News & Research

By: Felicia Breedy

A study by ADA-funded researcher Lisa Martin, PhD and colleagues, found that teenager’s weight and body mass index (BMI) tends to stay the same throughout adolescence.

The researchers explained that they expected both weight and BMI to increase during adolescence, and they found this to be true for the lean adolescents in their study. However, most of the teens under investigation did not show unexpectedly large accumulations of excess weight and, therefore, did not experience increases in risk of developing overweight.

About 18 percent of the 1,746 teens studied were overweight at the beginning of the study, and about 19 percent were at risk of becoming overweight based on their BMI percentile. Dr. Martin, and colleague Jessica Woo, PhD, explain that at the end of the four-year study, the same percentage of teens were overweight or at risk for overweight.  Many, but not all, of the same individuals were represented in the overweight categories in follow-up years.  "There was some shifting across categories," states Dr. Woo, "but it was relatively minor, and does not result in a net shift upward."

Although overall BMI did not change for the group of adolescents studied, researchers did notice that the leanest teens, especially girls, tended to gain the most weight and have the greatest increase in BMI over three years of follow-up. Even though their BMI still fell into the “normal” range, the increase was more than researchers expected for age- and sex-related growth. Nonetheless, this group serves as an exception among the individuals under investigation.

In an interview with Reuters Health, author Jessica Woo, PhD, at Cincinnati Children’s Hospital in Ohio, explained that because weight tends to remain stable in most adolescents it may be best to focus obesity-prevention efforts on younger children. If weight can be controlled prior to the teenage years, there may be a greater chance of maintaining a healthy BMI through adolescence.

(Crimmins NA, Dolan LM, Martin LJ, et al:  Stability of adolescent body mass index during three years of follow-up.  Journal of Pediatrics.  151(4)383-87, 2007.)