Critical Nutrients in the Ketogenic Diet for Adolescents Based on Optimized Hypothetical Meal Plans

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.