The precise effect of the diet on the brain is unknown
A high-fat diet can dramatically reduce or end seizures in children with severe epilepsy, research has shown.
Doctors at Great Ormond Street Hospital tested whether a high-fat, low carbohydrate regime known as a ketogenic diet could have more of an impact than taking drugs to control the condition.
Of the 14 children who have now been on the diet for at least three months, more than half have seen a 50% reduction of seizures.
In four cases, the seizures were reduced by 75%.
Parents also reported that their children have become more alert and responsive while on the diet.
The GOSH team plan to compare the effect of two different ways of giving the diet.
In one version, known as the classical diet, most of the fat comes from naturally fatty foods like cream, butter and oil.
In the alternative, or MCT diet the child receives some fat from naturally occuring food and some from a medium chain triglyceride (MCT) supplement.
Helen Cross, a paediatric neurologist at GOSH, said: "The early findings of this study and others demonstrate that the diet does actually work, with often dramatic effect, in reducing seizures.
"The issue is whether there is indeed any difference between the diets.
"It should be established as a recognised alternative treatment for any child with challenging and resistant epilepsy.
"If this diet was introduced more widely across the UK it could have widespread benefits in the future by reducing the need for medications.
"But, sadly there are only a handful of dietitians in the UK with the expertise and resources to deliver it."
The Ketogenic diet is a high-fat, low-carbohydrate, adequate protein diet which is individually calculated for each child.
First developed in the 1920s it works by altering the body's metabolism by replacing glucose with fats as a major energy source.
The broken down fat produces ketone bodies that help to alleviate seizures.
The diet appears to work in a significant proportion of children, but not every child.
Although it has been used over a long period of time the exact way in which it works is not known.
Parents of children with drug resistant epilepsy interested in taking part in GOSH's Ketogenic diet trials will need to seek a medical referral from their local paediatrician.
This is to assess their child's suitability for the diet, which should only be undertaken with the full support of a paediatrician and experienced dietitian.
Among the children to benefit from the ketogenic diet is eight-year-old Matthew.
He was just nine-months-old when he experienced his first seizure.
Gradually they became more frequent until he was having 10 - 20 type of seizures per day.
Attempts to control and reduce the seizures with different medications had little impact.
However, the effects of six months on a ketogenic diet have been remarkable.
His seizures have been reduced by 80%, and most weeks he is now seizure free.
He now has an average of 2 or 3 different type of seizures a week.
His mother Emma said: "Matthew was always going to be disabled and has the mental age of an 18-month-old.
"Whilst the diet can't repair the damage that has already been done it has improved his life expectancy and quality of life.
"It is a lot calmer at home now. Matthew is more co-operative and happier in himself, which in turn benefits myself and his six-year-old sister.
"His co-ordination has also improved and he now plays with his younger sister.
"The ketogenic diet is something that I wanted him to try this last year but I couldn't find anyone with a dietician specialising in it.
"I think the diet is absolutely fantastic, definitely worth trying and should be made more readily available.
"It can be daunting when starting out as it involves a lot of planning but once you get yourself organised its worth the time and effort."