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AspiringRationalist comments on What false beliefs have you held and why were you wrong? - Less Wrong Discussion

28 Post author: Punoxysm 16 October 2014 05:58PM

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Comment author: AspiringRationalist 20 October 2014 02:55:18AM 2 points [-]

Do you have a source for the claim that fat people don't generally have slow metabolisms?

Comment author: brazil84 20 October 2014 01:33:14PM 0 points [-]

Do you have a source for the claim that fat people don't generally have slow metabolisms?

I assume you mean some kind of formal reference as opposed to common sense arguments or general observations. If so, are you seriously skeptical of the claim? If the answer is "yes," then I will try to dig something up.

Comment author: Lumifer 20 October 2014 05:56:07PM 2 points [-]

If so, are you seriously skeptical of the claim?

I am sceptical of that claim, too.

I don't expect all fat people to have slow metabolisms, but I expect slow metabolism to be more prevalent among fat people as compared to thin people.

For example, there is a correlation between people's metabolism slowing down as they age and people gaining weight as they age (we're talking about the progression from, say, the 20s into the middle age, not old age). I am not ready to pronounce it a causal relationship, but the correlation is there.

Comment author: brazil84 25 October 2014 03:50:00PM 4 points [-]

I don't expect all fat people to have slow metabolisms, but I expect slow metabolism to be more prevalent among fat people as compared to thin people.

That's not quite the claim I was addressing - the claim is that generally speaking, obesity is the result of having a slow metabolism. But anyway, I was able to dig up some evidence:

First, a video which is obviously not a scientific study but still pretty compelling:

http://www.youtube.com/watch?v=KA9AdlhB18o

In this video, a fat girl who believes she is fat because of a "slow metabolism," is tested. It turns out that she has a perfectly normal metabolism but eats a lot more than she realizes.

Here is a similar video:

http://www.youtube.com/watch?v=WGLwzbvx4S4

Scientific research would seem to indicate that this is pretty typical. i.e. people are fat not because of their "slow metabolism" but because they eat a lot more than they realize:

http://www.nejm.org/doi/pdf/10.1056/NEJM199212313272701

Here is a study which looked at a group of people and determined that the fatter subjects had higher metabolic rates than the thinner ones:

http://ajcn.nutrition.org/content/35/3/566.short

If you search, there are a lot of studies like this out there. AFAIK, most (but not all) scientific studies have found that obese people have higher metabolisms than thin people.

My guess is that this is largely because obese people regularly overeat and so their metabolisms rev up a bit in a futile effort to handle the onslaught of calories. There may be a few studies out there which indicate that obese people have slower metabolisms, but I suspect the differences are pretty minor when you look at the real problem: Fat people eat a lot more than they realize, which is something that every study looking at this issue has concluded.

Comment author: Lumifer 27 October 2014 01:11:32AM *  -1 points [-]

the claim is that generally speaking, obesity is the result of having a slow metabolism.

That looks to be a strawman. I am sure you can find on TV, but I am unaware of anyone reasonably serious holding this view.

Comment author: brazil84 27 October 2014 02:57:47AM 1 point [-]

That looks to be a strawman. I am sure you can find on TV, but I am unaware of anyone reasonably serious holding this view.

:shrug: That's what I believed. Anyway, your response is a bit of a True Scotsman argument. If I find 100 people who expressed similar beliefs, you can simply dismiss them as not being "reasonably serious."

Let's do this: How do I know if someone is "reasonably serious" or not?

Comment author: Lumifer 27 October 2014 03:48:23AM -1 points [-]

your response is a bit of a True Scotsman argument

In the same way saying that no one serious believes in perpetual motion machines is also a True Scotsman argument.

How do I know if someone is "reasonably serious" or not?

Has adequate knowledge of human physiology and is not trolling :-P

Comment author: brazil84 27 October 2014 09:35:20AM *  1 point [-]

In the same way saying that no one serious believes in perpetual motion machines is also a True Scotsman argument.

Yes, I would say that it suffers from basically the same same problem. Do you agree that there are people out there who believe, in good faith, that perpetual motion machines are possible? Do you agree that there are people who invest a lot of personal time and energy into constructing perpetual motion machines?

Has adequate knowledge of human physiology and is not trolling :

Okay, and if someone asserts or implies that generally speaking obesity is caused by low metabolism, how do I know if they have adequate knowledge of human physiology and are not trolling?

And let's look at the girls in the two videos they linked. Although they did not make general statements about the causes of obesity, they did seem to believe at the beginning that their obesity was caused by slow metabolism, agreed? Would you agree that those two girls were not trolling? And in your opinion, did they have adequate knowledge of human physiology? If not, how do you know it?

In short, are those two girls "reasonably serious"?

Comment author: Lumifer 27 October 2014 02:58:32PM 0 points [-]

Here I mean "serious" in the external-observer sense -- to denote people whom others consider serious = worthy of attention and time. I do NOT mean "serious" in the internal perception sense (as in e.g. "I'm not joking, I'm serious").

Comment author: brazil84 27 October 2014 04:03:02PM *  1 point [-]

Here I mean "serious" in the external-observer sense -- to denote people whom others consider serious = worthy of attention and time. I do NOT mean "serious" in the internal perception sense (as in e.g. "I'm not joking, I'm serious").

Fine, but please help me figure out where the goalposts are. Are the two girls in the videos I linked worthy of attention and time (at the beginning of the video, before they were scientifically tested)? In your opinion, do they have adequate knowledge of human physiology? If not, how do you know it?

Comment author: Antiochus 20 October 2014 05:49:34PM 0 points [-]

This is interesting enough that I'd like to see some more explanation, too.

Comment author: brazil84 25 October 2014 03:54:14PM 1 point [-]

See my reply to Lumifer above.