Anything to bulk up diet?

I'd also like someone to go into these types of diets into a bit more depth.

I'm of European (English as far back as I can find) descent, so can someone please be a little more specific on what a strong consistent diet would entail.

Simply saying fish, lamb etc is fine, but how do you prepare it? Are you allowed to add sauces such as gravy, etc? Or just by itself.

With a strong vegetable diet, should you boil, bake etc? And what vegetables are consistent with the northern parts of England? Potatoes haha. Thats all I can think of.

Thanks for your help.