General slang:
* grub: (common, informal)
* eats: (informal, often used in the phrase "get some eats")
* chow: (informal, often used in the phrase "chow down")
* nosh: (informal, British slang)
* scran: (informal, British slang)
* tucker: (informal, Australian slang)
* vittles: (informal, Southern US slang)
More specific slang:
* munchies: (referring to food cravings, often associated with marijuana use)
* sustenance: (formal, but used sarcastically to refer to food)
* nutrients: (used jokingly to refer to food)
Slang specific to a particular type of food:
* breads: (for bread)
* carn: (for meat)
* za: (for pizza)
The best way to choose the right slang word is to consider your audience and the situation.