The myth of metabolism

myofibril

I think the myth is, in general, the belief that leaner individuals are that way because they have a faster metabolism than larger folks due to genetics or somatotypes.

Barring metabolic disorders, obese people tend to have quicker metabolisms than their slimmer counterparts:

See here: http://jn.nutrition.org/content/134/6/1412.long?related-urls=yes&legid=nutrition;134/6/1412

ETA: very good article by Tom Venuto discussing a "slow" metabolism here: www.burnthefat.com/slow-metabolism-problems.html

alexis831

Interesting post.

First of all, hormones can effect expenditure so I wouldn't go so far as to say that it's a "myth". But I would also add that people tend to use "metabolism" as a big excuse when either justifying their own inability to lean out OR when looking at another person's physique and pinning it on their "super high metabolism".

I read a post a few days ago where a friend of mine posted her pics and she eats what most people would call "junk food", and a few people immediately chimed in with ridiculous claims of "you must be lucky to have that metabolism" and "lets see you do that when you get older". They completely glossed over the fact that she isn't over-consuming calories. She's creating a deficit like the rest of us should be doing when trying to lean out.

Non Exercise Activity Thermogenesis is gives a very big contribution to TDEE, and in addition to this, I absolutely agree with the OP that in just about all cases, "you don't know how much that other person really eats".

Typically people who are overweight are over-estimating their deficit or under-estimating their food intake. Hardgainers typically over-estimate their food intake and simply don't eat as much as they think.

All of the above factors play a role in this.


So are different metabolisms a "myth"? Of course not. But it sure is a good excuse.

So true!!!

A_Shannigans

I think the myth is, in general, the belief that leaner individuals are that way because they have a faster metabolism than larger folks due to genetics or somatotypes.

Barring metabolic disorders, obese people tend to have quicker metabolisms than their slimmer counterparts:

See here: http://jn.nutrition.org/content/134/6/1412.long?related-urls=yes&legid=nutrition;134/6/1412

ETA: very good article by Tom Venuto discussing a "slow" metabolism here: www.burnthefat.com/slow-metabolism-problems.html

I wonder if he can explain the skinny person who eats more and is not any more active than their not so skinny friend. It happens something causes it. Maybe I don't understand metabolism. My understanding is if you can eat more calories without gaining weight you would have a higher metabolism than the person who eats less and gains more but is just as active.

Sidesteal

Read this: http://body-improvements.com/resources/eat/#metabolism

The fact is, metabolic rate does not vary drastically between matched populations. But I suppose that depends on your definition of drastically. I'd say that it certainly can vary meaningfully... in the tune of 30% differences between the slowest and fastest.

You better believe that someone who's 15% above average is going to have an easier time controlling weight than someone who's 15% below the average.

More interestingly is the concept of spontaneous physical activity or non-exercise activity thermogenesis. Some people are high responders while others are not. What I mean is, some people, when faced with a surplus, will automatically expend more energy through activity to defend against the surplus. This activity can be mostly unconscious, such as fidgeting and such. This can account for 600+ calories worth of expenditure per day.

Think about that for a second.

Chances are, the people you know who can't gain weight no matter what they eat aren't working with super fast resting metabolic rates. Rather, it's more likely dealing with the fact that they have very high SPAs or NEATs in the face of overfeeding.

On the flipside, some people, in the face of a calorie shortage, overcompensate their SPA/NEAT by unconsciously expending substantially less energy via activity, which is likely one of the primary culprits making lasting weight loss so challenging.

