Is a fast necessary when initiating the ketogenic diet?

The purpose of this study was to determine time of onset of ketosis and efficacy when the classic ketogenic diet is initiated at full calories without a prior fast in children with epilepsy. A retrospective hospital and neurology clinic chart review was done of all 14 children commenced on the classic ketogenic diet at full calories without a prior fast between January 1, 1997, and May 31, 2001, to determine time to ketosis, time to good ketosis (urine ketones > or =80 mg/dL), and success of the ketogenic diet. Median age at diet initiation was 63 months (25th-75th percentile 47-149 months).