The ketogenic diet is a high-fat, adequate protein, low carbohydrate diet that has been used for the treatment of intractable childhood epilepsy since the 1920s. The diet mimics the biochemical changes associated with starvation, which create ketosis. Although less commonly used in later decades because of the increased availability of anticonvulsants, the ketogenic diet has re-emerged as a therapeutic option. Only a decade ago the ketogenic diet was seen as a last resort; however, it has become more commonly used in academic centres throughout the world even early in the course of epilepsy. The Atkins diet is a recently used, less restrictive, therapy that also creates ketosis and can lower the number of seizures. Dietary therapies may become even more valuable in the therapy of epilepsy when the mechanisms underlying their success are understood.