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

Abstract

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.