Bumping this and bolding the site. To anyone reading this that isn't familiar with Steve Troutman's work, check him out. This guy has a great pile of free articles on his site and you won't find any broscience here. Solid info.

stormieweather

Something I noticed is that when I was younger (slim and never gained a pound no matter what I ate), I fidgeted a lot. I mean, like shifting foot to foot, jiggling foot, tapping feet and hands, unconsiously moving to songs in my head (aka SPA/NEAT, as described by Steve Troutman). However, over the years, I've stopped doing this. I used to think it was due to becoming more centered and calm :laugh: , but I think now that it's metabolically related. And at the same time as my body motion decreased, my weight increased (along with my age).

klmh128

"One of the few studies ever to have scrupulously monitored exercise, food intake and metabolic rates found that volunteers’ basal metabolic rates dropped as they lost weight, even though they exercised every day. As a result, although they were burning up to 500 calories during an exercise session, their total daily caloric burn was lower than it would have been had their metabolism remained unchanged, and they lost less weight than had been expected."


http://well.blogs.nytimes.com/2012/08/01/dieting-vs-exercise-for-weight-loss/?src=me&ref=general

Metabolism is not a myth, but the exact way it works in combination with diet and exercise is still being researched. I think it really all comes back to what and how much you eat more than fast or slow metabolism. Of course, that statement is barring anyone with a metabolic disorder requiring medication - special circumstances.

stroutman81

I wonder if he can explain the skinny person who eats more and is not any more active than their not so skinny friend.

That was sort of the point in my previous post. You can't say, "he's not any more active than... "

You can say they eat the same number of calories. You can say they have the same sedentary jobs. You can say they follow the same exercise program. But that's not accounting for SPA/NEAT, which as noted, can play massive roles in total energy expenditure.

myofibril

I wonder if he can explain the skinny person who eats more and is not any more active than their not so skinny friend. It happens something causes it.

Differences in metabolic rates do vary amongst individuals but it is not as great as people believe in many instances - about 3% - 8% were the figures given in the article.

I suspect if you got the skinny and not so skinny individual into a metabolic ward you would probably find the skinny friend ate less and /or had a higher level of physical activity. However, physical activity doesn't only mean planned physical exercise like jogging or going to the gym.

It can also be NEAT / SPA as the posts by Sidesteal reference. Some people just can't keep still for the life of them. What does that do? Burn calories. It's an aggregation of small benefits.

The reason most people put on weight as they get older isn't really about "metabolism" as such or even loss of muscle mass (although that does play a small part.)

It's because people generally become more sedentary and eat more as they get older.

stroutman81

I wonder if he can explain the skinny person who eats more and is not any more active than their not so skinny friend. It happens something causes it.

Differences in metabolic rates do vary amongst individuals but it is not as great as people believe in many instances - about 3% - 8% were the figures given in the article.

I suspect if you got the skinny and not so skinny individual into a metabolic ward you would probably find the skinny friend ate less and /or had a higher level of physical activity. However, physical activity doesn't only mean planned physical exercise like jogging or going to the gym.

It can also be NEAT / SPA as the posts by Sidesteal reference. Some people just can't keep still for the life of them. What does that do? Burn calories. It's an aggregation of small benefits.

The reason most people put on weight as they get older isn't really about "metabolism" as such or even loss of muscle mass (although that does play a small part.)

It's because people generally become more sedentary and eat more as they get older.

Exactly.

And it's worth noting that there are other papers which show wider disparities between metabolic rates across matched populations, but even there you're talking +/- 15%.

aqm22

I wonder if he can explain the skinny person who eats more and is not any more active than their not so skinny friend. It happens something causes it.

Differences in metabolic rates do vary amongst individuals but it is not as great as people believe in many instances - about 3% - 8% were the figures given in the article.

I suspect if you got the skinny and not so skinny individual into a metabolic ward you would probably find the skinny friend ate less and /or had a higher level of physical activity. However, physical activity doesn't only mean planned physical exercise like jogging or going to the gym.

It can also be NEAT / SPA as the posts by Sidesteal reference. Some people just can't keep still for the life of them. What does that do? Burn calories. It's an aggregation of small benefits.

The reason most people put on weight as they get older isn't really about "metabolism" as such or even loss of muscle mass (although that does play a small part.)

It's because people generally become more sedentary and eat more as they get older.

