Benefits of the nonfasting ketogenic diet compared with the initial fasting ketogenic diet

The ketogenic diet (KD) is traditionally introduced with an initial period of fasting and fluid restriction that is difficult and sometimes complicated by moderate dehydration. This investigation compares the efficacy and tolerability of the nonfasting ketogenic diet (NFKD) and the conventional initial-fasting ketogenic diet (IFKD).

Forty-one children with intractable epilepsy were treated with the NFKD, beginning with a gradual increase in calories with no initial fasting or fluid restriction. This NFKD population was compared retrospectively with 83 recent historical control subjects who were treated with the IFKD. Efficacy, tolerability, time until strong ketosis, and occurrence of complications were compared.

Fourteen (34.1%) patients became seizure-free for at least 3 months after the NFKD, compared with 29 (34.9%) after the IFKD. There was no significant difference in days until strong urinary ketosis between the 2 groups. The incidence of hypoglycemia was also not significantly different between the groups as most other laboratory findings, although the blood urea nitrogen was elevated in 24.1% of the IFKD group and in only 12.2% of the NFKD patients without statistical significance. Conversely, moderate dehydration was significantly less frequent in the NFKD group (12.2%) than in the IFKD group (62.7%). Finally, these results were reflected to the shortening of the hospitalization period in the NFKD group.

These observations suggest that initial fasting and fluid restriction are not essential for the KD and that the tolerability of this treatment may be improved. These data support our intention to conduct a formal, prospective, randomized trial comparing 2 forms of the KD.