Hobbit's Sting deals X damage to target creature, where X is the number of creatures you control plus the number of Foods you control.
Do not eat the delicious cards. No, not even for second breakfast.
Food is an artifact type. Even though it appears on some creatures in other sets, it's never a creature type.
If a Food you control is also a creature, it will be counted twice.
If an effect refers to a Food, it means any Food artifact, not just a Food artifact token. For example, you can sacrifice Lembas, an artifact card with the Food subtype, to activate the last ability of Bill the Pony.
Some spells and abilities that create Food tokens may require targets. If each target chosen is an illegal target as that spell or ability tries to resolve, it won't resolve. You won't create any Food tokens.
You can't sacrifice a Food token to pay multiple costs. For example, you can't sacrifice a Food token to activate its own ability and also to activate the last ability of Bill the Pony.