Re dei Troll Gozzovigliante

If you cast a creature spell that enters the battlefield as a copy of Feasting Troll King, such as Clone, the enters-the-battlefield ability will trigger.

If you put Feasting Troll King onto the battlefield from your hand without casting it, its enters-the-battlefield ability won't trigger.

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

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).

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.