The decline of smoking has made a huge contribution to health. It has also made the obesity statistics look worse. That is especially important to take into account when making inferences from the time series of obesity about the cause of the rise in obesity. The timemoldslimemold blog made part of its argument for environmental contaminants as a cause of obesity from the increase in obesity after 1980, right when smoking was declining. That isn’t the only evidence for the importance of environmental contaminants: wild animals getting fatter and low altitudes being correlated with obesity are especially persuasive. But the time series is part of the argument. All of these possible causes of the rise in obesity should be taken seriously. A multiple-cause story is much more likely to fit the facts.

Here are my blog posts related to the idea that environmental contaminants help contribute to the rise of obesity:

• Are Processed Food and Environmental Contaminants the Main Cause of the Rise of Obesity?

• Livestock Antibiotics, Lithium and PFAS as Leading Suspects for Environmental Causes of Obesity

• How Rising Anorexia Can Go Along with Rising Obesity: Both Can Be Caused By Environmental Contaminants

• How Lithium May Have Led to Serious Obesity for the Pima Beginning around 1937

• Market Opportunities for Helping People Deal with Obesity-Causing Environmental Contaminants

I don’t think I ever relied too heavily on the time series of obesity in judging the argument, since I already thought there were other missing variables—for instance, the distribution in the population of the length of the typical eating window during a day. So I think my posts don’t have to be discounted much at all because of the added complication of the decline of smoking. But some of slimemoldtimemold’s posts that I was riffing on verged a little much toward a monocausal explanation at times.

As I have said many times, the statistical and theoretical issues around explaining the rise of obesity are quite tricky and could be much clarified from having many economists dive deeply into them. Training in economics gives one the right statistical background for epidemiological issues. And economists experiences with economic theory are good mental training for understanding biological mechanisms, despite their different character from economic forces. If you are an economist and want a shot at doing more than $100,000,000,000 worth of good in the world, trying to figure out the causes of the rise in obesity is a great strategy. My advice: Don’t stick to the economists’ lane on this. Go and invade (or be an illegal immigrant in) the territory of the epidemiologists and biologists and dietitians. That is where I think the gold is to be found. If any other economist scolds you for taking on this challenge, I am happy to scold them for scolding you.