 Almost half of children and young people with epilepsy who have tried some form of this diet saw the number of seizures drop by at least half , and the effect persists even after discontinuing the diet . The most common adverse effect is constipation , affecting about 30 % of patients — this was due to fluid restriction , which was once a feature of the diet , but this led to increased risk of kidney stones , and is no longer considered beneficial . There is some evidence that adults with epilepsy may benefit from the diet , and that a less strict regimen , such as a modified Atkins diet , is similarly effective . Clinical trials and studies in animal models ( including C. elegans ) suggest that ketogenic diets provide neuroprotective and disease @-@ modifying benefits for a number of adult neurodegenerative disorders . As of 2012 , there is limited clinical trial data in these areas , and , outside of paediatric epilepsy , use of the ketogenic diet remains at the research stage . 
