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.
Except for the listed exceptions, the token copies exactly what was printed on the original creature and nothing else (unless that creature was itself copying something else; see below). It doesn't copy whether that permanent was tapped or untapped, whether it had any counters on it or Auras attached to it, or any non-copy effects that changed its power, toughness, types, color, and so on.
If something becomes a copy of the token, the copy also has base power and toughness 1/1, is a Food Golem artifact creature in addition to its other types, and has "
, 
, Sacrifice this artifact: You gain 3 life."
If the copied creature was copying something else, then the token enters the battlefield as whatever that creature copied, with the stated exceptions.
If the copied creature had 
in its mana cost, X is 0.
Any enters-the-battlefield abilities of the copied creature will trigger when the token enters the battlefield. Any "as [this creature] enters the battlefield" or "[this creature] enters the battlefield with" abilities of the creature will also work.
, , Sacrifice this token: You gain 3 life."
