Metabolism
Aaron_K123
Posts: 7,122 Member
Got a chuckle out of this one, thought I'd share.
http://xkcd.com/1744/
I will have to remember this one for next time someone says "you must have a fast metabolism".
http://xkcd.com/1744/
I will have to remember this one for next time someone says "you must have a fast metabolism".
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Replies
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That's me in a nutshell!
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Just saw that and was going to post it, but you beat me to the punch!0
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My mom told me Saturday she was blessed with a fast metabolism. I told her that no, she is extremely active. Normally women in their late 70s do not paint their houses. GET OFF OF THE LADDER, MOM!15
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kshama2001 wrote: »My mom told me Saturday she was blessed with a fast metabolism. I told her that no, she is extremely active. Normally women in their late 70s do not paint their houses. GET OFF OF THE LADDER, MOM!
This is SO MUCH my mom, too. She's over 70, she works at Home Depot in flooring lifting boxes of tile all day so she doesn't get bored.1 -
It made me so happy to see this was a post I'd seen on my favorite "tough love" sub earlier.0
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From the Academy of Nutrition and Dietetics:
Why can one person eat like a growing teenager and not gain a pound, while another person's every indulgence shows up on the scale? Chalk it up to individual differences in metabolism, muscle mass and physical activity. Metabolism is the process by which our bodies convert what we eat into the energy we need to survive and function. Tweet this It powers everything from breathing to blinking. A fast metabolism is like a hot furnace that burns through fuel (calories) quickly. A slow metabolism needs less fuel to keep a body running.
Are you denying that there is such a thing as a fast metabolism and a slow metabolism?
Did you miss the muscle mass and physical activity part?
Individual differences in BMR alone tend to be within 200 calories or less. Think about that...fast and slow basal metabolic rate with disparities of less than 200 calories for fully grown adults. Add in muscle mass and physical activity, and boom, a medical miracle appears! A person who runs marathons can eat far more than a person who sits at a desk all day and doesn't exercise!
I used to blame my health conditions and metabolism. And then I bought a food scale and a heart rate monitor.... 98lbs down and counting. Your source is being quite hyperbolic and unscientific as well.6 -
Your metabolism generally slows as you get older. Some slow quicker than others, and others don't slow down at all (I doubt any speed up).
...due to decreased muscle mass and less activity.
ETA: In fact, those who become more active as they age or get in the gym and start building muscle (more difficult but not impossible later in life) can indeed see an increase in metabolism.6 -
Carlos_421 wrote: »
Yup, I wish I had the muscle mass and activity level I had in my 20s.1 -
From the Academy of Nutrition and Dietetics:
Why can one person eat like a growing teenager and not gain a pound, while another person's every indulgence shows up on the scale? Chalk it up to individual differences in metabolism, muscle mass and physical activity. Metabolism is the process by which our bodies convert what we eat into the energy we need to survive and function. Tweet this It powers everything from breathing to blinking. A fast metabolism is like a hot furnace that burns through fuel (calories) quickly. A slow metabolism needs less fuel to keep a body running.
Are you denying that there is such a thing as a fast metabolism and a slow metabolism?
There's one difference between your body and a furnace.
A furnace can just put off a lot of heat (energy) and let it out into the atmosphere. You can't. Every calorie you burn is metabolized into energy as that energy is utilized. Your body doesn't just burn up a bunch of calories "cuz fast metabolism" and release it through flatulence.
Calories are burned to fuel activity (both internal and external). Maintenance of muscle mass uses some energy so more muscle means a higher metabolism. Moving uses energy so being twitchy, nervous and fidgety means a higher metabolism.
Other than factors like that, there is no such thing as some people just having a higher base setting.
Yes, some people burn more calories than others (have a higher metabolism) but it's because they have more muscle and/or they move more.2 -
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Carlos_421 wrote: »From the Academy of Nutrition and Dietetics:
Why can one person eat like a growing teenager and not gain a pound, while another person's every indulgence shows up on the scale? Chalk it up to individual differences in metabolism, muscle mass and physical activity. Metabolism is the process by which our bodies convert what we eat into the energy we need to survive and function. Tweet this It powers everything from breathing to blinking. A fast metabolism is like a hot furnace that burns through fuel (calories) quickly. A slow metabolism needs less fuel to keep a body running.
Are you denying that there is such a thing as a fast metabolism and a slow metabolism?
