You said.

> Most people who eat a Standard American/Western Diet (SAD) are ill, as per the article here.

You are proving that most who eat a "Standard American Diet" are sick based on an article specifying what percentage of Americans take a prescription medication but that is a useless metric because its poorly correlated with illness. The example I gave was someone who suffers from seasonal allergies. They would by this metric be classified as ill or sick depending on whether they chose to suffer or medicate and whether their preferred solution was OTC or prescription.

Another good example is early detection of cancer. By your definition Americans who don't die of cancer but live more years would "prove" that people were less healthy by not dying.

This isn't to say that people who eat the standard American diet aren't sick. They are because the standard American diet involves a shit ton of McDonald's, an absurd amount of salt and sugar, and more calories than needed for our sedentary lifestyle.

It is broken in so many obvious ways that wondering if we should change the balance of vitamin A for most folks would be like wondering if a person with a gunshot wound to the forehead ought to do a few more push ups now and again.

* Efficacy vs mechanics

Fiber pretty definitively seems to ease constipation even if our analysis of the mechanism is imprecise or even wrong. Sadly this is not uncommon in medicine. Our understanding is still evolving

* Folk wisdom vs actual wisdom

The peanut thing is a known way to treat allergies but in particular its of very dubious benefit as it is very expensive and requires if I recall complex compliance that parents are liable to fuck up and you are still allergic to peanuts so you STILL have to practice the same behaviors. It's not clear on net that its worthwhile for most parents to use.

> if allergies have "nothing whatsoever to do with diet" these shouldn't exist at all

Any complex condition with substantially divergent outcomes between people is subject to people assigning causation to any irrelevant factor. If they blog about it and 100,000 people try it and 10,000 of them are expected to have substantial improvements if they did nothing you can get yourself 10,000 converts and a line of products.

If I can digress for instance my wife has Rheumatoid arthritis a complex auto immune disorder where the body attacks itself especially the joints having little to do with the common osteoarthritis save for the concurrent effects of one on the other.

A massive number of people know one weird trick the doctors don't want you to know about up to and including drinking your own pee. The truth is that we do know how to slow the progression of the disease but outcomes are wildly divergent between people or even in the same person at different times for reasons we don't understand well. If you convinced enough folks to drink their own pee you would have a certain number whose conditions improve it doesn't mean urine is medicine.

> Yours is the "I exercise and eat kale and I'm healthy, so everyone who doesn't is just lazy and impulsive".

I'm an asthmatic who doesn't get much exercise since I started working from home who drinks about 6-7 mugs of sugary coffee. I'm not fighting the battle of the bulge only because I have always had pretty great metabolism. I like most Americans know my diet and habits aren't very healthy.

Instead of wondering whether I should follow this or that fad I really ought to like most folks do the obvious things.