Peer reviewed / Manuscript (original) submitted: 19 December 2025; revision accepted: 25 February 2026
Introduction
A ketogenic diet (KD) is a high-fat, very-low-carbohydrate diet [1]. In classical KDs, the ketogenic ratio, i.e., the ratio of fat to carbohydrates plus protein, is defined. Traditionally, classical KDs employ ketogenic ratios of 3:1 or 4:1, resulting in approximately 87–90% of total energy intake being provided fat [2]. There are various forms of KD that can be used in nutrition therapy, each with different macronutrient ratios of fat, protein, and carbohydrates and varying degrees of restrictiveness [1, 2]. Currently, there are four major dietary approaches to ketogenic diets: the Classic Ketogenic Diet (CKD), the Modified Atkins Diet (MAD), the Medium-Chain Triglyceride Ketogenic Diet (MCT-KD), and Low-Glycemic Index Treatment (LGIT) [3].
According to the S1 guideline, the main indication for a KD is drug-resistant epilepsy and epilepsy that is difficult to treat in children and adolescents. KDs are also increasingly being used in adults with drug-resistant epilepsy [4]. The rationale is that KDs can reduce the frequency and severity of seizures [1] and can lead to a > 90% reduction in seizures [5]. KD therapy is also the first-line treatment for glucose transporter 1 (GLUT1) deficiency and pyruvate dehydrogenase (PDH) deficiency [4]. Regardless of the dietary approach and the medical indication, ketogenic diets are very restrictive and time-consuming nutrition therapy interventions. It is therefore not surprising that common reasons for low adherence include a limiting effect on everyday life, difficulty preparing meals, and a resulting lack of motivation [6]. With this in mind, commercially available ketogenic replacement products (KRPs) may prove beneficial in the case of KDs [7]. Although not essential for implementing the diet, these products may facilitate its practical application for patients and their families [8]. …
Abstract
Ketogenic diets (KD) are a treatment option for drug-resistant epilepsy and certain metabolic disorders, recommended by clinical guidelines. The strict carbohydrate restriction and high fat content of these diets can result in a risk of inadequate micronutrient intake. Commercially available ketogenic relacement products (KRPs) can make implementation easier and have an effect on micronutrient supply. Optimized 3-day meal plans were developed for ten age groups using ketogenic ratios of 1:1, 2:1, and 3:1, and were analyzed for their micronutrient content. The estimated intake levels were compared with the German Nutrition Society (DGE)/Austrian Nutrition Society (ÖGE) reference values, with deviations of more than five percent being classified as potentially critical. With the 1:1 ratio, 24 out of 26 nutrients reached at least 95% of the reference values in the children and adolescents (Ch/Ado) group, and 22 out of 26 nutrients reached this threshold in the Adu group. For the 2:1 ratio, 20 (Ch/Ado) and 21 (Adu) out of 26 nutrients reached the 95% threshold. In the case of the most restrictive ratio of 3:1, 17 out of 26 nutrients in both age groups fell within the defined target range. Nutrients that were more frequently found to fall below reference values, depending on the ratio and age group, included vitamin D, vitamin B1, vitamin B12, pantothenic acid, potassium, zinc, iron, and fluoride. Overall, it was found that even when using commercially available KRPs, nutritional requirements were not fully met, and the number of potentially critical nutrients increased with greater dietary restriction. It can therefore be concluded that targeted supplementation is necessary in this context, with the extent of required supplementation depending on the ratio and age group.
