 The ketogenic diet may be a successful treatment for several rare metabolic diseases . Case reports of two children indicate that it may be a possible treatment for astrocytomas , a type of brain tumour . Autism , depression , migraine headaches , polycystic ovary syndrome and diabetes mellitus type 2 have also been shown to improve in small case studies . There is evidence from uncontrolled clinical trials and studies in animal models that the ketogenic diet can provide symptomatic and disease @-@ modifying activity in a broad range of neurodegenerative disorders including amyotrophic lateral sclerosis , Alzheimer 's disease and Parkinson 's disease , and may be protective in traumatic brain injury and stroke . 
