[fuzztester]

>If general, I would say that cooking proteins fundamentally changes the food and makes it more digestible (meat, fish, eggs, etc.)

Applies to vegetables and other vegetarian foods, too :)

Ever tried eating raw wheat, rice, pulses or vegetables? Only some vegetables are okay in salads.

[fuzztester]

And cooking fundamentally changes the food because cooking is a chemical and physical reaction caused by the heat on the food being cooked. Proteins get denatured, food gets softer or harder (depending upon the amount of liquid and heat added or removed), etc.

I am not a expert on the science of cooking, these are just my casual, slightly scientific observations as a layman :)