I agree that people become much more sedentary when they get older (desk jobs, driving, etc). I don't think it's so much that they eat more. I think it's a lot more that they eat "more than they need". Meaning, they probably eat about the same maybe a little bit more depending on their lifestyle, but people probably don't need to eat as much as they were younger and more, however little, active.

Sitting on your butt and having the same eating habits can pack on weight fast. That's my experience.

EvgeniZyntx

Suggest the OP look into hyperthyroidism, hypothyroidism, metabolic syndrome, insulin and a variety of other proofs on metabolic variability.

Pubmed is just a click away.

http://www.ncbi.nlm.nih.gov/pubmed?term=basal metabolic variability

TMcSter

Great topic!

abbylg1983

I can't say it's a myth, because I am not qualified to make that statement, having done little to no research on the topic. I do think, however, just based on who I know, that it is greatly exaggerated. It's easy to shrug off a skinny (or reasonably thin) person eating junk food as a genetic lottery winner, but I would say for the most part (of course there are exceptions to every rule) if someone has a better body than me, she probably eats better than I do and exercises more. Of course everyone knows some freak of nature they swear up and down eats 3,000 calories of crap all day while also spending all day watching TV or playing video games. I don't personally, but I've heard enough people say it that they must be out there.

What is more interesting to me than metabolism is where someone stores fat. My good friend for example, is around 5'8, and while I never knew her weight, she was skinny. Two years ago she started gaining weight, and since I met her, has probably put on a good 20 pounds. She is still thin, but no one would call her skinny anymore. Still, she has a completely flat stomach. She just can't gain fat there. My BMI is probably less than hers (and I have more muscle) and I wear a smaller size, yet I still have a stomach pooch and she does not. Lucky *****.

myofibril

I agree that people become much more sedentary when they get older (desk jobs, driving, etc). I don't think it's so much that they eat more. I think it's a lot more that they eat "more than they need". Meaning, they probably eat about the same maybe a little bit more depending on their lifestyle, but people probably don't need to eat as much as they were younger and more, however little, active.

Sitting on your butt and having the same eating habits can pack on weight fast. That's my experience.

Yep, very good point.

Having said that it's not only "average" people this happens to but also top class athletes. If you are into cycling you will know what happened to Eddy Merckx for a while after he stopped racing but kept eating like he still was...I am sure many people would look at him in his prime and if they didn't know him would assume he had a quick metabolism!

mkstirp

There is more to it than just your metabolic rate. There is most likely a lot of variation in efficiencies too. No one's gut absorbs every calorie. Absorption rates can be affected by what you eat (ie fiber), how much surface area of intestines, and enzymes and hormones. Additionally, fat adsorption is a whole separate process. Most of the fat we eat goes right to storage to be used later when the body runs out of available carbs. The body only needs a bit of fat in the mix to create the energy needed.

blair_bear

Interesting post.

First of all, hormones can effect expenditure so I wouldn't go so far as to say that it's a "myth". But I would also add that people tend to use "metabolism" as a big excuse when either justifying their own inability to lean out OR when looking at another person's physique and pinning it on their "super high metabolism".

This^^ I had Oocytes cultivated and frozen a few years ago in the case of my husband and I wanting to find a surrogate at some point. The hormones they inject you with caused a complete 180 in my body, especially my metabolism. Things were instantly different for me and I had to re-learn my caloric intake/output, etc. I don't think it's a "myth" just based on that personal experience.

GaidenJade

Sorry. I have to respectfully disagree. I can give you two examples. My best friend. She is my height, only two years older than I am and she eats candy, cookies and out eats me at every single turn. I have watched her down a dozen of chocolate chip cookies without blinking. And she is stick thin! She never has an issue with weight, she doesn't exercise, she eats like this every day of her life! She has admitted to having a chocolate addiction.

My second example? My sister in law. She has gained a little weight since marrying my brother, because my family is big on eating crap. However she is still tiny.

