I have not noticed anything. I think sometimes to deal with hunger its easer to leave it as late as poss, becuase I often don't feel hungry till lunch time. So if I have my first shake then I still have the rest of my allowance. I like to keep something for super. I find that the hardest time. However, sometimes If I'm in a rush and going to be out all day I have to have a shake as soon as I get up, or I wont have enough time to fit them all in.
I think just what ever works for you