if you eat the pill whole (not crushed), well, thats really foolish, you should never do that, ever, it's drug abuse! But should you accidently swallow one whole, food won't really have much effect on the plazma concentration - most of the drug is actually absorbed in the intestine track, remember, it's not like Percocet where it's disolved instantly in your stomache, the pill releases a (fairly) steady amount of narcotic over a period of (realistically) 6-8 hours .. if you crush the pill to a dust and then take it, the amount of food in your stomache CAN have an effect on HOW LONG it takes to hit, but eventually you should achieve the same effects (though the fact that it's more drawn out can kinda trick your mind into thinking you're not getting the same effects) ..
NOTE: Food has no effect on the effects of the drug once you have started to feel it! in other words, to answer the question 'Can eating while high on Oxycontin bring down your high?' the answer is no, once you're high the only things that would diminsh the high are time or another drugs (such as Narcan) ..
Still, do you really get HUNGERY while on oxycodone? I have been a daily user (maybe missing no more then 30 days out of each year) for the last 4-5 years, and even now I find hunger is lessened when I am high - but when I first started using, food was the very last thing on my mind at any point from he moment I first inhaled until I woke up the next day..