When did childhood obesity become such a problem?
Alarm bells went off for scientists in the 1980s and 1990s. Before then, experts took solace in data from the 1960s, which showed that only 5 percent of children and adolescents were obese. It just didn’t seem like an urgent problem.
But national data in the 1980s it was found that the rate had doubled. By 2000 it had tripled and by 2018 it had quadrupled. When the epidemic began, expert opinions about why it happened circulated widely, often citing favorite villains like Big Food, lack of exercise, or a lack of fresh fruits and vegetables. But rigorous evidence was sparse and solutions elusive.
Has nobody tried to do intervention studies?
Yes, but the results were disappointing. For example, in the 1990s, the National Institutes of Health were sponsored two large, rigorous studies. The researchers wondered whether weight gain in children could be prevented by intervening in schools by expanding physical education, offering more nutritious canteen meals, teaching students about good 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 across the Southwest. Students there were mostly Native Americans, a group at high risk for obesity.
The schools were divided into two groups. Some schools received intensive intervention, while others were left alone. From the fifth grade onwards, researchers determined whether the children at the intervention schools weighed less than those at the other schools.
Unfortunately, they were not, although the students were very familiar with the importance of activity and proper nutrition. The children who received intensive treatment also ate less fat, from 34 percent to 27 percent of the total diet.
“It wasn’t enough to change body weight,” said Benjamin Caballero of the Johns Hopkins Bloomberg School of Public Health, the study’s lead researcher.