A randomized, crossover comparison of daily carbohydrate limits using the modified Atkins diet Eric H. Kossoff a, * , Zahava Turner a , Renee M. Bluml b , Paula L. Pyzik a , Eileen P.G. Vining a a The Pediatric Epilepsy Center, Departments of Neurology and Pediatrics, Johns Hopkins Medical Institutions, Baltimore, MD, USA b Department of Pediatrics, Children’s Hospital of Los Angeles, Los Angeles, CA, USA Received 15 December 2006; revised 23 January 2007; accepted 24 January 2007 Available online 26 February 2007 Abstract The modified Atkins diet is a dietary therapy for intractable epilepsy that mimics the ketogenic diet, yet does not restrict protein, calories, and fluids. The ideal starting carbohydrate limit is unknown. Twenty children with intractable epilepsy were randomized to either 10 or 20 g of carbohydrates per day for the initial 3 months of the modified Atkins diet, and then crossed over to the opposite amount. A significantly higher likelihood of >50% seizure reduction was noted for children started on 10 g of carbohydrate per day at 3 months: 60% versus 10% (P = 0.03). Most parents reported no change in seizure frequency or ketosis between groups, but improved tolerability with 20 g per day. A starting carbohydrate limit of 10 g per day for children starting the modified Atkins diet may be ideal, with a planned increase to a more tolerable 20 g per day after 3 months. Ó 2007 Elsevier Inc. All rights reserved. Keywords: Atkins diet; Ketogenic; Carbohydrates; Intractable; Epilepsy; Children 1. Introduction The modified Atkins diet is a nonpharmacologic therapy for intractable childhood epilepsy that was designed to be a less restrictive alternative to the traditional ketogenic diet [1,2]. This diet is started as an outpatient without a fast, allows unlimited protein and fat, and does not restrict calories or flu- ids. Early studies have demonstrated efficacy and safety [1,2]. As clinicians use this diet, a major unanswered question concerns the ideal starting daily carbohydrate limit. In chil- dren receiving the traditional ketogenic diet, carbohydrates are restricted to approximately 5–10 g per day; therefore, our modified Atkins diet used this limited amount [3]. How- ever, 10 (50%) of 20 children in our prospective study increased carbohydrates to 15 g per day after the first month, and one child increased to 20 g per day after the fourth month [2]. Only one of these children reported a reduction in efficacy as a result, and none described decreased levels of urinary ketosis. In a study of a low-glycemic-index dietary treatment, carbohydrates were even less restricted, with efficacy noted at 40–100 g of low-glycemic-index carbohydrates per day, despite the majority having nearly no urinary ketosis [4]. This study was designed to identify the ideal starting limit of carbohydrates on the modified Atkins diet to max- imize efficacy, ketosis, and tolerability. A crossover design was employed to evaluate carbohydrate amounts for both the overall population response and each individual child. In addition, we attempted to clarify typical calorie, fat, and protein compositions of children receiving the diet. 2. Method A prospective, randomized, crossover study design was employed. The parents of the 20 children with epilepsy consented after an initial evalua- tion of their children in the Johns Hopkins Hospital outpatient pediatric epilepsy clinic by the primary investigator (E.K.). The study was approved by the Johns Hopkins institutional review board. 1525-5050/$ - see front matter Ó 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.yebeh.2007.01.012 * Corresponding author. Address: The Johns Hopkins Hospital, Suite 2158, 200 North Wolfe Street, Baltimore, MD 21287, USA. Fax: +1 410 614 2297. E-mail address: ekossoff@jhmi.edu (E.H. Kossoff). www.elsevier.com/locate/yebeh Epilepsy & Behavior 10 (2007) 432–436