In Fannie Flagg's Fried Green Tomatoes at The Whistle Stop Cafe, Evelyn Couch's life is changed when she meets Ninny Threadgoode because Ninny's stories about her life and her family's life are so full of energy, ambition, and love. Seeing someone else have that much ambition and love in her life makes Evelyn feel ambitious about improving her own life.
Evelyn Couch, just as her last name symbolizes, is a heavily obese, middle-aged woman who is suffering from depression because she feels she is useless. In contrast, Ninny has had a rich, full life in which Ninny's sister-in-law Idgie ran a cafe. More importantly, it becomes clear from Ninny's stories of her past that her family was one that was full of love for each other and love for other people.
One example can be seen in the fact that, since Ninny's stories take place during the days of segregation in Alabama, Idgie decided to sell meals to African Americans at the back door of the cafe and refused to stop when the sheriff warned her the Ku Klux Klan might come to terrorize her. Other examples can be seen in how the family united to take care of abused Ruth.
The recount of all of this love helps Evelyn forget her own problems and eventually forgive all around her, even herself. She even becomes healthy again staying at the Forever Slim Lodge in California.