Ketogenic Diet

The Ketogenic Diet is a high fat, adequate protein, low carbohydrate diet, primarily used to treat difficult-to-control (refractory) epilepsy in children. The diet mimics aspects of starvation by forcing the body to burn fat rather than carbohydrate. Normally, the carbohydrates in food are converted into glucose, which is then transported around the body and is particularly important in fuelling the brain. However, if there is very little carbohydrate in the diet, the liver converts fat into fatty acids and ketone bodies. The ketone bodies pass into the brain and replace glucose as an energy source. When the body produces ketone bodies, a state known as ketosis, this has an anticonvulsant effect.

The diet has just enough protein for body growth and repair, and sufficient calories to maintain the correct weight for age and height. The “classic” ketogenic diet contains a 4:1 ratio by weight of fat to combined protein and carbohydrate. This is achieved by eliminating foods high in carbohydrates (starchy fruits and vegetables, bread, pasta, grains and sugar) while increasing the consumption of foods high in fat (cream and butter).

Most dietary fat contains long chain triglycerides (LCT), but a form of coconut oil can be manufactured that contains only medium-chain triglycerides (MCT), which are much more ketogenic. A variant of the diet known as the MCT ketogenic diet uses MCT oil to provide between 30 and 60% of the calories. Carbohydrates and protein can be increased a little, which allows for greater freedom in planning meals.

Developed in the 1920s, the ketogenic diet’s popularity waned with the introduction of effective anticonvulsant drugs. In the mid 1990s the Hollywood producer Jim Abrahams, whose son’s severe epilepsy was effectively controlled by the diet, created the Charlie Foundation to promote it. Publicity included an appearance on NBC’s Dateline programme and .First Do No Harm (1997), a TV movie starring Meryl Streep. The foundation sponsored a multicentre research study and the results, which were published in 1996, marked the beginning of renewed scientific interest in the diet. The potential use of the diet as a treatment for medical conditions other than epilepsy is, as of 2007, still at the research stage.

In 2008, a randomised controlled trial showed a clear benefit for treating refractory epilepsy in children. This added weight to conclusions drawn from the many earlier uncontrolled trials of the ketogenic diet’s efficacy and safety, which already provided sufficient evidence to recommend clinical use. In children with refractory epilepsy, the ketogenic diet is more likely to be effective than trying an alternative anticonvulsant drug. There is some evidence that adults with epilepsy may benefit from the diet, and that a less strict regime, such as a modified Atkins, could be effective.