The artifacts retain any types, subtypes, supertypes, and abilities they have.

You can't activate the first level ability of a Class unless that Class is level 1. Similarly, you can't activate the second level ability of a Class unless that Class is level 2.

If Gourmand's Talent somehow becomes an artifact, it will also be a Food during your turn.

Each Class starts with only the first of its three class abilities. As the first level ability resolves, the Class becomes level 2 and gains the second class ability. As the second level ability resolves, the Class becomes level 3 and gains the third class ability.

There's no restriction on how many Class permanents you can control, whether they're the same or different classes. Each Class permanent tracks its own level separately.

Each Class has five abilities. The three in the major sections of its text box are class abilities. Class abilities can be static, activated, or triggered abilities. The other two are level abilities, one activated ability to advance the Class to level 2 and another to advance the Class to level 3.

Gaining a level is a normal activated ability. It uses the stack and can be responded to.

The level 2 and level 3 class abilities of Gourmand's Talent won't trigger if you already gained life earlier in the turn on which it gained those levels, even if you gain life again later in the turn.

Gaining a level won't remove abilities that a Class had at a previous level.

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.