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.

You don't choose a target for Curious Forager's ability at the time it triggers. Rather, a second "reflexive" ability triggers when you forage this way. You choose a target for this ability as it goes on the stack. Each player may respond to this triggered ability as normal.

If you don't have enough cards in your graveyard or a Food on the battlefield, you can't choose to forage.

Once you announce that you're casting a spell or activating an ability, players can't take actions until you've finished doing so. Notably, opponents can't try to remove cards from your graveyard or Foods you control to stop you from foraging.