I’d like to clarify something I’ve noticed not everyone gets right: what it means for a protein to denaturate.
Proteins are large chains of amino acids that, when folded a certain way, are catalysts to specific chemical reactions in the human body. Proteins need to be in precise three dimensional shapes to do this. This shape is affected by temperature, acidity, and many other factors. See the wikipedia article on protein denaturation.
However, we look upon protein as a nutritional source, a source of amino acids. Proteins do not have to be in working order for us to be able to get our nutritional needs, because we needs amino acids, not protein per se. Therefore, denaturation of proteins is no problem nutrition-wise.
For example: most humans use meat as their main source of proteins. Almost all meat is cooked before consumption, denaturing most proteins. Nevertheless, these humans don’t die of protein insufficiency (pfooh!).
However, if you add a certain protein to enhance your metabolism, it could be very important that the protein does not denaturate. For example: if you add amylase to improve starch breakdown, you should not cook the amylase.
Yup - to add less technical language to the OP, we naturally use enzymes and acid to chop up proteins in the digestive system anyway, so it doesn’t matter what interesting shape we get them into through heating.