Actually, as far as we know, you need to add just as many levels as there are different substances in the human body. Not to mention, things could form structures that are problematic from a mechanical point of view, not just chemical. For example, gout is caused by crystalline formations causing damage to articulations. If you had crysatline formations like those in the stomach or other cavernous or muscular organ, you might have no problem. But, in any bony organ they are extremely problematic. Similarly for sand in the kidneys vs intestines and many others.
The body is much more complex than a collection of proteins.