In my experience some snakes are hungry all the time, this does not mean it needs to be fed. I once feed my burm a rabbit that was close to the max size for him, half an hour later after i walked past his cage, he was in feed mode again or still.
pythons in the wild are oppritunistic feeders meaning they only eat when prey comes close enough, and the snake is succesfull at capturing it. If this happens two or three times in one week then the snake will take the advantage and eat for the possibilty that it could be the last meal for a long time.
also keep in mind that captive snakes can become obese very easily due to the fact that life in a tank can be farily inactive.
Also is it possible that the food item is to small for your snake??
Hope this helped Jason