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by jeffreyrogers·3y ago·view on hn ↗
Doesn't the existence of anorexia (which appears to be socially transmissible) and the fact that people who take up hobbies like bodybuilding are able to manage their fat levels well suggest that environmental contaminants aren't the whole story? The staple bodybuilding foods are rice and chicken breast. That's about as industrialized as you can get.

If there were people getting fat eating broccoli, potatoes, chicken, and salad I would buy the contamination argument, but when you look at what people who have trouble managing their weight actually eat it is never simple foods like that.

2 comments
There is the idea of a "lipostat" which is the mechanism of the body to regulate it's weight. In a person with obesity or anorexia, the lipostat would be off, so the body would be trying to maintain a higher or lower than regular weight. (I think I read about it first on the slimemoldtimemold blog).

The interesing thing is, in case of underweight, the lipostat might not just cause reduced hunger and increased body temperature for example. It might also affect self-image and cause you to feel you are too fat. This is still speculation of course, and I can imagine that it makes people uncomfortable, since we like to believe our self is in control of our body and not the other way around. But it is entirely possible that "socially transmissible" or seemingly "cultural" disorders are intertwined in a complex way. (What if you need certain widespread contaminants, or microbiome deficiencies, plus trauma experience or unhealty body images in media to cause anorexia.)

> Doesn't the existence of anorexia (which appears to be socially transmissible) and the fact that people who take up hobbies like bodybuilding are able to manage their fat levels well suggest that environmental contaminants aren't the whole story?

No? Genetics is the best predictor of obesity, but as with drugs any contaminant would have varying degrees of effect on the population, including sometimes a paradoxical effect.

> If there were people getting fat eating broccoli, potatoes, chicken, and salad I would buy the contamination argument, but when you look at what people who have trouble managing their weight actually eat it is never simple foods like that.

And a whole lot of people are not getting fat at all eating foods like and barely exercising. Why do some people have to pay attention to what they eat and others don't? Why has the percentage of the population that is obese increasing?

Paradoxical effects are rare and tend to happen only with psychoactive medications. I see very little evidence for paradoxical effects playing a major role, but obviously it can't be ruled out entirely. I don't find paradoxical effects a convincing explanation for anorexia because of how people develop anorexia. You can become anorexic merely by changing your social circle or even your desired social circle, so why would a paradoxical effect occur in that situation when presumably the environment hasn't changed in terms of chemical consumption.

> Why has the percentage of the population that is obese increasing?

Most likely explanation is that they are eating foods that aren't satiating and that are high calorie, foods that weren't common in the past. Like I said earlier, people who are eating simple foods like the ones I listed don't get fat. Genetics seems to play a role in that some people can eat junk and feel full but most can't.

There can be more than one cause for a trend increasing. The way to look at it would not just be to observe anorexia but also whether or not there has been an increase in the merely underweight in the same time frame as the obese. People who eat and are just sated with very little intake. I am not aware of any data on this.

> Most likely explanation is that they are eating foods that aren't satiating and that are high calorie, foods that weren't common in the past. Like I said earlier, people who are eating simple foods like the ones I listed don't get fat.

And as I said I don't think this stands up to scrutiny, and I said why already. Additional: obesity is increasing in wild animal populations too.

On a personal level, I have eaten diets of only foods like you've mentioned and I would still have gone well over my calorie limit if I had done so until sated. As far as I can tell 'satiating foods' is a term with no real science behind it. Believe me, if I was aware of something aside from hardcore stimulants that would actually keep my appetite in check I'd have been eating it for the past 15 years instead of suffering.

The wild animals that become obese are ones that have access to human food and garbage. It's not like fish swimming in the runoff from chemical plants become obese (they develop other disorders but not obesity as far as I'm aware).
Again, this explanation doesn't stand up to scrutiny. Lab animals in controlled environments are also getting fatter: https://royalsocietypublishing.org/doi/abs/10.1098/rspb.2010...
Those aren't wild animals.