Dr. Elson Hass who has written several books on health and nutrition and is a big proponent of Master-Cleanse stated that many people do have allergic type of reactions to soy products and we should limit the amount of soy we consume. On the hand there have been studies of the many centurions (folks that live 100+ years) that claimed one of the main reasons they live so long is attributed to diet which soy protein was a big part of. Obviously individually we need to choose what works for us. The Master-Cleanse is a great tool to aid us in becoming more aware of how our bodies react to food.