible to say I MAY have a faster metabolism?

    I don't think we have enough information to make that determination. I can't even see your diary to check how well you log or if you weigh your food, I don't know what your exercise burns look like or how much of them you eat back, etc. Even without that information, I still think it's more likely your calculations are off than you have a significanty higher metabolic rate. Or maybe you have a tapeworm.

    Damnit... I probably have a tapeworm.

    Similar to a tapeworm, if you had an actual metabolic condition that made anywhere near the difference you're coming up with, you'd almost assuredly have other signs of it.
    For example, Lizzie Velasquez (https://en.wikipedia.org/wiki/Lizzie_Velásquez) has a genetic condition where she can't gain on a 5,000-8,000 calories a day. She's a 1 in 7 billion kind of metabolism though, and she has numerous other issues that demonstrate her metabolism.
    Off the top of my head, I'd say if you had a BMR that was actually around 3,000-4,000 calories, doing any kind of exercise with intensity would leave your body unbearably hot as you probably would go past the ability of a human body to remove heat.

    It's amazing she has taken her life situation and turned into a positive by speaking with other people about it.
  • senecarr
    senecarr Posts: 5,377 Member
    So I'm clear - There is no such thing as fast metabolism/ slow metabolism? I ask because I've always thought I had a pretty fast metabolism. Even before I started CICO I was on the sidelines of, "normal weight/overweight" on the BMI chart and I swear I was eating over 3k calories a day. I started doing CICO and set it to lose .5 pounds a week and I averaged over 1 pound a week for 16 weeks and I always thought it was because I had a faster than usual metabolism.

    Some people have a higher or lower BMR which is basically your 'metabolism'. Factors that influence this are lean muscle mass, height, age etc. So if you feel like you have a faster metabolism it may be you're young tall and lean.

    Let's look at 2 case studies:

    If you are MALE, 175cm, 95 kg, 25 yrs your BMR is about 2079 calories

    If you are FEMALE, 163cm, 60kg, 25 yrs your BMR is about 1414 calories.

    That's a difference of 665 calories. That's a lot more food you can eat.

    I don't believe this is correct. You may have misunderstood me. What I'm saying is, I found what calculators said was my BMR or TDEE and what I'm suppose to lose eating 1800 calories (sometimes more) a day and I have lost double more than I was suppose to. I feel I actually do have a fast metabolism than I took advantage of for too many years.

    Given all the factors that go into creating a calorie deficit, it's much more likely that your counts are off in the number of calories you're eating, your activity level, and/or your exercise calories than it is that your have a metabolic rate which deviates significantly than the general population.

    Entirely plausible that I'm off somewhere in my calculations.

    With all the issues I see on here with other people logging, weighing, measuring and how easy it is for me to accidentally lose twice as fast as I wanted to... Isn't that entirely plausible to say I MAY have a faster metabolism?

    I don't think we have enough information to make that determination. I can't even see your diary to check how well you log or if you weigh your food, I don't know what your exercise burns look like or how much of them you eat back, etc. Even without that information, I still think it's more likely your calculations are off than you have a significanty higher metabolic rate. Or maybe you have a tapeworm.
    Well, it would only be 250-ish above what the calculator told her. It was 1 pound per week when she wanted 0.5. That's still worlds more plausible than the constant "I'm eating like 800 calories and exercising 2 hours daily but not losing anything" posts.
    In terms of being off in logging and activity, that's extremely possible. For BMR, being 250 calories above the mean would still put her a bit high. If the average BMR is 1500 (just a complete guess on my part), with 2 deviations being a 10-16% difference (from examine.com link earlier in thread), you're looking at 240 calories, so that would place her in the top 2% of the population. That number becomes even more odd when you throw in she's a woman who doesn't appear particularly tall.
  • Werk2Eat
    Werk2Eat Posts: 114 Member
    I can say from personal experience that someone who weighs 200lbs and exercises and eats back there exercise calories and stays at the same deficit as someone who weights the same and eats at the same deficit but doesnt exercise will lose at a slower place. Keyword: lose and slower.
  • DeguelloTex
    DeguelloTex Posts: 6,652 Member
    edited September 2015
    Werk2Eat wrote: »
    I can say from personal experience that someone who weighs 200lbs and exercises and eats back there exercise calories and stays at the same deficit as someone who weights the same and eats at the same deficit but doesnt exercise will lose at a slower place. Keyword: lose and slower.
    Hard to imagine a scenario in which one person's 500 calorie deficit results in different loss than someone else's 500 calorie deficit. At least not a fictional scenario.

