Health has always been like this, even in ancient times. The biology is brain-meltingly complex so anxious and frustrated folks will be more open-minded to any explanation that offers a path to relief, especially if an expert has failed us in the past.
A forum offers much but I agree there are no safe zones where we can abandon empirical skepticism. I prefer the broad patterns, i.e. the fewer manufactured foods/drugs/stimuli we take in the fewer fine details we need to know.
Lots of: urban hiking, cycling, sprinting
Lots of: fresh meat, seafood, eggs, organs, tubers, starch fruits, vegetables, meat fat, dairy fat, oil fruits
Some: cured meat, dairy protein, sweet fruits, rice, pulses, tree nuts, oil seeds
Minimal: soy, refined proteins, sugar, liquid carbohydrate, grains, refined oils, peanuts