If u throw up food after 5 minutes of eating it, how much calories do u absorb?

None. Because you need to let your intestines absorb it which takes approx 6 hours, and if you throw up from your intestines you can die from various reasons.

Naturally it depends on what the food was, how much of it you retained, etc. Generally it would be very little.

It's a really bad idea to throw up "voluntarily" in order to get the pleasure of eating something without absorbing many calories. This is because the hydrochloric acid in your stomach digestive juices is very, very strong. Your stomach lining is designed for it, but your throat, mouth, and teeth are not. It doesn't take long to develop permanent damage to those parts of your body, even your taste buds.

Approximately 13.85 calories per spew.

i wouldnt do that, you will be messing up your stomach, not worth it, theres better ways to lose weight

So you don't mind acid burning your throat and teeth so they rot out fast? You don't mind the possibility of mouth or throat cancer from the acid? If you die from the cancer you will never have to worry about calories again!