Comment by briefcomment | Hacker News Reader

Comment by briefcomment | Hacker News Reader

> "Something seems to have changed. But surprisingly, we don’t seem to have any idea what that thing was."

We have ideas. Polyunsaturated fats (shortening, margarine, soybean oil, canola oil, even chicken fat) is a promising culprit. Consumption of those have skyrocketed in the last half of the 20th century [1]. Full study here [2].

It seems that polyunsaturated fats induce hibernation like symptoms, which could explain weight gain. This blog is a fascinating look at some of the literature [3]. Good summary post [4].

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3076650/figure/...

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3076650/

[3] https://fireinabottle.net/every-fire-in-a-bottle-post-from-t...

[4] https://fireinabottle.net/are-you-in-deep-torpor-scd1-theory...

I feel that this was covered by the article (there's a second part) with the conclusion that this cannot be the main factor of the obesity epidemic. Margarine consumption was much higher in the 1970s than today, but obesity today is much higher.

I don't see any of this covered in the second or third article (apart from a comment in the second article that provides some additional interesting details on this hypothesis).

There may be a generational effect at play, causing the symptoms to be more pronounced in the offspring of the high margarine cohort. Certain interventions effect second and third generation offspring. You can induce sterility in the third generation by an intervention in the first generation for example.

That being said, canola oils and soybean oil are more used than ever.

I thought polyunsaturated fats ( fish, soybean ) were fairly prevalent in Japanese diets?

How does that square up with the lower prevalence of obesity there?

Eating isolated oils is decidedly different from eating whole foods, as there are compounds that counteract each other when taken as a whole. For example, fish have long chain fatty acids which counter some effects of the Omega oils.

I think it's much easier to consume large portions of soybean oil if you're using it as an all purpose oil, than if you were just eating tofu, bean curd, natto, etc.

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