If an effect refers to a Food, it means any Food artifact, not just a Food artifact token. For example, you can sacrifice Tough Cookie (an Artifact Creature — Food Golem) to activate Maraleaf Rider's ability (an ability with "Sacrifice a Food" in its cost).

Food is an artifact type. Even though it appears on some creatures, it's never a creature type.

You can't sacrifice a Food to pay multiple costs. For example, you can't sacrifice a Food token to activate its own ability and also to activate Maraleaf Rider's ability.

Whatever you do, don't eat the delicious cards.

When Of Herbs and Stewed Rabbit's first chapter ability triggers, you can choose not to target a creature just to create a Food token. However, if you do choose a target, and that target is illegal at the time the ability tries to resolve, the ability won't resolve and none of its effects will happen. You won't create a Food token.