Soy Protein. Good or Bad? in Health & Nutrition Programs Posted January 19, 2012 The problem with soy protein is it is made up of isolates. Feel free to ask Dr. McDougall MD but he has seen studies that it increases IGF-1 (which increase mutagenisis) aka cancer growth. Stick with hemp it has the a BCAA closest to our muscle body type and is very well assimilated.