I think that may be true for peak performance, but there are other tradeoffs. I've noticed many older athletes adopting plant based diets for longevity reasons.

For ordinary health purposes, I don't think anyone who's eating a whole food type diet will be struggling for protein, as long they're eating some beans/nuts/seeds/eggs/dairy/meat/etc.

I have heard that sources of protein matter: animal vs plant

Animal protein has more efficacy than plant protein


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Since you have such an interest in health science, I suggest looking into "endogenous water". 