The diet consists primarily of foods high in fat, with most of the remaining calories made up of proteins. With the commonly used 3 or 4:1 ratios of fats to carbohydrates and protein, 70% to 90% of the foods are fats and 10% to 30% are carbohydrates and protein. The daily diet often consists of 35 to 45 calories per pound (75-100 calories/kg) and 0.5 to 1.0 grams of protein per pound (1-2 grams/kg) of body weight. Examples of high-fat foods include mayonnaise, butter, and heavy cream. The foods must be carefully measured and weighed. The child is allowed only small portions of cheese, meat, fish, or poultry each day. Fruit is allowed in modest amounts.
MCT (mixed chain triglycerides) is an alternative source of fat. This is a clear light-colored oil that has no flavor. Its use often allows a slight expansion of non-fat foods in the diet. MCT also has laxative properties, beneficial as the ketogenic diet is often constipating. MCT oil should be introduced gradually to avoid stomach cramps.
Because sugar is prohibited in the diet, parents must be vigilant about their children’s medications, cough syrups, vitamins, toothpaste, and any other nonfoods or foods that may contain sugar. Small amounts of sugar can reverse the effects of the diet and cause a seizure. All adults who may be with the child in the parents’ absence must be informed about the dietary restrictions.