Teens with disordered eating behaviours gain BMI over time

Regardless of the type, disordered eating behaviours may lead to a higher body mass index (BMI) in the long run in adolescents, a recent study has shown.

Drawing from the Project Eating and Activity in Teens and Young Adults (EAT) study, researchers assessed disordered eating behaviours in 1,230 adolescents. Seven behaviours―importance of weight and shape, frequent dieting, extreme unhealthy weight control behaviours, overeating, distress about overeating, loss of control while overeating, and frequency of overeating―were included in the analysis and combined to create an overall behaviour score.

Crude models showed that at all time points, mean BMI was higher in females who had any disordered eating behaviour at baseline relative to their comparators without such behaviours. Adjustments for sociodemographic variables did not meaningfully alter these findings.

 At the first EAT wave, for example, females with disordered eating had a 0.9-kg/m² greater BMI. This remained stable over time, with the between-group difference even growing to 1.6, 1.8 and 2.7 kg/m² at the second, third and fourth EAT waves, respectively.

The same was true in males. At the first EAT wave, those with disordered eating behaviours had BMI greater by 1.5 kg/m² than their counterparts. This persisted over time, with BMI difference values of 1.7, 1.7 and 1.3 kg/m² at the second, third and fourth waves, respectively.

In both males and females, distress about overeating and overeating with loss of control were the individual behaviours that best explained the differential BMI.