The largest single-institution intention-to-treat prospective study[4] conducted on 150 patients at the Johns Hopkins Hospital demonstrated that at 3 months (with 125 patients remaining on the protocol) 3% of patients were free from seizure, 31% had a greater than 90% reduction in seizure frequency, and 26% had a 50–90% reduction in seizure.[5] After 12 months (with 83 patients remaining on the protocol), 7% were free of seizures, 20% had greater than 90% reduction in seizures, and 23% had of 50–90% reduction in seizure.
Neal et al.[6] conducted a randomized controlled trial to study the efficacy of ketogenic diet in controlling seizures. They enrolled 145 children aged between 2 and 16 years who had daily seizures (or more than seven seizures per week), had failed to respond to at least two antiepileptic drugs, and had not been treated previously with the ketogenic diet. Seventy-three
children were assigned to the ketogenic diet group and 72 children to the control group. Data from 103 children (54 from the ketogenic diet group and 49 from the control group) were available for analysis.