Food has been used as a metaphor and a costar thousands of times in films.
The Hours threaded together the lives of the 3 women with the use of food. More accurately eggs. As each character began their decent into their own depression, they were put in a scene where eggs were being broken. Giving the visual of how fragile the human mind can be.
The Jane Austen Book Club, used the theme of food as a comfort element. From the first book club meeting which takes place in a busy coffee shop to the community table at the end, we are shown how each character grows more relaxed with each other. Over the course of the film, the more intense the topic or atmosphere the less nutritious the food in the scene. (when they are talking about Sense and Sensibility in which Grigg and Jocelyn fight they are eating donuts, or when Prudie has to tell her mother to leave, her mother is eating brownies and ice cream)
Under the Tuscan Sun, food is used as a measure of faith and accomplishment. The lead character starts off on top of the world, with her homemade brownies being used to show her pride and ego. As the story progresses, she's seen loosing that sense of self (dinner with the neighbours and the bitter olives) only to regain it near the end when she feels she's finally standing on her own two feet again (the 7 course meals she makes for her construction crew).
Just a little taste of what I have been noticing in some of my favourite films.