Description:The KD works quickly when effective, typically within the first 1–2 weeks. Starting the KD after a fasting periodmay lead to a more rapid, but equivalent long-term seizure reduction, confirming prior reports. If the KD has not led to seizure reduction after 2 months, it can probably be discontinued.
Kossoff (2008). "When Do Seizures Usually Improve With The Ketogenic Diet?" Epilepsia 49(2): 329-333.