Why isn’t a 100% protein food possible.

Question

I’m sure most nutrition-conscious people are aware of the 1g protein/10 calorie ratio for determining whether a food is high protein. To my knowledge the highest protein foods & supplements out there have a 2/10 ratio, but theoretically shouldn’t a 2.5/10 be possible, since 1g of protein generally contains 4 calories (I am aware this is a rounded up figure that can vary, but that only furthers my inquiry). What is the scientific reason for this? Is it impossible for a molecule to fully consist of proteins, so the remaining 2ish calories have to consist of other macronutrients, or is it something else?

In: Chemistry

Answer 1

This is a bad idea. You should never exclusively eat protein. This causes [protein poisoning](https://en.wikipedia.org/wiki/Protein_poisoning).