Proteins are the building blocks of the human body, and they play a critical role in human health and well-being. Dietary protein can be split into two categories: the first is composed of nutritionally indispensable amino acids like histidine, isoleucine, leucine, and lysine. The second component contains nutritionally dispensable amino acids like aspartic acid, asparagine, glutamic acid, alanine, and serine.
A combination of plant-protein foods can serve as a complete and well-balanced source of amino acids essential for all our physiological requirements for this class of molecules.
Soy products are low in sulfur-containing amino acids. Nutrients get denatured by heat, changes in pH, detergents, organic solvents, urea, and other chemicals. Heat treatment of soy flakes (while it inactivates nearly all biologically active components) the protein contained therein retains most of its functionality (Wu et al., 1974).
Soy products are particularly beneficial for cardiovascular and overall health. These are rich in polyunsaturated fats, fiber, vitamins, minerals, and low saturated fat (Sacks et al., 2006).
A 100 g of whey fluid contains 2 percent protein. It is a complete, high-quality protein containing all of the essential amino acids. In addition, it is very digestible, absorbed from the gut quickly compared to other types of protein.
As a dietary supplement, whey protein is widely popular among bodybuilders, athletes, and others who want additional protein in their diet.
Consuming excess whey may cause flatulence in some individuals. The choice of protein – whey or soy is an individual preference. I could not find anything in science that would make me choose between the two.