    Well, maybe if one is really fat and one is really lean so that the deficit is causing muscle loss instead of fat loss.

  • senecarr
    senecarr Posts: 5,377 Member
    Werk2Eat wrote: »
    I can say from personal experience that someone who weighs 200lbs and exercises and eats back there exercise calories and stays at the same deficit as someone who weights the same and eats at the same deficit but doesnt exercise will lose at a slower place. Keyword: lose and slower.
    Depends on how correct the exercise calories are, and if the exercise has been routine long enough to not cause water weight.
  • Werk2Eat
    Werk2Eat Posts: 114 Member
    Hard to imagine a scenario in which one person's 500 calorie deficit results in different loss than someone else's 500 calorie deficit. At least not a fictional scenario.

    Well, maybe if one is really fat and one is really lean so that the deficit is causing muscle loss instead of fat loss.

    In my senario, i had been 200lbs more then once and each time i got to 200 and decided to lose 50 pounds it got easier and took less time. I always kept the same deficit but increased my exercise as my cardio had improved as the years went by. Its pretty obvious exercise increases your metabolism and is why most very active people have high metabolisms and are usually skinny.

  • DeguelloTex
    DeguelloTex Posts: 6,652 Member
    If you increased cardio then you didn't have the same net deficit.
  • tincanonastring
    tincanonastring Posts: 3,944 Member
    Werk2Eat wrote: »
    Hard to imagine a scenario in which one person's 500 calorie deficit results in different loss than someone else's 500 calorie deficit. At least not a fictional scenario.

    Well, maybe if one is really fat and one is really lean so that the deficit is causing muscle loss instead of fat loss.

    In my senario, i had been 200lbs more then once and each time i got to 200 and decided to lose 50 pounds it got easier and took less time. I always kept the same deficit but increased my exercise as my cardio had improved as the years went by. Its pretty obvious exercise increases your metabolism and is why most very active people have high metabolisms and are usually skinny.

    Exercise has an inherent recovery period during which the body continues burning calories. This isn't normally factored into our calorie burns (it's just a pleasant side benefit), but that doesn't mean our metabolic rate has increased.
  • tincanonastring
    tincanonastring Posts: 3,944 Member
    If you increased cardio then you didn't have the same net deficit.

    If you ate back your calories you would. What Werk2Eat is seeing, if he was eating back exactly what his cardio burned, is the recovery burn.
  • lemurcat12
    lemurcat12 Posts: 30,886 Member
    edited September 2015
    tomatoey wrote: »
    lemurcat12 wrote: »
    But certainly I think food is the bigger part, but that's because I think that most humans don't have a natural stop mechanism when it comes to food


    This hasn't been my experience at all - I don't want to eat once I feel full, and I do feel full, once I hit my macros/calorie targets (and did long before I knew what they were, i.e. by eating intuitively. I leave stuff on my plate all the time, always have). My "natural stop mechanism" only fails when what I'm eating is chips. I think it might hard to reach satiety with some ratios or foods. But when I'm eating an even roughly "healthy" diet, I get full at a certain point and stop there.

    I don't mean to overstate it, but I think the intuitive eating idea is that people will eat the amount needed to avoid gaining--that they won't overeat. There's no real benefit to that evolutionarily, and I don't see any evidence that most people are calibrated that way, which is why in conditions of surplus, without natural restrictions on how much we eat (like cultural ones), the majority of people seem to become overweight, unless they impose the restrictions themselves.

    I'm not talking about eating after you feel full, but my idea here is that fullness often does not kick in until after you've consumed more than ideal calories.

    And obviously there are exceptions (even in the US something like 30% aren't overweight, and some portion of them seem to naturally stay thin without thinking about it much, especially when younger and more active), so maybe you are someone who does more naturally regulate your food under normal circumstances. The evidence seems to me that most humans aren't such people.

    I'm not -- and I'm not complaining about this, once you understand it it's not that tough to deal with. Even eating a healthy balanced diet I can easily overeat if I don't do things like eating only at certain periods of time and watching portion size.

