> This article examines how faith in science led physicians and patients to embrace the low-fat diet for heart disease prevention and weight loss. Scientific studies dating from the late 1940s showed a correlation between high-fat diets and high-cholesterol levels, suggesting that a low-fat diet might prevent heart disease in high-risk patients. By the 1960s, the low-fat diet began to be touted not just for high-risk heart patients, but as good for the whole nation. After 1980, the low-fat approach became an overarching ideology, promoted by physicians, the federal government, the food industry, and the popular health media. Many Americans subscribed to the ideology of low fat, even though there was no clear evidence that it prevented heart disease or promoted weight loss. Ironically, in the same decades that the low-fat approach assumed ideological status, Americans in the aggregate were getting fatter, leading to what many called an obesity epidemic. Nevertheless, the low-fat ideology had such a hold on Americans that skeptics were dismissed. Only recently has evidence of a paradigm shift begun to surface, first with the challenge of the low-carbohydrate diet and then, with a more moderate approach, reflecting recent scientific knowledge about fats.

I can only summarize it as an ingrained feeling of "Fat is what fat people have". It meant they avoided it like the plague while completely overdoing it on other bad stuff.

Both of those ideas may not necessarily have been 100% abandoned but are at the very least now viewed with a lot more nuance.

Lots of junk science. Lots of marketing fluff. But, also lots of recommendations that were assumed correct but didn't stand up to deeper scrutiny.

Note, I'm not saying any of this is bad, or that scientists are stupid and wrong all the time. Just always amazed about how much our understanding of the human body has changed in the last ~50 years.