There's one difference between your body and a furnace.
A furnace can just put off a lot of heat (energy) and let it out into the atmosphere. You can't. Every calorie you burn is metabolized into energy as that energy is utilized. Your body doesn't just burn up a bunch of calories "cuz fast metabolism" and release it through flatulence.
Calories are burned to fuel activity (both internal and external). Maintenance of muscle mass uses some energy so more muscle means a higher metabolism. Moving uses energy so being twitchy, nervous and fidgety means a higher metabolism.
Other than factors like that, there is no such thing as some people just having a higher base setting.
Yes, some people burn more calories than others (have a higher metabolism) but it's because they have more muscle and/or they move more.
Well, no, not quite.
There is, indeed, going to be a range of BMR/RMR values for different individuals with the same relevant statistics. If you put me next to another woman born on the same exact day, with the same height, same weight, and same lean/fat mass, it would not be a guarantee that our BMR/RMR would be exactly the same. The range is going to be a bell curve, of course - the vast majority of individuals are going to be within a relatively small margin of a couple hundred calories - but it's technically possible for people to have a BMR/RMR that is several hundred calories above or below that mean.
That said, the people who have noticeably higher or lower BMR/RMRs are absolutely the exception rather than the rule. Most of the time people who are anecdotally considered to have "fast" metabolisms do just move a lot more (and possibly eat less), even if they and/or the people around them don't really realize it.2 -
Carlos_421 wrote: »From the Academy of Nutrition and Dietetics:
Why can one person eat like a growing teenager and not gain a pound, while another person's every indulgence shows up on the scale? Chalk it up to individual differences in metabolism, muscle mass and physical activity. Metabolism is the process by which our bodies convert what we eat into the energy we need to survive and function. Tweet this It powers everything from breathing to blinking. A fast metabolism is like a hot furnace that burns through fuel (calories) quickly. A slow metabolism needs less fuel to keep a body running.
Are you denying that there is such a thing as a fast metabolism and a slow metabolism?
Yes, some people burn more calories than others (have a higher metabolism) but it's because they have more muscle and/or they move more.
I don't get it. It's the string beans that have the higher metabolism, that's why they tend to be string beans. Of course I am not saying that all string beans have fast metabolisms.
Nope. I was obese for decades, and it turns out that my NEAT is higher than the calculators predict for my daily activity level/size/age/etc. You can out-eat a so-called "fast metabolism" just like you can out-eat most rational levels of exercise. We're only talking a few hundred calories here, tops.2 -
Some people are also less efficient at absorbing energy / digesting food than others. These malabsorption issues can lead to what appears to be a "fast metabolism" when they're just not too great at extracting energy from food in the first place. On the other hand, it's been demonstrated some people are better at extracting energy from food. This is of particular interest in the gut microbe research going on, as there are microbiota that are really REALLY good at harvesting and freeing up energy for our use. This is a relatively new area of research with a small number of laboratories investigating it, so should be taken with (liberally applied) a grain of salt, but it is worth keeping in mind. This is not to negate CI/CO in the least, but it should be pointed out that per gram of equivalent food, individuals have varying ability to absorb, and with.
While 68% of the population exists within 1 standard deviation of the mean (+ or - 160 calories, a spread of 320!), and 95% within 2 standard deviations (+ or - 320 calories, a spread of 640), odds are very good you know someone outside the top and outside the bottom. And even within that 1st standard deviation, that 320 calories can SEEM like a lot. The 640 spread possible within 2 standard deviations is pretty darned significant, it is equivalent to a quite large meal a day extra. So yes, there are a fair number of people who can eat a good deal more than a fair number of other people and not gain weight.
CI/CO works for everyone, but not everyone has an identical physiological system. It's life, it's not fair, and while it feels nice to feel sorry for oneself if stuck on the lower end of the spectrum (like in the comic linked), it does no real good. It just means you have to work a little harder at maintaining homeostasis in a calorie-rich environment. And (sadly for me) eat a few less cookies.- Donahoo, William T., James A. Levine, and Edward L. Melanson. "Variability in energy expenditure and its components." Current Opinion in Clinical Nutrition & Metabolic Care 7.6 (2004): 599-605.
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Here are a few relevant articles regarding gut microbiota and metabolic effects.- Turnbaugh, Peter J., et al. "An obesity-associated gut microbiome with increased capacity for energy harvest." nature 444.7122 (2006): 1027-131.
