TUESDAY, Nov. 9, 2010 (HealthDay News) -- Obese teenagers are 16 times more likely to become severely obese adults than teens of normal weight, new research finds.
Someone who is severely obese is about 100 pounds or more above their ideal body weight, according to 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.
"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," explained Gordon-Larsen.
"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.
Results of the study are published in the Nov. 10 issue of the Journal of the American Medical Association.
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. In addition, people who are severely obese can expect significant reductions in life expectancy, according to background information in the study.
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.
At the start of the study, 79 teens (about 1 percent) were considered severely obese. By 2009, 60 of those people (70.5 percent) were still severely obese in adulthood, the investigators found.
Also by 2009, an additional 7.9 percent of those who hadn't been severely obese as teens were now classified as severely obese adults. Black women were the most likely to become severely obese as adults, reported the study.
Teens who were obese at the beginning of the study were 16 times more likely to become severely obese adults compared to normal-weight or overweight teens.
"This is really setting these kids up to have significant health challenges later in life," said Gordon-Larsen.
"We need to try to intervene and prevent obesity early in life, and if we have an obese adolescent, we really need to work to prevent severe obesity," she said.
"I wasn't especially surprised by the study's findings. Other research has also shown that weight during adolescence is very predictive of weight in adulthood," said Dr. Goutham Rao, clinical director of the Weight Management and Wellness Center at Children's Hospital of Pittsburgh.
And getting teenagers to change their habits may be difficult, he noted. "If you have a 3-year-old, it's relatively easy to influence that child's eating habits because you provide all the food. With adolescents, it's much more complicated because they're often making their own food and drink choices and their habits are more entrenched," he said.
But parents still provide the bulk of food in a teen's diet and can set up a healthy food environment at home by not providing sweetened beverages and making healthy snacks, like fruits and vegetables, available, he added.
Other important tips, he said, are to limit fast-food consumption to no more than once a week, limit screen time to two hours a day, and to encourage some exercise every day. It's also important to try to have at least one parent eat dinner with your teenager most days of the week.
One bright note in this study was that about 30 percent of severely obese teens didn't go on to become severely obese adults, suggesting that it is possible to change even entrenched lifestyle habits.
And "the younger they are, the more chances you have to make changes," added Rao.
The Weight-control Information Network has information for teens on healthy lifestyle habits.