Exercise, Diet Aid Youthful Obesity
By Amanda Gardner, HealthDay Reporter
FRIDAY, April 29 (HealthDay News) -- There may be hope yet for the growing number of obese American youngsters and for the adults they will become.
New studies are reporting some success with dietary and exercise interventions, both in reducing body mass index (BMI) and in ameliorating risk factors associated with heart disease.
The studies were presented Friday at the American Heart Association's annual conference on cardiovascular disease epidemiology and prevention in Washington, D.C.
One study found that a rigorous diet-and-exercise program reduced risk factors for atherosclerosis in teenagers in as little as two weeks.
Studies have indicated that atherosclerosis, or hardening of the arteries, may begin as early as the first 10 years of life. The researchers wanted to see if they could affect markers for atherosclerosis development during childhood.
The study involved 20 obese teenagers who were enrolled in the Pritikin two-week residential program, put on a high-fiber, low-fat, low-cholesterol diet, and asked to do two to three hours of daily aerobic exercise, such as beach volleyball, swimming and tennis.
"The exercise component was designed to get subjects to move around and not necessarily to become tri-athletes," said study author Andrew K. Chen, who is with the University of California, Los Angeles.
Following the two-week program, the teens' total cholesterol fell by 21 percent, LDL or "bad" cholesterol fell by 25 percent, and triglycerides were reduced by 39 percent.
The researchers also found decreases in measures of oxidative stress, which can lead to atherosclerotic plaques, as well as reductions in BMI and inflammatory markers.
Chen hypothesized that most of the benefits were derived from the dietary component, which was designed to combat oxidation.
"Levels of risk factors for atherosclerosis were as high as those found in adult subjects [at the start of the study], and we were able to reduce the magnitude of risk factors quite significantly in a relatively short period of time," he said.
A second study found that a full-service, medically supervised program resulted in improved food choices and more physical activity for kids.
"All adults were once children, and we know that obese children will, in many cases, lead to obese adults," said study author Dr. William N. Evans, of the Children's Heart Center in Las Vegas. "We think that treatment of childhood obesity, hopefully, will result in the prevention of coronary artery disease in adults. We looked at the treatment side in children as the prevention side in adults."
Evans and his colleagues developed a multi-disciplinary, "one-stop shopping" medical model where everything was located in one place: exercise physiologists, dieticians, psychological counselors, doctors and support staff.
"It's not simply 'go home, eat less, exercise more'," Evans said. The dietary and exercise strategies in the study were tailored for each of the 70 children and their families.
After three months, Evans saw improvements in all the kids in the study.
"We found that there were statistically significant changes for the better in what you do and what you eat," he said.
At the start of the program, 70 percent of parents reported that their children were watching at least four hours of television a day. By the end of the program, that number fell to about 40 percent.
Again, at the beginning of the study, about 40 percent of kids were felt to be less active than peers; by the end, 80 percent were felt by their parents to be more active than their peers.
Vegetable consumption also rose: from 40 percent of participants having two servings a day to about 65 percent.
"These are short-term results," Evans said. "Our long-term goals are to collect data over a long period of time to see if positive changes can be sustained."
A third study looked at the really big picture of health, finding that people in general exercised less in extreme hot or cold temperatures (below 25 degrees or above 85 degrees).
People living in more temperate climates also tended to have better BMI, reported study author Ge Lin, of Baylor College of Medicine, in Houston.
"It's like, 'Houston, we have a problem,'" Lin said. "What's the problem? It's too hot to go outside."
Although the weather can't be changed, it might be possible to incorporate environmental amenities in different communities so that people are more active, Lin suggested.
More information
The U.S. Centers for Disease Control and Prevention (www.cdc.gov ) has more on childhood obesity. 
SOURCES: April 29, 2005, American Heart Association news conference with Andrew K. Chen, B.A., University of California, Los Angeles; Ge Lin, Ph.D., Baylor College of Medicine, Houston; William N. Evans, M.D., Children's Heart Center, Las Vegas, and University of Nevada School of Medicine
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