- Turnbaugh, Peter J., and Jeffrey I. Gordon. "The core gut microbiome, energy balance and obesity." The Journal of physiology 587.17 (2009): 4153-4158.
- Bajzer, Matej, and Randy J. Seeley. "Physiology: obesity and gut flora." Nature 444.7122 (2006): 1009-1010.
- Vrieze A, Holleman F, Zoetendal EG, De Vos WM, Hoekstra JB, Nieuwdorp M. The environment within: how gut microbiota may influence metabolism and body composition. Diabetologia. 2010 Apr 1;53(4):606-13.
- Moreno-Indias, Isabel, et al. "Impact of the gut microbiota on the development of obesity and type 2 diabetes mellitus." Recent Discoveries in Evolutionary and Genomic Microbiology (2015): 57.
- Nieuwdorp, Max, et al. "Role of the microbiome in energy regulation and metabolism." Gastroenterology 146.6 (2014): 1525-1533.
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Your metabolism generally slows as you get older. Some slow quicker than others, and others don't slow down at all (I doubt any speed up).
I started weight lifting at 47
I also became far more active generally
And worked out 3 times a week minimum
Before I was a couch potato
I used to gain on 2000 calls, now I lose at less than 2400
Did my BMR rise or drop? My TDEE rose significantly, I'm pretty sure my BMR did marginally
I have greater muscle mass and am more active at 49 than 25
I have to eat more than my Fitbit step counting and exercise logging would suggest (unless I set my Fitbit to 30 years younger and 2" taller)4 -
They are string beans because they eat less and/or are more active. Ever notice that most of those string beans tend to be very energetic, high strung people?Carlos_421 wrote: »From the Academy of Nutrition and Dietetics:
Why can one person eat like a growing teenager and not gain a pound, while another person's every indulgence shows up on the scale? Chalk it up to individual differences in metabolism, muscle mass and physical activity. Metabolism is the process by which our bodies convert what we eat into the energy we need to survive and function. Tweet this It powers everything from breathing to blinking. A fast metabolism is like a hot furnace that burns through fuel (calories) quickly. A slow metabolism needs less fuel to keep a body running.
Are you denying that there is such a thing as a fast metabolism and a slow metabolism?
Yes, some people burn more calories than others (have a higher metabolism) but it's because they have more muscle and/or they move more.
I don't get it. It's the string beans that have the higher metabolism, that's why they tend to be string beans. Of course I am not saying that all string beans have fast metabolisms.Carlos_421 wrote: »From the Academy of Nutrition and Dietetics:
Why can one person eat like a growing teenager and not gain a pound, while another person's every indulgence shows up on the scale? Chalk it up to individual differences in metabolism, muscle mass and physical activity. Metabolism is the process by which our bodies convert what we eat into the energy we need to survive and function. Tweet this It powers everything from breathing to blinking. A fast metabolism is like a hot furnace that burns through fuel (calories) quickly. A slow metabolism needs less fuel to keep a body running.
Are you denying that there is such a thing as a fast metabolism and a slow metabolism?
There's one difference between your body and a furnace.
A furnace can just put off a lot of heat (energy) and let it out into the atmosphere. You can't. Every calorie you burn is metabolized into energy as that energy is utilized. Your body doesn't just burn up a bunch of calories "cuz fast metabolism" and release it through flatulence.
Calories are burned to fuel activity (both internal and external). Maintenance of muscle mass uses some energy so more muscle means a higher metabolism. Moving uses energy so being twitchy, nervous and fidgety means a higher metabolism.
Other than factors like that, there is no such thing as some people just having a higher base setting.
Yes, some people burn more calories than others (have a higher metabolism) but it's because they have more muscle and/or they move more.
Well, no, not quite.
There is, indeed, going to be a range of BMR/RMR values for different individuals with the same relevant statistics. If you put me next to another woman born on the same exact day, with the same height, same weight, and same lean/fat mass, it would not be a guarantee that our BMR/RMR would be exactly the same. The range is going to be a bell curve, of course - the vast majority of individuals are going to be within a relatively small margin of a couple hundred calories - but it's technically possible for people to have a BMR/RMR that is several hundred calories above or below that mean.
