The myth of metabolism

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.

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.

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.

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.

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".

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.

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.