In a multiplayer game, opponents who have left the game aren't counted by Gluttonous Troll's triggered ability.

You can sacrifice a Food token created by Gluttonous Troll's triggered ability to pay for the cost of its activated ability.

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

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

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.