Ketogenic Diets for Drug-Resistant Epilepsy

In children with drug-resistant epilepsy, a ketogenic diet decreases the risk of seizures by 50% after three to four months (absolute risk reduction [ARR] = 37.5%; 95% CI, 19.4% to 67.6%; number needed to treat [NNT] = 3; 95% CI, 1 to 5). (Strength of Recommendation [SOR]: B, based on inconsistent or limited-quality patient-oriented evidence.) Adverse effects such as gastrointestinal symptoms do not occur more often than in children who follow their usual diet. In adults, it is unclear whether ketogenic diets are beneficial, and adverse gastrointestinal effects are common.