Altered energy metabolism in anorexia nervosa

Optimal nutritional rehabilitation of anorexia nervosa requires more inform ation concerning actual energy and substrate requirements. To this end, ind irect calorimetry was performed in female patients (n=34, age 20.9+/-1.2 yr , body mass index [BMI] 15.6+/-0.2 kg/m(2); mean+/-SEM) soon after commence ment of refeeding and at the time of discharge from hospital (n=18, BMI 19. 0+/-0.3 kg/m(2)). Healthy female controls (n=18, age 24.6+/-1.3 yr, BMI 21. 6+/-0.6 kg/m(2)) were also tested. Resting energy expenditure (REE) and res piratory quotient (RQ) were measured in the fasting state, followed by diet -induced thermogenesis (DIT) and RQ over a 4 h period following a 100 g ora l glucose load. Compared with post-refeeding patients and controls, pre- re feeding patients had a high basal RQ and a low REE, with a paradoxically hi gher DIT (13.2+/-0.9% of REE vs 8.3+/-1.2% and 8.6+/-0.9% in post-refeeding patients and controls, respectively). RQ values in pre-refeeding patients exceeded unity following the glucose load, probably reflecting net lipogene sis, whereas in the post-refeeding patients, post-glucose RQ was similar to that of controls, suggesting premature curtailment of lipogenesis. These d ata demonstrate energy wasting in emaciated patients with anorexia nervosa. Biological repair processes could account for disproportionate energy loss early in refeeding and there may be some later impediment to full restorat ion of fat stores. (C) 2000 Elsevier Science Ltd. All rights reserved.