“Soul Food” tells the story of a big African-American family from Chicago with warm-hearted good cheer; in the way it cuts between stories of romance and trouble, it’s like “Waiting to Exhale,” but more down to earth and believable—and funnier. It knows how black families stay in constant communication down three or four generations and out to third cousins—how when a matriarch like the movie’s Big Mama hosts a holiday dinner, there are going to be a lot of people in the house, and a lot of stories to catch up on.