To evaluate the efficacy of ketogenic diets (KD) treatment for adults with intractable epilepsy and patients’compliance for KD treatment by systematic review. Methods: PubMed, Web of Science, Embase, and the Cochrane Library were systematically searched for RCT studies in adults published up to February 2022. After data extraction and quality evaluation of the studies independently by two researchers, meta-analysis was performed on the included studies using RevMan software. Results: A total of 4 RCTs were included, 3 of which evaluated KD versus conventional diet, with a total of 221 cases. Another study compared different KD and included 80 cases. The results showed that the meta-analysis supported the KD group, in terms of the effective rate of 50% or more reduction in seizure frequency, but the difference was not statistically significant. Considering the heterogeneity, only two studies (Zare 2017 and Kishk 2021) were included, and the effective rate was 48.65%, with the difference being statistically significant. The loss-to-follow meta-analysis showed that the results were more supportive of a regular diet, but the difference was not statistically significant. Supplementation of the Modified Atkins Diet (MAD) in the first month with a ketogenic formula resulted in lower loss to follow-up and better compliance than MAD alone. Conclusion: KD is a promising complementary therapy for adults with intractable epilepsy and is well tolerated.