The outcome for patients attempting dietary therapy for epilepsy a second time is unknown. Twenty-six subjects treated with the ketogenic diet as children who then began either the ketogenic diet or a Modified Atkins Diet (MAD) at least 6 months later were evaluated. The mean age at the first diet trial was 5.6 years and at the second diet trial was 11.5 years. Most restarted dietary therapy because of persistent seizures (65%) or recurrence after seizure freedom (19%). Overall, 77% had a ≥50% seizure reduction with the first diet, and 50% with the second diet, P = .04. Individual subject responses were largely similar, with 14 (54%) having identical seizure reduction both times, 9 worse (35%) with the second attempt, and 3 (16%) improved. The second diet trial was more likely to lead to >50% seizure reduction if the first trial was started at a later age (7.4 vs 3.9 years, P = .04).