BMI in the 20th Century

https://www.lesswrong.com/posts/NRrbJJWnaSorrqvtZ/on-not-getting-contaminated-by-the-wrong-obesity-ideas

A Chemical Hunger (a), a series by the authors of the blog Slime Mold Time Mold (SMTM), argues that the obesity epidemic is entirely caused (a) by environmental contaminants. 

In my last post, I investigated SMTM’s main suspect (lithium).[1] This post collects other observations I have made about SMTM’s work, not narrowly related to lithium, but rather focused on the broader thesis of their blog post series.

I think that the environmental contamination hypothesis of the obesity epidemic is a priori plausible. After all, we know that chemicals can affect humans, and our exposure to chemicals has plausibly changed a lot over time. However, I found that several of what seem to be SMTM’s strongest arguments in favor of the contamination theory turned out to be dubious, and that nearly all of the interesting things I thought I’d learned from their blog posts turned out to actually be wrong. I’ll explain that in this post.