The ketogenic diet for intractable epilepsy in adults: preliminary results

Epilepsia. 1999 Dec;40(12):1721-6. doi: 10.1111/j.1528-1157.1999.tb01589.x.


Purpose: Little is known concerning the efficacy and adverse effects of the ketogenic diet in adults with refractory epilepsy. This review reports preliminary results in 11 adults prospectively treated with the diet who had previously failed to gain seizure control with two or more medications and/or surgery.

Methods: Eleven patients nine women, two men), median age, 32.2 years (range, 19-45 years) were treated with the ketogenic diet with a 4:1 ratio with fluid restriction. Six patients had symptomatic partial epilepsy, and five had symptomatic generalized epilepsy. The diet was administered in addition to antiepileptic medication by a multidisciplinary team geared exclusively to adult patients. Medications were not changed while on the diet. Seizure frequency at 8-month follow-up was compared with frequency during a baseline period.

Results: At 8 months of follow-up, three patients had a 90% seizure decrease, three patients had a 50-89% decrease in seizure frequency, one patient had <50% seizure decrease, and four patients discontinued the diet. Of the four patients who discontinued the diet, two had no appreciable change in their seizures despite high ketone levels. Two patients were unable to maintain persistent ketosis at home, despite having done so in the hospital. All seizure types responded to the diet. Common adverse effects included constipation and menstrual irregularities in women. Most patients reported a subjective improvement in concentration. Serum cholesterol and triglycerides increased while on the diet as well as cholesterol high-density lipoprotein (HDL) ratios.

Conclusions: The ketogenic diet shows promise in both adult generalized and partial epilepsy. Persistent ketosis was possible in adults, and the diet was tolerable for most patients. Further study assessing the efficacy of the ketogenic diet, and the cognitive and long-term effects is ongoing.

MeSH terms

  • Adult
  • Age Factors
  • Anticonvulsants / therapeutic use
  • Combined Modality Therapy
  • Diet Therapy / methods*
  • Epilepsy / diet therapy*
  • Epilepsy / drug therapy
  • Epilepsy / metabolism
  • Female
  • Follow-Up Studies
  • Humans
  • Ketone Bodies / biosynthesis*
  • Ketone Bodies / metabolism
  • Ketosis / etiology
  • Ketosis / metabolism
  • Male
  • Middle Aged
  • Prospective Studies
  • Treatment Outcome


  • Anticonvulsants
  • Ketone Bodies