What Happens to Body Composition When Teens with AN Regain Weight?

As many studies have shown, when adult anorexics regain weight, they often add fat in the abdominal area, leading to truncal adiposity. A research team at Harvard sought to see if regional fat distribution in teens with AN compares with that in healthy teens and whether weight recovery among adolescents follows the same pattern as that among adults.

Dr. Madhusmita Misra and colleagues at Massachusetts General Hospital and Harvard Medical School followed 21 adolescent girls with AN and 21 control subjects matched for age and stage of puberty in a year-long study. Body composition was measured with dual-energy x-ray absorptiometry at baseline, then 6 and 12 months later (Am J Clin Nutr 2003;77:1361). “Weight recovery” was defined as at least a 10% increase in body mass index.

Weight regain did not lead to truncal obesity

At baseline, the girls with AN had a lower overall percentage of trunk fat than did the control subjects, but the percentage of extremity fat was not significantly different between the two groups. After weight gain, 13 of the 21 girls with AN had an increased percentage of truncal fat and an increased ratio of trunk fat to extremity fat, but this ratio was not different from that among healthy controls.

The authors concluded that unlike the previous findings in adults, the increases in truncal fat and in the ratios of truncal fat to extremity fat reported among the adolescent AN patients probably represent normalization of fat distribution rather than development of abdominal adiposity.