Background: After being developed in the 1920s, the ketogenic diet fell into disuse, only to make a comeback at the end of the 20th century. In addition to its original use in the treatment of epilepsy, research on the ketogenic diet is now focusing on many other indications. Methods: Based on a systematic literature analysis according to the PRISMA guidelines, an overview of the current research on specific topics in the last five years (2019 to August 2024) was compiled. Results: A total of 290 trials were included. In total, 32 topics were analyzed, most of which were related to overweight and obesity, as well as exercise and epilepsy. The articles included 1981 authors from 47 countries, who published their results from intervention and observational studies in 153 journals. In total, 227 studies lasted less than six months, while 61 studies lasted more than six months. Conclusions: The results and the increasing amount of research underline the growing scientific attention and potential of the ketogenic diet to offer new therapeutic and individual preventive approaches. These trends indicate that the ketogenic diet remains an important international research topic.

Background: Ketogenic diets can treat drug-resistant epilepsy, even in early childhood. However, due to the severely restricted food selection, there is an assumed increased risk of inadequate micronutrient intake. Currently, the available data is limited. Methodology: Optimized daily meal plans were created for infants and children aged 1–9 years (physical activity level; PAL 1.6) in three ketogenic ratios (3:1, 2:1, 1:1). Compliance with reference values for micronutrients (≥95%) was analyzed using the reference values of the German and Austrian Nutrition Societies (DGE/ÖGE) and PRODI^® nutrition software (Germany). Results: Vitamin D never reached more than 25% of the reference values in any age group or ratio, and pantothenic acid consistently remained at around 40–70%. At the 3:1 and 2:1 ratios, the mean values for vitamins B₁, B₂, and B₁₂, as well as for calcium, zinc, iron, and fiber, were all below 95% of the reference values. Although the 1:1 ketogenic ratio was more nutrient-dense, this only partially compensated for potential deficiencies. Conclusions: The results illustrate a limited micronutrient supply dependent on the ratio in ketogenic diets for infants and children. Careful food selection and nutritional therapy support are necessary to avoid potential nutrient gaps.

Background: Ketogenic diets are used as a non-pharmacological treatment for drug-resistant epilepsy in childhood and adolescence. However, the potential micronutrient deficiencies associated with ketogenic diets have not been adequately investigated in vulnerable groups, such as children and adolescents, and detailed dietary analyses are lacking. Methodology: Optimized ketogenic daily meal plans were created for adolescents aged 10–18 years with different ketogenic ratios of 3:1, 2:1, and 1:1. Micronutrient supply was calculated using PRODI^® nutrition software (version 7.3, Nutri-Science GmbH, Freiburg, Germany), based on the German Nutrient Database and compared with DGE/ÖGE reference values. Nutrients below 95% of the reference values were classified as potentially critical. Results: The results showed that micronutrient density decreased with increasing dietary restriction. Vitamin D and fiber were below reference values for all ratios and age groups. The 3:1 ratio exhibited deficiencies in potassium, zinc, fluoride, and several B vitamins. Overall, the 1:1 ratio provided the most favorable nutrient coverage, though vitamin B₁ and fluoride remained insufficient. The results indicate that potentially critical micronutrients are highly sensitive to ketogenic ratios in adolescents. Conclusions: This analysis enables the identification of relevant nutrients to be more targeted, suggesting that a one-size-fits-all approach of supplementation should be replaced by options differentiated by age and dietary restrictions.