When did pediatric obesity become such a problem?
For scientists, the alarms went off in the 1980s and 1990s. Before then, experts took comfort in data from the 1960s indicating that just 5 percent of children and adolescents had obesity. It just did not seem like a pressing issue.
But national data in the 1980s showed that the rate had doubled. By 2000, it had tripled, and by 2018, quadrupled. As the epidemic began, expert opinions about why it was happening circulated widely, often citing favorite villains like Big Food, too little exercise or a lack of fresh fruits and vegetables. But rigorous evidence was scarce and solutions evasive.
Didn’t anyone try to do intervention studies?
Yes, but results were disappointing. In the 1990s, for example, the National Institutes of Health sponsored two large, rigorous studies. The researchers asked whether weight gain in children could be prevented by intervening in schools by expanding physical education, offering more nutritious cafeteria meals, teaching students about proper eating habits and the need to exercise, and involving parents.
One study, an eight-year, $20 million project sponsored by the National Heart, Lung and Blood Institute, followed 1,704 third graders in 41 elementary schools in the Southwest. Students there were mostly Native Americans, a group at high risk for obesity.
The schools were divided into two groups. Some schools got intensive intervention, while others were left alone. Researchers determined, beginning in fifth grade, whether the children in the intervention schools were weighing less than those in the other schools.
Sadly, they were not, although the students were deeply familiar with the importance of activity and proper nutrition. The children who got intensive treatment also ate less fat, going from 34 percent to 27 percent in the total diet.
“It was not enough to change body weight,” said Benjamin Caballero of the Johns Hopkins Bloomberg School of Public Health, the study’s principal investigator.