Anorexia Nervosa: Charting Patterns of Weight Regain

Regaining weight is the number-one goal for clinicians who treat patients with anorexia nervosa. Until recently, however, relatively little was know about how anorectic patients adapt to increasing weight gain and how the relative distribution of body fat is affected during spontaneous weight recovery (see also article on page 1).

Dr. Steven Grinspoon and coworkers at Harvard Medical School and Massachusetts General Hospital recently reported that in women with anorexia nervosa, spontaneous weight gain leads to a significant increase in trunk adiposity. An additional findings was that administration of estrogen may not protect against accumulation of central fat (Am J Clin Nutr 2001; 73:865). In their study, the gain in central fat occurred even though weight recovery was incomplete and the subjects were still at a very low weight.

A role for cortisol

Another notable finding was that truncal fat accumulation was greatest in women with the largest increases in urinary free cortisol concentrations (20% of patients in this study had increased urinary cortisol excretion). Therefore, according to the authors, one explanation for the pattern of fat deposits might be that initial weight gain among patients with hypercortisolemia may predispose them to greater accumulation of fat in the abdomen.

Twenty-seven amenorrheic women (mean age: 26 years) were identified through an outpatient bone loss study and were randomly assigned to receive or not receive estrogen without any dietary intervention other than calcium and multivitamin supplements. Body composition was measured at the beginning of the study, then at 6 and 9 months, and was compared with values obtained from 20 healthy, eumenorrheic, age-matched control subjects.

Twenty of the 27 patients with anorexia nervosa spontaneously gained weight over the 9 months (mean gain: 4.1 kg), and the mean body mass index among anorectic patients increased from 16.1 to 17.5. Fat mass and lean mass accounted for 68% and 32% of the gain in total body mass, respectively. With spontaneous weight gain, there was a significant increase in the percentage of truncal fat—from 32.4% at baseline to 36.5% at 9 months.

The mechanisms responsible for the accumulation of abdominal fat relative to extremity fat during weight gain are unknown. One potential mechanism is that weight gain in the first phase of weight recovery in anorectic patients occurs because of relative estrogen deficiency, which may help contribute to changes in fat distribution. Many studies suggest that estrogen administration affects regional and whole-body composition in estrogen-deficient women. In this study, however, this was not the case.