March 5, 2004 (San Francisco) -- America's teens are growing up -- and out -- much faster than their parents, a phenomenon that increases their risk for heart disease, diabetes, and high blood pressure.
But researchers report that the dangerous effects of this super sizing of teens can be quickly reversed by diet and exercise.
Patricia Davis, MD, associate professor of neurology at the University of Iowa in Iowa City tells WebMD that she and her colleagues developed a good profile of today's teens by comparing their vital statistics to that of the teen's parents.
"Teens today are gaining weight twice as fast as their parents," Davis says.
Girls Gaining Faster Than Boys
The University of Iowa researchers studied 518 teens from 1971 to 1981. In 2001 to 2003, the researchers revisited those volunteers, who were now adults with teenage children of their own, and measured 228 of those children. "We found that body mass index (BMI), which is a measure of obesity, had increased significantly in boys and girls," Davis says.
In the earlier study the average BMI for boys was about 23 and for girls it was about 22, she says. In today's teens both boys and girls had an average BMI of about 24. So, not only are today's teens bigger, "but in the past men tended to be heavier. Now there is no difference," she says.
Julia Steinberger, MD, MS, associate professor pediatric cardiology, University of Minnesota in Minneapolis tells WebMD that Davis' findings should sound a warning to parents and physicians. Steinberger, who wasn't involved in the study, says, "This is an important message. If we're worried about children being overweight 20 years ago and we realized that was a bad thing, what we are seeing now is even more worrisome."
Increasing BMI Leads to Heart Risks
Davis, who presented her study results at the 44th annual American Heart Association conference on cardiovascular disease, epidemiology and prevention, says that along with the increases in BMI comes an increased link to other heart disease risk factors such as high blood pressure and high cholesterol.
So what changed between the 1970s and today? Davis says it is difficult to say for sure but several factors probably contribute to the problem, most notably poor diets -- especially increased reliance on fast foods -- and a sedentary lifestyle, with teens spending more time in cyber activities than in physical activities.
Healthy Diet, Exercise Work Fast!
James Barnard, PhD, professor of physiological science at the University of California, Los Angeles who presented another study at the AHA meeting, tells WebMD that teens can reverse the negative effects of bad diet and too little exercise and can do so very quickly.
To prove the point, Barnard and his colleagues enrolled 18 adolescents and their parents in either a six-day or 13-day residential, educational program at the Pritikin Longevity Center. During the program the 9- to 16-year-olds were put on a low-fat, high-fiber diet and they were required to participate in 2.5 hours of physical activity including cardiovascular workouts, swimming, and games such as volleyball.
In less than two weeks, "there was a 26% drop in total cholesterol, a 36% drop in LDL "bad" cholesterol and a 41% drop in triglygerides -- another blood fat. That tells us that American kids are eating a terrible diet," says Barnard. The Pritikin diet consisted of 15% to 20% calories from fat, more than 40 grams of fiber daily and less than 1600 milligrams of sodium.
Steinberger says Barnard's study is very encouraging.
Fast and Easy Results
"I think this is a wonderful study, especially since they were able to lower LDL and triglycerides without lowering HDL "good" cholesterol," she says. Steinberger, who wasn't involved in Barnard's study, says that some diet studies have suggested that restricting fat in diets can also lower HDL. In Barnard's study there was no significant change in HDL levels. "This is an excellent result and it demonstrates how easy -- and fast -- these results can be achieved," she says.
Asked if such a program is really easy or practical, Barnard tells WebMD, "if we can get these kids to take two weeks from summer vacation to do this, I don't think it would be difficult to implement in ordinary circumstances." The only barrier, says Barnard, is the willingness of "families and communities to get involved in the effort."