Five Fundamental Facts on Protein 1. All amino acids are found in all plants in different ratios. 2. The only way to become deficient in protein is to eat highly processed foods - white sugar, oil, or to eat too few kcals, as in malnourishment or anorexia or a specific health condition. 3. Excellent sources of amino acids include legumes, nuts, seeds, mushrooms, and vegetables. Hence the handy list I always refer to: vegetables, fruits, whole grains, legumes, mushrooms, nuts, seeds, herbs, and s