Overweight teens are likely to put on even more weight as young adults, according to new study by the University of North Carolina.
Researchers studied 8,834 young people ages 12 to 21 for 13 years. They found that about half of the obese girls and one third of the boys gained 80 to 100 extra pounds by the age of 30.
Nutritionists say the extra pounds increase the risk of developing heart disease, diabetes and certain types of cancer.
"We were looking at adolescent weight status and how it relates to the development of severe obesity in adulthood because we're concerned that obesity and severe obesity have both increased over time, and during the period from teen to young adult, there's an increased risk for weight gain," the study's senior author, Penny Gordon-Larsen, an associate professor of nutrition at the Gillings School of Global Public Health at the University of North Carolina, Chapel Hill told Health Day.
"Our study demonstrated that obese adolescents are at risk for becoming severely obese in adulthood, and I think if people understand the risk of severe obesity, which is a lot of extra weight, they might be motivated to make changes. Teens might at least be motivated to maintain their current weight," she said.
Severe obesity -- defined as a body mass index above 40 -- heightens the risk for a number of health complications, including type 2 diabetes, high blood pressure, high cholesterol, asthma and arthritis. Other studies have estimated that obesity-related diseases could shorten a 20-year-old male's lifespan by 13 years and a woman's lifespan by eight years.
Gordon-Larsen and her colleagues reviewed data from the U.S. National Longitudinal Study of Adolescent Health on 8,834 people who were 12 to 21 years old in 1996. The study had two follow-up periods: the first from 2001 to 2002 and the second from 2007 to 2009.