The Ketogenic diet has been used in treatments for over 60 years and is found to be useful with epilepsy especially among children.
There is research though on the effects of the ketogenic diet on symptoms of Parkinson’s disease. In one study on Parkinson’s disease patients (Van Itallie et al., 2005) there was a 43 per cent reduction in Unified Parkinson’s Disease Rating Scale scores after a 28-day exposure to the ketogenic diet.
All participating patients reported moderate to very good improvement in symptoms. The trial however did not use a control.