Regarding (3) and (4), do you believe it likely that nutritional science is wrong in their broad strokes, e.g. that a diet comprised of cheetos and bacon is good for you, while a diet comprised of green vegetables, rice and legumes is bad for you?

Nutritional science occasionally gets small details wrong, lard fries vs trans fat fries. They are spot on for most things, e.g. spinach vs fries.