I'm curious about different high heat cooking methods. What is acceptable and what is not.

Steaming is completely okay?

But then fruit juice is usually made with a steaming extraction process, and that's supposed to be bad? (I know fruit juice has too much sugar anyway and why toss the pulp we need.)

I am also confused because some people bake at 350-450 with paleo ingredients, or bake/grill fish and meat at these temps?

I'm confused because I read that stir-frying is paleo-accepted. Maybe not by the hardcore people, but most say that you're using high heat for a relatively short time.

But toasting and roasting nuts and seeds is bad? I want to soak and dehydrate nuts to get the phytic acid out, but can I toast them too without destroying nutrients?