What does it mean when food shoots through you within minutes?

Sometimes when I eat something that shocks my body that it doesnt like- it upsets my stomach in a matter of minutes and it goes right through me. I want to know what exactly is happening to my insides when this occurs as far as digestion, as far as intestinal flora, etc. Does the food even get digested if its out of me within 10-20 minutes? Does the body just force it through without filtering it?

Obviously I know not to eat as much or eat the same product again because my body doesnt like it. I just want to know from a mechanical and scientific stand point what happens. Thanks!