[alistairSH]

It's amazing how much medical knowledge we have to unlearn (and sometimes relearn) as time passes. Some of it from experts; much of it folk wisdom. And how much of that knowledge was based on overzealous extrapolation (as appears to be the case here).

Heat vs Ice for injuries

Fats vs Sugars vs Proteins (and everything else diet-related)

Leeches went out of favor, but now see limited use again (for very specific things, not blanket "release the bad humours!" quackery.

[radlad]

What exactly do we need to unlearn about Fats vs Sugars vs Proteins?

[mb7733]

https://pubmed.ncbi.nlm.nih.gov/18296750:

> 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.

[462436347]

The obesity rate was 30% in 2000, when sugar consumption peaked and the low-carb movement became mainstream. Now the obesity rate is over 40%:

https://cdn.statcdn.com/Infographic/images/normal/11497.jpeg

> Many Americans subscribed to the ideology of low fat

The "low-fat guidelines made people fat" nonsense would carry more weight if people actually followed the guidelines, but they didn't.

[radlad]

Thanks for the link. My understanding is that fats are more energy dense than simple carbs, and therefore eating high-fat diets is more likely to cause weight gain. The article is interesting, but it seems to take for granted that this isn't true. Are there any evidence-based studies you can link?

[mb7733]

The reason I posted that article is because it summarizes how there has been a huge shift in thinking since the low-fat craze. I don't think it takes anything for granted, and I wasn't looking to argue for a particular point of view. I'm sure you can find studies about a specific topic as easily as I can.

Re caloric density: it's true that fat has more cal/g than carbs or protein. But, people do not eat a fixed mass of food per day -- the satiety of the food they consume influences this. Insulin response also affects weight gain and satiety.

[SkyPuncher]

Ancedotally. Growing up, there was a huge push towards "fat-free" and "low fat" foods that is extremely ingrained in my parents generation.

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.

[throwaway5752]

Then, just like now, unscrupulous product marketing and media mistates medical consensus or ascribes consensus where there there is none. Just look at Snackwells. The product marketing term "Doctor recommended" does not mean all doctors, or even specialists in the relevant area.

Unless you are talking to a physician or reading a medical journal, anyone should assume that someone claiming to talk about what the medical community believes is probably wrong and possibly lying.

In the context of the current conversation, reducing saturated fats and bad cholesteral was a reactions to this epidemic https://pubmed.ncbi.nlm.nih.gov/24811552/

After peaking in the mid-1960s, the number of heart disease deaths began a marked decline that has persisted to the present. The increase in heart disease deaths from the early 20th century until the 1960s was due to an increase in the prevalence of coronary atherosclerosis with resultant coronary heart disease, as documented by autopsy studies. This increase was associated with an increase in smoking and dietary changes leading to an increase in serum cholesterol levels

[harimau777]

When I was growing up there was a big emphasis on eating lots of grains which basically equates to lots of carbs. It was also widely believed that fats were bad and contributed to weight gain.

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

[alistairSH]

In my life, eggs have been both bad and good. Butter vs margarine. Atkins vs paleo vs whatever else. Calorie restriction vs more exercise.

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.

[radlad]

Thanks. All of those examples aren't about macronutrients though, which I thought were fairly well understood. (Though I'm sure various myths about them have been spread: such as another commenter suggesting "you can't get fat if you don't eat fat.")

Nutrition is definitely a minefield, I'm with you there!

[jghn]

I'm assuming you never saw folks like Susan Powter making claims of how you can't get fat if you don't eat fat.