Ok I know its all confusing. Most of my customers buy Whey. Whey contains more protein than soy per serving. Whey usually taste better and contains more amino acids. It also contains immunoglbans which are good for your immone system. soy is a phyto-estrogen plant it is not the top choice for bodybuilders. It is however the top choice for women. It helps in menopause and pms. It helps to lower cholesterol and good for your bones. most all protein powders are low carb it is the meal replacements that have the carbs. The best tasting powder i have had is something called permi-lean ? i forget how to spell it. I hope that helps any ? on supplements just let me know.