Clinical efficacy of the ketogenic diet.

The ketogenic diet is an effective alternative therapy used to control intractable seizures. It was originally described in 1921 as a way to duplicate and prolong the beneficial effects that fasting appeared to have on seizure control. It involves consuming a calorie-restricted diet in which the fat:carbohydrate + protein ratio ranges from 2:1 to 5:1. Recent prospective studies in children demonstrate that about 50% of children will continue on the diet for at least a year, with 40-50% of those starting the diet having a >50% reduction in seizures after 12 months. When the diet is discontinued it is usually due to lack of efficacy. The diet is a radical medical therapy and nutritional well-being is a constant concern. Renal stones have occurred in 5-8% of children on the diet; lipids are elevated, but the significance of this is not known. The mechanism of action of the diet remains unknown, and it is difficult to assess which biochemical parameters should be monitored as adjustments are made to the diet.