Multiple forms of the ketogenic diet (KD) have been successfully used to treat drug-resistant epilepsy, however its mainstream use as a first-line therapy is still limited. Further investigation into its clinical efficacy as well as the molecular basis of activity is likely to assist in the reversal of any resistance to its implementation. In this review we shall attempt to elucidate the current state of experimental and clinical data concerning the neuroprotective and cognitive effects of the KD in both humans and animals. Generally, it has been shown by many research groups that effective implementation of KD exerts strong neuroprotective effects with respect to social behavior and cognition. We will also elucidate the role of KD in the interesting relationship between sleep, epilepsy and memory. Currently available evidence also indicates that, under appropriate control, and with further studies investigating any potential long-term side effects, the KD is also a relatively safe intervention, especially when compared to traditional anti-epileptic pharmacotherapeutics. In addition, due to its neuroprotective capacity, the KD may also hold potential benefit for the treatment of other neurological or neurodegenerative disorders.