Your girlfriend might try to change nutrition habits, if possible, and place more emphasis on breakfast and dinner, eating different food, more fruit and vegetables. The reason I suggest breakfast and dinner is because the time distances between the meals is longer so that the food is well digested. Furthermore, she might request a few laboratory tests (blood tests) to identify possible or eventual disorders. Nutrition problems are sometimes caused by mental conflicts, too especially among a younger population...so she might seek help with a counselor or mental health professional to assess her attitude toward food, eating, and self-image.