 Another difference between older and newer studies is that the type of patients treated with the ketogenic diet has changed over time . When first developed and used , the ketogenic diet was not a treatment of last resort ; in contrast , the children in modern studies have already tried and failed a number of anticonvulsant drugs , so may be assumed to have more difficult @-@ to @-@ treat epilepsy . Early and modern studies also differ because the treatment protocol has changed . In older protocols , the diet was initiated with a prolonged fast , designed to lose 5 – 10 % body weight , and heavily restricted the calorie intake . Concerns over child health and growth led to a relaxation of the diet 's restrictions . Fluid restriction was once a feature of the diet , but this led to increased risk of constipation and kidney stones , and is no longer considered beneficial . 
