I have had my high functioning ASD ds on the GFCFSF diet for about 6 months now and he has shown MAJOR improvement. We decided to see if soy affected him, we weren't sure if soy was a culprit or not because we started the diet soy free to begin with just in case. One cup of soy yogurt and the next day he was in La La land and stayed there for 4 days! So OBVIOUSLY soy was a culprit. He is thankfully back from La La land and doing great again. However the other day he accidently drank some cow milk and since he had slipped we thought we might as well let the kid have the milkshke he has been bugging me for for 6 months. So he drank a whole large milkshake and the next day, NOTHING. He seemed fine! Has anyone heard of casein not having an effect and soy having a MAJOR effect. Why would this happen? Now I am wondering about Gluten, but am afraid to try because of how long I hear it takes to clear the system. Anyone else dealt with this? Or know why it would be?