UNLABELLED: The ketogenic diet (KD), containing high levels of fat and low levels of carbohydrates, has been used to treat refractory epilepsy since the 1920s. In the past few decades, there has been more interest in less restrictive KDs such as the modified Atkins diet (MAD). PURPOSE: Our aim was to review all evidence regarding the efficacy and tolerability of the KD and MAD from randomized controlled trials (RCTs) in children and adolescents with refractory epilepsy. METHODS: We reviewed the current literature using Cochrane, EMBASE, and MEDLINE (using PubMed). We implemented predefined criteria regarding dataextraction and study quality. RESULTS: We identified five RCTs that generated seven publications and recruited 472 children and adolescents with refractory epilepsy (≤ 18 years). The primary outcome (seizure frequency reduction (SFR) ≥ 50%) was attained in 35-56.1% of the participants in the intervention group, compared with 6-18.2% in the control group. Our meta-analysis underlined the significant efficacy of the KD compared with the control group: RR = 5.1 (95% CI 3.18-8.21, p < 0.001). Additionally, only two studies mentioned possible biomarkers to objectively evaluate the efficacy. Secondary outcomes, such as seizure severity and quality of life, were studied in three trials, leading to indecisive generalization of these findings. Gastro-intestinal adverse effects were the most prevalent, and no severe adverse effects were reported. CONCLUSION: Despite the heterogeneity between all studies, the beneficial results underline that dietary interventions should be considered for children and adolescents with refractory epilepsy who are not eligible for epilepsy surgery. Future studies should be multi-center and long-term, and evaluate potential biomarkers and adverse effects.