A review focused on the role of ketogenic diets in neurodegenerative diseases (including PD) was published in the MDPI journal Nutrient in 2019. The goal of the review was to assess the effectiveness of ketogenic diets as part of therapy for neurodegenerative diseases. In PD, dopaminergic neurons in the substantia nigra are affected by a degeneration process leading to motor and non-motor disturbances. The available results of research projects dealing with the use of the KD and ketone bodies in neurodegenerative diseases are fairly promising. At the same time, the majority of studies reviewed were employed in vitro or by using animal models. The number of studies with human participation is rather small, and those that exist feature relatively short therapy duration periods.