Genetics plays a HUGE role in how a person gains weight. The Thyroid, regulates the metabolism, so if your thyroid doesn't work as well as the next persons, then you will obviously have a problem losing weight, or will gain more quickly than another.

Goal_Line

Sure on an individual basis SOME people may have metabolism issues.

But I firmly by and large across broad populations thinner people have different behaviors than fat people.

How do you explain the increase in obesity in America over the past generation? Did we all go through a genetic transformation which impaired our metabolism compared to our parents or grandparents? OR Is our lifestyle different?

I vote lifestyle. For all but a few of us, if we change behaviors we'll get different results.

EvgeniZyntx

And it's worth noting that there are other papers which show wider disparities between metabolic rates across matched populations, but even there you're talking +/- 15%.

+15%? That's 60 pizzas a year for me. It certainly would be visible if I was able to eat that.

ModoVincere

And it's worth noting that there are other papers which show wider disparities between metabolic rates across matched populations, but even there you're talking +/- 15%.

+15%? That's 60 pizzas a year for me. It certainly would be visible if I was able to eat that.

That' my thought....15% of 2000 kCals/day would be 300kCals. That's a bit over 1/2 pound a week gain or loss.

A_Shannigans

I can't say it's a myth, because I am not qualified to make that statement, having done little to no research on the topic. I do think, however, just based on who I know, that it is greatly exaggerated. It's easy to shrug off a skinny (or reasonably thin) person eating junk food as a genetic lottery winner, but I would say for the most part (of course there are exceptions to every rule) if someone has a better body than me, she probably eats better than I do and exercises more. Of course everyone knows some freak of nature they swear up and down eats 3,000 calories of crap all day while also spending all day watching TV or playing video games. I don't personally, but I've heard enough people say it that they must be out there.

What is more interesting to me than metabolism is where someone stores fat. My good friend for example, is around 5'8, and while I never knew her weight, she was skinny. Two years ago she started gaining weight, and since I met her, has probably put on a good 20 pounds. She is still thin, but no one would call her skinny anymore. Still, she has a completely flat stomach. She just can't gain fat there. My BMI is probably less than hers (and I have more muscle) and I wear a smaller size, yet I still have a stomach pooch and she does not. Lucky *****.

I would agree that people like me are definitely not the norm and that in most cases physical activity or diet are behind the differences...but not always.

I do not have trouble gaining at in my tummy now that I can gain though.

A_Shannigans

I wonder if he can explain the skinny person who eats more and is not any more active than their not so skinny friend. It happens something causes it.

Differences in metabolic rates do vary amongst individuals but it is not as great as people believe in many instances - about 3% - 8% were the figures given in the article.

I suspect if you got the skinny and not so skinny individual into a metabolic ward you would probably find the skinny friend ate less and /or had a higher level of physical activity. However, physical activity doesn't only mean planned physical exercise like jogging or going to the gym.

It can also be NEAT / SPA as the posts by Sidesteal reference. Some people just can't keep still for the life of them. What does that do? Burn calories. It's an aggregation of small benefits.

The reason most people put on weight as they get older isn't really about "metabolism" as such or even loss of muscle mass (although that does play a small part.)

It's because people generally become more sedentary and eat more as they get older.

I can't say I was not even slightly more active then my heftier friends but I can say the difference in our activity was minimal enough that my calorie intake should have more than made up for it.

I can tell you when I started to put on the weight I was just as active as I had been for the previous 5 years at least. Although when I switched to an office job the weight gain accelerated which was to be expected.

What I'm saying is this paper over simplifies as does the whole metabolism myth theory. It implies that we all will drop or put on weight at near identical levels diet and exercise being equal. No two humans are that much alike. There are so many variables OTHER than diet and exercise I don't see how that can be qualified.

Again perhaps it's not cause by metabolic weight but some people are able to keep weight off more effortlessly than others. Are they common? No but they do exist.

HealthyBodySickMind

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