Food is a healing item in Skylanders: Spyro's Adventure. They are found in levels either lying around, in wooden containers, or dropped by defeated enemies. Although they comes in many versions, from watermelons to Chinese take-outs, they always restore 120 health points to the Skylander eating them. Food can not be found in the Ruins.
Lore Tablet Entry
The differences between snacks and Food are subtle but significant. Snacks generally come from the Elements and their nutritional value is somewhat dependant on the Skylanders Hero Level. It is also true that snacks have never been known to result in bees shooting out from one's nose. Then again, neither has food.