Just to confuse matters, I always thought that you lost quicker on red days as the green days are more bulky and can slow the weight loss down. That doesn't mean to say you won't lose, it just may be at a slower rate. (I may be completely wrong though - I usually am lol)
I don't do green days very often. Even when trying to lose weight before SW, I don't burn carbs off very fast at all, so I prefer to stick to red days.
I think your right, as are the others who have said...but I only do green days because i am vegetarian, and just got my 3 stone sticker, after starting at end of April......never had a gain either