A major goal in treating anorexic patients is correcting malnutrition by means of refeeding. In women with anorexia nervosa (AN), however, great differences between predicted and measured values of resting energy expenditure (REE) have been found. Little is known about the changes that occur during refeeding, but it is possible that these changes contribute to the difficulty of weight gain among AN patients.
An increase in physical activity with refeeding is expected in AN patients, who are known to engage in physical hyperactivity so as not to put on weight. In addition, there is not a lot of information about the effect of psychological factors, such as mood changes on REE during refeeding. Furthermore, energy metabolism can be severely changed by smoking, dieting or exercising. Therefore, some French researchers set out to identify the factors associated with the increase in REE during refeeding of AN patients.
Eighty-seven malnourished AN patients and 48 healthy, non-anorexic patients with the same characteristics were included in this study. The AN patients were hospitalized for tube feeding and renutrition for > 2 months. Before and 8, 30, and 45 days after the beginning of refeeding, REE was measured by indirect calorimetry. Energy intake (EI), physical activity, body composition via bioelectrical impedance, smoking behavior, abdominal pain, anxiety, depressive mood, serum thyrotropin and thyroid hormone, and urinary catecholamines were also measured. The same were also measured in 52 patients after 75 days of refeeding and in 18 patients after 1 year of complete recovery (defined as stable and normal BMI, normal El, disappearance of fear of eating and of becoming fat, and normal eating behavior at the 1-year visit, without relapse in the previous two months).
After one week ofrefeeding, total EI reached a mean of 2.5 times the initial intake and REE increased from 3.84 to 4.36 MJ/day. The 13.4% increase of REE was significantly greater than that expected on the basis of the increase in fat-free mass (FFM: 1.6%). The ratio of REE to FFM remained high and was significantly related to four factors: energy intake, anxiety, abdominal pain and depressive mood. The ratio also increased significantly with physical activity and cigarette smoking. The rise in REE related to the above factors leveled off after recavery from AN.
The data showed the role of factors such as anxiety, smoking, and activity level in the increased REE in AN patients. This knowledge should be used in conjunction with others in the tricky process of refeeding AN patients.
Virginie Van Wymelbeke, Laurent Brondel, Jean Marcel Brun and Daniel Rigaud, Factors associated with the increase in resting energy rxpenditure during refeeding in malnourished anorexia nervosa patients, Am J Clin Nutr 80: 1469-1477 (December 2004) [Address reprint requests and correspondence to D Rigaud, Service d'Endocrinologie, CHU Le Bocage, 21 079 Dijon Cedex, France. E-mail: Daniel.firstname.lastname@example.org.]
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