Ketogenic diet

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The ketogenic diet is a low carbohydrate, high fat diet that is used to treat epilepsy which has not responded to other treatments. The diet was first developed nearly a century ago and was typically used only with children until recently. The diet is designed to force your body to burn fat instead of glucose for energy. This produces ketones, which give the diet its ‘keto’ name and which have an anti-epileptic effect. The diet should only be used under the supervision of a dietitian who will work out a diet prescription based on your individual needs and requirements. New developments have made it easier to prepare and follow.

Different types of ketogenic diet therapy

There are different forms of the diet including the classical diet, medium chain triglyceride (MCT) diet, ketogenic diet, modified ketogenic diets (modified atkins and the low glycaemic index diet). If you are not able to eat or drink special ketogenic tube feeds can be used.

Classical diet: Carbohydrates, proteins and fats are measured to provide the ratios needed for this version of the diet. The higher levels of fat to carbohydrate and protein in this diet are usually in ratios of 4:1, 3:1 and 2:1. To explain what these ratios mean a 3:1 diet means 3 times the amount of energy is provided by fat and the foods used include lots of cream, mayonnaise, margarine, oil and butter with prescribed supplements. Proteins are necessary for growth and are provided by foods like meat, fish, eggs, or cheese. Carbohydrate is limited to small portions of vegetables or fruit.

The medium chain triglycerides (MCT) diet is an alternative to the classical diet and the main difference is that fat from MCT such as oils or emulsions sources is included usually in all meals. This allows greater freedom on carbohydrate and protein foods. MCT oils and emulsions are available on prescription.

Modified ketogenic diets are very similar to other versions of the diet in that they are very low in carbohydrate and high in fat. The advantage with the modified diet is a greater choice of foods. The main focus is carbohydrate counting as well as making sure you have enough calories from fats. This can be a really good option for older children, teens and adults who eat regularly and are willing to monitor carbohydrate and fat intake through the day.

The foods

The diet is easier to follow now than ever before. There are special ranges of readymade products available with the fat to carbohydrate ratios already calculated. These products come in powders, liquids, oils, sachets and fat emulsions for use in meals, drinks and tube-feeds. There are also recipe books for each of the diet types. More information is available from Matthew’s Friends, a UK-based charity who support families in the use of the diet and provide information. See www.matthewsfriends.org.

Which diet is suitable for me?

The dietitian will help you choose a diet that works for you. The choice of diet will depend on your age, dietary preferences and lifestyle as well as any practicalities for the family. New computer programmes or exchange lists can be used to develop recipes and make it easier to put into practice. Vitamin and mineral supplements may be needed.

Is the diet effective?

All ketogenic diets have been shown to be successful in the treatment of epilepsy. Some people have become completely seizure free on the ketogenic diet while others have had fewer seizures. Most work in the area of the ketogenic diet has been with children with 25% reaching seizure freedom and 80% reducing seizures. Among adults about one third (33%) achieve seizure reduction of more than 50%. In addition to reduced seizures, both children and adults following ketogenic diets can benefit from a reduction in the number of drugs needed to treat their seizures and from a reduction in side effects. They can also benefit from improvements in alertness, energy, behaviour and well-being.

Epilepsy Ireland wishes to thank Laura Healy from St James's Hospital for her input into this section.