There are two phases to dumping. Early dumping (sweats, heart racing, etc.) can hit as soon as 15 minutes after eating or drinking depending on the food. Late dumping (that low sugar crash) usually hits after 1-2 hours after.
I think it depends on the person. I am 5 months out, and have never dumped. I usually follow my diet to the letter, but at thanksgiving I had a piece of pumpkin pie and was fine. (Except for the guilt afterwards LOL)
