At a time when Americans revere the super-sized combo meal and children spend hours glued to televisions or computers instead of playing outdoors, researchers and health officials are seeking strategies to curb an epidemic of childhood obesity.
An estimated 10% to 15% of American kids are seriously overweight, a near doubling over the last two decades, federal figures show. As many as 25% are at risk for obesity and many already show biochemical changes such as elevated cholesterol and blood pressure that are precursors to obesity-linked illnesses.
Increasing numbers are even being diagnosed with maladies that weren't thought to strike until the grown-up years, such as so-called adult-onset, or type 2, diabetes. As these children age, heart disease and diabetic complications like kidney failure loom.
"As this wave of obesity moves into adulthood, we're going to be seeing greater health costs associated with [it]," said Dr. William H. Dietz, director of the Division of Nutrition and Physical Activity at the federal Centers for Disease Control and Prevention in Atlanta. "It's crucial we develop effective prevention programs as well as effective treatment for the 10% to 15% that are already overweight."
Most doctors define obesity in children as being at or above the 95th percentile for weight based on height and gender. They become concerned at the 85th percentile, especially if children already show warning signs of illness.
Although genetics plays a role in susceptibility to obesity, it's environment that determines whether many children will put on extra pounds. So researchers are trying to understand not only kids' relationship to food, but how the home, the school cafeteria, class curriculum and popular culture drive eating behavior--and what could be used to combat obesity.
"If there were a magic bullet, we would have done it a long time ago," said Eileen Kennedy, a deputy undersecretary at the U.S. Department of Agriculture, who is responsible for the new Behavioral Nutrition Research Initiative.
As part of that initiative, the department has made obesity research a priority and has conducted several conferences to identify possible solutions. At a recent USDA-sponsored meeting in New Orleans, nutritionists, pediatricians, psychologists and government health officials began identifying studies that could help shape public policy.
Some researchers have pinpointed risk periods in a child's life that could become target times for stepping in with prevention or treatment. One is the so-called period of adiposity rebound--the point when a young child's body fat increases after several years of decline, usually around age 5 or 6; a 1998 study found that if they reach that point before their fifth birthday, the child is twice as likely to be an obese adult. The other key time is adolescence, when hormones kick in.
This year, the CDC has almost $5 million to help develop obesity interventions for children and adults. About half will go to states for local projects; the remainder will underwrite research into links between behavior and obesity to help health officials figure out where they can make a difference.
Although obesity crosses ethnic, racial and economic lines, it disproportionately strikes Native Americans, African Americans and Hispanic Americans, said Dr. Francine R. Kaufman, head of endocrinology at Childrens Hospital Los Angeles. "Our minority children particularly are living in poverty and are much more prone. The real behavioral issue is they're not going off and getting fresh jicama. They're going to McDonald's."
Many of the innovations explored in recent years have targeted lower-income and minority kids.
Among researchers reaching out to those populations is Dr. Thomas N. Robinson, a Stanford University pediatrics professor, who has just begun developing a federally funded program for 8- to 10-year-old African American girls. It will probably incorporate traditional African dancing and education about their African heritage to make exercise more enticing and relevant to their lives. Similar programs might use other types of dance because it's an appealing way to get youngsters burning calories.
Reasons for Weight Gain
Putting on excess pounds is a matter of taking in more calories than the body uses and converting them to fat. Successful bulge-battling involves increasing activity and decreasing caloric intake.
That may sound simple, but it's not.
Humans have become an increasingly sedentary species. They were evolutionarily built to store fat to survive during famine, said Michael Goran, a visiting professor at USC's Institute for Prevention Research. "Right now we have an abundance of low-quality, high-calorie food and an environment and lifestyle that requires less physical activity. We're storing energy, but there ain't no famine."