Analysis of critical nutrients in ketogenic diets for adults based on optimized hypothetical meal plans.

INTRODUCTION: Ketogenic diets are used in various clinical and non-clinical contexts in adults. Due to the high degree of restriction in certain ketogenic diet variations, there is a potential risk of insufficient micronutrient intake and systematic analyses of nutrient supply in adults remain sparse. METHODS: Optimized, hypothetical daily ketogenic meal plans were created for adults aged 19 to over 65 years, with ketogenic ratios of 3:1, 2:1, and 1:1. The analysis was carried out separately for four age groups. Nutrient calculations were based on the German Nutrient Database using the PRODI® nutrition software (Nutri-Science GmbH, Germany). The calculated micronutrient intakes were compared with age-related national reference values for each age group. Supply < 95% was considered as potentially critical. RESULTS: Relevant deficiencies were observed in all age groups, particularly in fiber, vitamin D, several B vitamins, potassium, zinc and fluoride. As restrictiveness decreased, intake levels improved, with the 1:1 ratio showing the highest overall micronutrient density. Regardless of the ratio, vitamin D, fiber and fluoride remained potentially critical in all age groups. CONCLUSION: Strict ketogenic ratios carry a high risk of micronutrient deficiencies. Although liberal ratios improve supply, there are still structural nutrient restrictions. Therefore, careful food selection and nutritional therapy support remain essential.