That said, the people who have noticeably higher or lower BMR/RMRs are absolutely the exception rather than the rule. Most of the time people who are anecdotally considered to have "fast" metabolisms do just move a lot more (and possibly eat less), even if they and/or the people around them don't really realize it.
Right, I don't contest that. But the differences in BMR in this example would be due to differences in bodily function (faster heartbeat, etc.) and not just some arbitrary metabolic rate dictated by genetics.
And of course, there is the absorption issue tomteboda mentioned above.3 -
Carlos_421 wrote: »
They are string beans because they eat less and/or are more active. Ever notice that most of those string beans tend to be very energetic, high strung people?Carlos_421 wrote: »From the Academy of Nutrition and Dietetics:
Why can one person eat like a growing teenager and not gain a pound, while another person's every indulgence shows up on the scale? Chalk it up to individual differences in metabolism, muscle mass and physical activity. Metabolism is the process by which our bodies convert what we eat into the energy we need to survive and function. Tweet this It powers everything from breathing to blinking. A fast metabolism is like a hot furnace that burns through fuel (calories) quickly. A slow metabolism needs less fuel to keep a body running.
Are you denying that there is such a thing as a fast metabolism and a slow metabolism?
Yes, some people burn more calories than others (have a higher metabolism) but it's because they have more muscle and/or they move more.
I don't get it. It's the string beans that have the higher metabolism, that's why they tend to be string beans. Of course I am not saying that all string beans have fast metabolisms.Carlos_421 wrote: »From the Academy of Nutrition and Dietetics:
Why can one person eat like a growing teenager and not gain a pound, while another person's every indulgence shows up on the scale? Chalk it up to individual differences in metabolism, muscle mass and physical activity. Metabolism is the process by which our bodies convert what we eat into the energy we need to survive and function. Tweet this It powers everything from breathing to blinking. A fast metabolism is like a hot furnace that burns through fuel (calories) quickly. A slow metabolism needs less fuel to keep a body running.
Are you denying that there is such a thing as a fast metabolism and a slow metabolism?
There's one difference between your body and a furnace.
A furnace can just put off a lot of heat (energy) and let it out into the atmosphere. You can't. Every calorie you burn is metabolized into energy as that energy is utilized. Your body doesn't just burn up a bunch of calories "cuz fast metabolism" and release it through flatulence.
Calories are burned to fuel activity (both internal and external). Maintenance of muscle mass uses some energy so more muscle means a higher metabolism. Moving uses energy so being twitchy, nervous and fidgety means a higher metabolism.
Other than factors like that, there is no such thing as some people just having a higher base setting.
Yes, some people burn more calories than others (have a higher metabolism) but it's because they have more muscle and/or they move more.
Well, no, not quite.
There is, indeed, going to be a range of BMR/RMR values for different individuals with the same relevant statistics. If you put me next to another woman born on the same exact day, with the same height, same weight, and same lean/fat mass, it would not be a guarantee that our BMR/RMR would be exactly the same. The range is going to be a bell curve, of course - the vast majority of individuals are going to be within a relatively small margin of a couple hundred calories - but it's technically possible for people to have a BMR/RMR that is several hundred calories above or below that mean.
That said, the people who have noticeably higher or lower BMR/RMRs are absolutely the exception rather than the rule. Most of the time people who are anecdotally considered to have "fast" metabolisms do just move a lot more (and possibly eat less), even if they and/or the people around them don't really realize it.
Right, I don't contest that. But the differences in BMR in this example would be due to differences in bodily function (faster heartbeat, etc.) and not just some arbitrary metabolic rate dictated by genetics.
And of course, there is the absorption issue tomteboda mentioned above.
A higher resting heart rate is not necessarily an indication of a higher BMR/RMR.
Of course differences in BMR/RMR are due to differences in bodily function. But, what causes those differences?
Lean body mass vs fat mass is a part of BMR/RMR; you can increase your BMR/RMR by increasing your lean body mass but it's really a very very small difference, 5 or 6 calories per day per pound of muscle. Previous history with diet and exercise may impact an individual's BMR/RMR at a point in time, though scientific research still doesn't quite agree on how significant that impact is. And an individual may have a hormonal imbalance impacting energy consumption (hypothyroidism, for example) that can be corrected through medicine. Other than that...seems like it's pretty darn arbitrary and probably in large part genetic, though environmental factors I'm sure come into play to some degree. My best knowledge is that there are no scientific studies that have identified any further factors causing variance in BMR/RMR.
