This page also covers the modified ketogenic diets, the modified Atkins diet and low glycaemic index treatment.
The ketogenic diet can lead to better seizure control for those with some childhood-onset epilepsy syndromes, and for those who don’t respond well to anti-seizure medication.
What is the ketogenic diet?
Dietary treatments for epilepsy have been around for over a hundred years.
The principles of the ketogenic diet are:
- High fat
- Low carbohydrate
- Controlled protein
The ketogenic diet may lead to better seizure control, with fewer side effects than other treatments.
It can also improve alertness and awareness.
Who is the ketogenic diet suitable for?
Under the guidance of a hospital-based epilepsy specialist, the ketogenic diet may be suitable for people with some childhood-onset epilepsy syndromes.
These include:
This rare genetic disorder causes the brain to have a shortage of glucose, its main source of energy.
Seizures are common but not always present and may begin in the first few months of life or in early childhood.
Seizures can include focal onset seizures and generalised onset seizures.
Early-onset absence seizures before three years of age may be a sign of GLUT1.
PDCD is a genetic condition and thought to be rare, though it’s not known exactly how many people have it.
PDCD leads to a potentially life-threatening build-up of lactic acid in the body and causes various neurological disorders (problems affecting the nervous system).
This rare type of epilepsy usually starts in the first year of life, usually between four and eight months old. Seizures usually happen when a child is going to sleep or waking up.
Find out more about Infantile spasms syndrome (West syndrome)
Of all childhood onset epilepsies, one to two out of every 100 are myoclonic atonic epilepsy (Doose syndrome). Seizures usually start between two and six years of age.
Find out more about Epilepsy with myoclonic-atonic seizures (Doose syndrome).
Dravet syndrome, a very rare type of epilepsy that starts in the first year of life. Seizures can include tonic-clonic seizures, clonic seizures, focal onset seizures and myoclonic seizures.
Find out more about Dravet syndrome.
Lennox-Gastaut syndrome is a rare but severe type of epilepsy that affects approximately 1–5% of children with childhood epilepsy.
It affects slightly more boys than girls and causes multiple seizure types.
Find out more about Lennox–Gastaut syndrome.
The ketogenic diet may also be suitable for those who do not respond well to anti-seizure medications or for whom anti-seizure medications are not appropriate.
The diet may be more successful in children and younger teenagers, but it’s difficult to predict who will benefit from the diet. It’s not effective for everyone.
Types of ketogenic diet
There are two different types of ketogenic diet:
- Classical diet
- Medium chain triglyceride (MCT) diet
The choice of diet depends on your child’s age and the food they normally eat.
Research has shown that each diet is equally effective.
How does the ketogenic diet work?
The ketogenic diet alters the body’s metabolism (how foods are converted to energy).
The diet replaces carbohydrates with fats as the body’s major energy source.
When the body doesn't have enough carbohydrates to burn for energy, it burns fat instead and makes things called ketones, which it can use for fuel.
Ketones are natural substances found in the blood and urine.
This state in the body is called ‘ketosis’.
Although we don’t know how exactly ketosis affects epilepsy, achieving and maintaining this state is important for the best possible seizure control.
How can my child be treated with the ketogenic diet?
The ketogenic diet is individually calculated for each child and you’ll be taught how to introduce it to your child.
A consultant (specialist doctor) and a trained dietitian need to supervise the diet closely.
You, your child and your family will also need to be motivated to stick with the diet.
You’ll also need to stay in regular contact with the dietitian. The consultant will help fine-tune the diet and monitor your child's growth and general health with regular blood or urine tests.
They might also prescribe supplementary vitamins and minerals.
While you’re introducing your child to this diet, they should take their anti-seizure medication as usual.
If the diet is effective, the medication can slowly be withdrawn.
What are the side effects?
Common side effects include:
- Constipation
- Vomiting
- Loss of energy
These occur more often when starting the diet and can usually be resolved by adjusting the diet.
Modified ketogenic diets
Two modified ketogenic diets are being used successfully in some children and adults with epilepsy:
- The modified Atkins diet
- The low glycaemic index treatment
They both work in a similar way but are less restrictive types of ketogenic diet therapy.
They are especially useful for children who find a stricter diet difficult, and for older children and adults.
As with all ketogenic diets, a consultant and specialist dietitian should supervise these modified diets closely.
In this diet, the amount of carbohydrate eaten is very low, but there are no fluid, calorie or protein restrictions. Eating fats is encouraged.
The glycaemic index (GI) tells us whether specific foods with carbohydrates raise blood glucose (sugar) levels quickly, at moderate speed or slowly.
Carbohydrates that we absorb slowly have a low GI.
With the low GI treatment, the total daily amount of carbohydrates is higher, but only carbohydrates with a low GI are allowed.
Unfortunately, not all children can get access to dietary therapies due to funding issues or a lack of dietitians in their area.
Find out more about ketogenic diets.
Find out more about GI.
