The ketogenic diet is a high-fat, adequate-protein, low-carbohydrate diet that has been used since the 1920s to treat intractable childhood epilepsy. It works by increasing ketone body production which is thought to have anti-seizure effects. A randomized controlled trial in 2008 found that 38% of children on the ketogenic diet experienced at least a 50% reduction in seizures, compared to only 6% of children in the control group. Common side effects include kidney stones and slowed growth in young children on the diet long-term.