I would say it's a personal thing for some people. But for me, I noticed that it doesn't make me come down really, but it mellows it out. Cigarettes also seem to do the same.

From what I think, though, the food causing you to come-down might be a placebo of sorts. Does anybody think that too? If you could convince yourself that food doesn't make you come down/dull your high, do you think that it still would? :-P Try it sometime. Do an experiment!

I also have the problem where sometimes I eat too much and get uncomfortable.