Heavy teenagers are often destined for skyrocketing weight gain in their 20s, a new study shows.

About half of obese teenage girls and about a third of obese teen boys become severely obese by the time they are 30 — meaning they are 80 to 100 pounds over a healthy weight, the new research says.

Other research has found that heavy children are more likely to become heavy adults. But this is one of the first studies to show what happens to teens who are obese — that is roughly 30 or more pounds over a healthy weight — as they reach adulthood.

Among the study's findings, reported in Wednesday's Journal of the American Medical Association:

•About three-quarters of severely obese teens remained that heavy at age 30.

•Only 1%-2% of normal-weight teens became severely obese by the time they were 30.

•Normal-weight adolescents gained an average of 37 pounds from their teen years to age 30. Their average height was 5-foot-7.

Source: USA Today