Effects of the ketogenic diet on nutritional status, resting energy expenditure, and substrate oxidation in patients with medically refractory epilepsy: A 6-month prospective observational study

Background & aims: This 6-month prospective, single-arm observational study was designed to assess the effects of the KD on the nutritional status, resting energy expenditure (REE), and substrate oxidation in patients with drug-resistant epilepsy. Methods: Eighteen patients with medically refractory epilepsy underwent assessment of body composition, REE, and substrate oxidation rates before and after 6 months of MD. Results: Compared with baseline, there were no statistically significant differences at 6 months in terms of height, weight, BMI z-scores, and REE. However, the respiratory quotient decreased significantly (from 0.80 +/- 0.06 to 0.72 +/- 0.05,p < 0.001) whereas fat oxidation was significantly increased (from 50.9 +/- 25.2 mg/min to 97.5 +/- 25.7 mg/min, p < 0.001). Interestingly, we found that the increase in fat oxidation was the main independent predictor of the reduction in seizure frequency (beta = -0.97, t = -6.3, p < 0.05). Conclusions: Administering a MD for 6 months in patients with medically refractory epilepsy increases fat oxidation and decreases the respiratory quotient, without appreciable changes in REE. (C) 2011 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.