I'll give you an example. Depending on the RMR calculation you use, my RMR (as measured several times by indirect calorimetry in a medical setting) is approximately 500 calories per day less than the mean for someone my sex/age/weight/height/lean body mass, which puts me outside even the 2nd standard deviation. Clearly my body does function very differently from most people's. But why? FFM has already been taken into account, I have no identifiable/treatable hormonal imbalances or other medical issues, I haven't recently lost a large amount of weight. Maybe it's genetics, maybe it's all the lead paint chips I ate as a kid, who knows. But something absolutely is arbitrarily directing my body to use less energy than what's typical.0 -
Carlos_421 wrote: »
They are string beans because they eat less and/or are more active. Ever notice that most of those string beans tend to be very energetic, high strung people?Carlos_421 wrote: »From the Academy of Nutrition and Dietetics:
Why can one person eat like a growing teenager and not gain a pound, while another person's every indulgence shows up on the scale? Chalk it up to individual differences in metabolism, muscle mass and physical activity. Metabolism is the process by which our bodies convert what we eat into the energy we need to survive and function. Tweet this It powers everything from breathing to blinking. A fast metabolism is like a hot furnace that burns through fuel (calories) quickly. A slow metabolism needs less fuel to keep a body running.
Are you denying that there is such a thing as a fast metabolism and a slow metabolism?
Yes, some people burn more calories than others (have a higher metabolism) but it's because they have more muscle and/or they move more.
I don't get it. It's the string beans that have the higher metabolism, that's why they tend to be string beans. Of course I am not saying that all string beans have fast metabolisms.Carlos_421 wrote: »From the Academy of Nutrition and Dietetics:
Why can one person eat like a growing teenager and not gain a pound, while another person's every indulgence shows up on the scale? Chalk it up to individual differences in metabolism, muscle mass and physical activity. Metabolism is the process by which our bodies convert what we eat into the energy we need to survive and function. Tweet this It powers everything from breathing to blinking. A fast metabolism is like a hot furnace that burns through fuel (calories) quickly. A slow metabolism needs less fuel to keep a body running.
Are you denying that there is such a thing as a fast metabolism and a slow metabolism?
There's one difference between your body and a furnace.
A furnace can just put off a lot of heat (energy) and let it out into the atmosphere. You can't. Every calorie you burn is metabolized into energy as that energy is utilized. Your body doesn't just burn up a bunch of calories "cuz fast metabolism" and release it through flatulence.
Calories are burned to fuel activity (both internal and external). Maintenance of muscle mass uses some energy so more muscle means a higher metabolism. Moving uses energy so being twitchy, nervous and fidgety means a higher metabolism.
Other than factors like that, there is no such thing as some people just having a higher base setting.
Yes, some people burn more calories than others (have a higher metabolism) but it's because they have more muscle and/or they move more.
Well, no, not quite.
There is, indeed, going to be a range of BMR/RMR values for different individuals with the same relevant statistics. If you put me next to another woman born on the same exact day, with the same height, same weight, and same lean/fat mass, it would not be a guarantee that our BMR/RMR would be exactly the same. The range is going to be a bell curve, of course - the vast majority of individuals are going to be within a relatively small margin of a couple hundred calories - but it's technically possible for people to have a BMR/RMR that is several hundred calories above or below that mean.
That said, the people who have noticeably higher or lower BMR/RMRs are absolutely the exception rather than the rule. Most of the time people who are anecdotally considered to have "fast" metabolisms do just move a lot more (and possibly eat less), even if they and/or the people around them don't really realize it.
Right, I don't contest that. But the differences in BMR in this example would be due to differences in bodily function (faster heartbeat, etc.) and not just some arbitrary metabolic rate dictated by genetics.
And of course, there is the absorption issue tomteboda mentioned above.
A higher resting heart rate is not necessarily an indication of a higher BMR/RMR.
I wasn't saying that it was. I just offered it up as an example of a possible factor as a faster heartbeat burns more calories than a slower hearbeat.0 -
Your metabolism generally slows as you get older. Some slow quicker than others, and others don't slow down at all (I doubt any speed up).
No...just no...
The slow down in marginal and in most cases undetectable. As others have already stated this is due to decreased activity and loss of muscle mass.0
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