"All proteins are made up of the same amino acids. ALL. No exceptions. The difference between animal and vegetable proteins is in the content of certain amino acids. If vegetable proteins are mixed, the differences get made up. Even if they aren't mixed, all you need to do to get the right amount of low amino acids is to eat more of that food. There is no 'need' for animal proteins at all."
—Marion Nestle, Department of Nutrition, Food Studies, and Public Health, New York University