 The original therapeutic diet for paediatric epilepsy provides just enough protein for body growth and repair , and sufficient calories to maintain the correct weight for age and height . This classic ketogenic diet contains a 4 : 1 ratio by weight of fat to combined protein and carbohydrate . This is achieved by excluding high @-@ carbohydrate foods such as starchy fruits and vegetables , bread , pasta , grains and sugar , while increasing the consumption of foods high in fat such as nuts , cream and butter . Most dietary fat is made of molecules called long @-@ chain triglycerides ( LCTs ) . However , medium @-@ chain triglycerides ( MCTs ) — made from fatty acids with shorter carbon chains than LCTs — are more ketogenic . A variant of the classic diet known as the MCT ketogenic diet uses a form of coconut oil , which is rich in MCTs , to provide around half the calories . As less overall fat is needed in this variant of the diet , a greater proportion of carbohydrate and protein can be consumed , allowing a greater variety of food choices . 
