This article is from the Epilepsy FAQ, by Andrew Patrick (firstname.lastname@example.org) with numerous contributions by others.
A ketogenic diet is very rich in lipids (fats) and oils, but low in
proteins and carbohydrates. This unusually high intake of lipids and
oils creates a condition in the body know as "ketosis". The metabolic
shift that is created increases the seizure threshold for some. This
diet is also calory and liquid restricted. The Ketogenic diet is mainly
effective in children. It requires careful preparation and strict
adherence. Although it takes a significant commitment to be successful,
many children have greater seizure control with this diet than with
conventional (drug) therapys. Some are able to reduce or eliminate
antiseizure medications. Careful medical supervision is essential when
using this as a therapy.