    Oh, to elaborate on this a bit, it's not like you have to eat hugely excessive amounts to gain. Just eat an extra 100 calories a day and it adds up over time. I gained lots of weight (fast) by going from very active to sedentary and basically eating the same diet for some time, and it was a healthy diet.
  • lemurcat12
    lemurcat12 Posts: 30,886 Member
    Ok, so new question relating to metabolism. If it's true that metabolism has very little to do with weight loss / gain, why is it that older people seem to have a much harder time losing weight or getting in shape? Is this just another societal myth, or do they really find it more difficult due to a slowing down metabolism? Or are there other factors of which I'm unaware?

    A bigger factor beyond natural variations in metabolism (BMR) is likely activity, and older people commonly become less active and have a longer history of habits to overcome.

    That said, I lost weight in my early 30s and mid 40s and didn't find it tougher in my mid 40s.
  • DeguelloTex
    DeguelloTex Posts: 6,652 Member
    If you increased cardio then you didn't have the same net deficit.

    If you ate back your calories you would. What Werk2Eat is seeing, if he was eating back exactly what his cardio burned, is the recovery burn.
    If he ate back exactly the increased calories to keep a 500 net deficit in both scenarios then, again, it's still hard to imagine a meaningful difference in weight loss. Recovery burn, if you're talking after after burn, probably doesn't outstrip the error inherent in measuring eating and burning.

  • goldthistime
    goldthistime Posts: 3,214 Member
    lemurcat12 wrote: »
    tomatoey wrote: »
    lemurcat12 wrote: »
    But certainly I think food is the bigger part, but that's because I think that most humans don't have a natural stop mechanism when it comes to food



    hqdefault.jpg

    This hasn't been my experience at all - I don't want to eat once I feel full, and I do feel full, once I hit my macros/calorie targets (and did long before I knew what they were, i.e. by eating intuitively. I leave stuff on my plate all the time, always have). My "natural stop mechanism" only fails when what I'm eating is chips. I think it might hard to reach satiety with some ratios or foods. But when I'm eating an even roughly "healthy" diet, I get full at a certain point and stop there.

    I don't mean to overstate it, but I think the intuitive eating idea is that people will eat the amount needed to avoid gaining--that they won't overeat. There's no real benefit to that evolutionarily, and I don't see any evidence that most people are calibrated that way, which is why in conditions of surplus, without natural restrictions on how much we eat (like cultural ones), the majority of people seem to become overweight, unless they impose the restrictions themselves.

    I'm not talking about eating after you feel full, but my idea here is that fullness often does not kick in until after you've consumed more than idea calories.

    And obviously there are exceptions (even in the US something like 30% aren't overweight, and some portion of them seem to naturally stay thin without thinking about it much, especially when younger and more active), so maybe you are someone who does more naturally regulate your food under normal circumstances. The evidence seems to me that most humans aren't such people.

    I'm not -- and I'm not complaining about this, once you understand it it's not that tough to deal with. Even eating a healthy balanced diet I can easily overeat if I don't do things like eating only at certain periods of time and watching portion size.

    Personally, if I keep my sugars and starchy carbs on the low side I feel full at maintenance levels.

  • Werk2Eat
    Werk2Eat Posts: 114 Member
    If you increased cardio then you didn't have the same net deficit.

    If you read my initial post i had mentioned that i ate back the exercise calories. I included exercise on both diets but it got easier and faster to lose because i was able to exercise more as the second time around my cardio had got better. I still had the same deficit but had more exercise daily.

  • DeguelloTex
    DeguelloTex Posts: 6,652 Member
    Werk2Eat wrote: »
    If you increased cardio then you didn't have the same net deficit.

    If you read my initial post i had mentioned that i ate back the exercise calories. I included exercise on both diets but it got easier and faster to lose because i was able to exercise more as the second time around my cardio had got better. I still had the same deficit but had more exercise daily.
    Which, again, wouldn't meaningfully impact weight loss at a given, constant deficit.

  • tincanonastring
    tincanonastring Posts: 3,944 Member
    If you increased cardio then you didn't have the same net deficit.

    If you ate back your calories you would. What Werk2Eat is seeing, if he was eating back exactly what his cardio burned, is the recovery burn.
    If he ate back exactly the increased calories to keep a 500 net deficit in both scenarios then, again, it's still hard to imagine a meaningful difference in weight loss. Recovery burn, if you're talking after after burn, probably doesn't outstrip the error inherent in measuring eating and burning.

    Oh, I've no doubt that's the far more likely scenario, but I had moved on to a more hypothetical situation.