What is this episode from the show '3rd rock from the sun' called?

it was an episode where female aliens come to earth and sally wants to join them and the alien women teach sally how to be like them and then they overtake a lot of stores and one of the women calls mary plus-sized because she wears a size 8. And sally takes a small bite of a french fry and she says she's full. those are the only details that i can remember from the episode. thanks a lot if you figure it out!