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Ketogenic diets
DefinitionKetogenic diets are a group of high-fat, moderate-
protein, and very low-carbohydrate diets given to treat
some children and adolescents with epilepsy, and some
adults with epilepsy and other diseases. The name
ketogenicrefers to the increased production of ketone
bodies as a result of this special diet. Ketone bodies are
three compounds that are formed during themetabo-
lismoffatsand are ordinarily excreted in the urine. An
abnormally high level of ketone bodies is called keto-
sis, and this condition is the goal of the ketogenic diet.
It is thought that ketosis helps to control the frequency
and severity of epileptic seizures, even though the
reasons for this effect are not fully understood as of
2007.
OriginsIt has been known since Biblical times that some
people with epilepsy were helped by prolonged periods
of fasting, with good results. In earlier periods of
history, children were kept on clear liquids for as
long as two or three weeks until their seizures
improved. This type of fasting, however, was obvi-
ously not sustainable as a long-term treatment. In
1921, a doctor at the Mayo Clinic named R. M. Wilder
devised a diet for patients with epilepsy that was
intended to mimic the biochemical changes that take
place during fasting—ketosis, acidosis, anddehydra-
tion. Dr. Wilder’s ketogenic diet provided 10–15
grams ofcarbohydratesper day, 1 gram ofprotein
for each kilogram of the patient’s body weight, and the
remaining calories from fat. The calorie level was 75%
of the normal daily allowance for the patient’s weight,
and fluids were restricted to 80 percent. Wilder’s diet
was almost identical to the protocol used at Johns
Hopkins in 2007.
Until the late 1930s, the Mayo Clinic ketogenic
diet was used to treat adults as well as children with
epilepsy. In 1938, however, the first anticonvulsant
drug—phenytoin (Dilantin)—was introduced, and
was quickly followed by others. As of the early
2000s, there are 20 different anticonvulsant medica-
tions given to patients with epilepsy. After these med-
ications were introduced, people were less interested in
the ketogenic diet; many doctors considered it
unnecessary or too much trouble. The number of hos-
pitals that used it as therapy fell off sharply, while
many practitioners regarded it as a ‘‘holistic’’ or even
‘‘alternative’’ treatment for epilepsy.
Interest in the ketogenic diet was reawakened in
the mid-1990s, when the father of a 2-year-old with
seizures that had not responded to any medications or
surgical procedures read about the diet in medical
textbooks. He started his son on the ketogenic diet
with very good results; the child stopped having seiz-
ures and was able to discontinue his medications. The
father then established the Charlie Foundation, which
continues to provide information and guidance about
the ketogenic diet to parents, dietitians, and other
health care professionals. Since 1994, the diet has
been generally accepted by doctors; it is used in
about 40 countries around the world for the treatment
of childhood epilepsy. The costs of the diet are reim-
bursed by most insurance carriers in the United States.DescriptionClassic ketogenic diet (Johns Hopkins protocol)
The ketogenic diet used at the Johns Hopkins
Pediatric Epilepsy Center is commonly considered
the standard or classic form of this diet. Its usual
protocol for children between the ages of 3 and 12
years provides a ratio of 4 parts fats to 1 part protein
and carbohydrates combined. Infants, toddlers, and
adolescents are usually started on a 3:1 ratio. Individ-
ual patients may require ratios ranging from 2.5:1 to