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Childhood obesity coverIn 1963, doctors and nurses from the National Centre for Health Statistics set out around the country in specially fitted out Winnebagoes. They were going to take a tape measure to American children’s health. That study—the National Health and Nutrition Examination Survey—is still going today. The survey shows that childhood obesity has steadily risen, more than tripling in the fifty years since those doctors in the 1960s first hit the road with rulers and scales. The increases were even bigger in African American and Hispanic children. But last week researchers from the Centre and from the Public Health Service reported a new development: for the first time since the study began, rates of obesity had dropped in 2- to 5-year-olds. In young children, obesity is still more common than it was back in the 1960s, but is about 40% lower than its peak in the early 2000s. In older children, the inexorable rise over the past fifty years seems to have plateaued and hovers at around 17%. This is cause for cautious—very cautious—optimism.

It has been true for a long time that American kids are big, and have been getting bigger. In 1877, a Boston physician named Henry Bowditch carried out the first significant study of American children’s heights and weights. He had teachers in Boston schools measure their pupils’ heights and weights. With no calculators or computers in the nineteenth century, Bowditch got Beantown’s accountants to crunch the numbers. Even then, American children were larger—taller and especially heavier—than children in Europe. At a time when undernourishment was the major childhood nutritional problem, the fact that American children were big was something to be proud of. Bowditch didn’t consider that there could be “too big”. Tall and heavy, American children were strapping specimens compared with their spindly European peers. The American way of life with its opportunities, its egalitarianism, its freedoms, was being written onto children’s bodies.

Over the next century, American kids kept getting bigger. By the time the National Health and Nutrition Examination Survey was launched, an eleven-year-old boy was about 4 inches taller and 16.5 pounds heavier than a boy of the same age in Bowditch’s time. This process is called “secular change” and is generally attributed to better nutrition and better health and housing allowing children to achieve their genetic potential for growth. The increase in children’s size up to about the 1960s was thought to be a sign of good things. But after about 1970, with children still getting bigger and especially getting heavier more than they were getting than taller, there was a growing sense that a tipping point had been passed. Children were becoming “too big” and bulk brought potential health problems.

The big increase in childhood obesity since the 1960s is also a sign of how the American way of life is still shaping children’s bodies, but in ways that we no longer think are desirable. The childhood obesity epidemic has been implicated with aspects of modern life—car driving, computers, television, working families, unsafe neighborhoods, and cheap, calorie-dense food pushed by massive marketing campaigns. Ironically, some of the major culprits fuelling obesity in adults and children are things that we enjoy and have worked hard to achieve. It’s not that children have changed in any essential way to cause the increases in obesity that the National Health and Nutrition Examination Survey has found, but the American way of life has become steadily more “obesogenic”.

Exactly why in recent years the rate of obesity should have dropped in young children is not entirely clear. But, because the drop has happened in young children, it seems likely that this change is due to families changing their habits. Good job Mom and Dad. This, of course, is much easier to do when children are young. It gets harder once children start school and go out into the world. Spending more time out of the house, kids have to deal with the environment they find there, and that environment seductively encourages obesity. The federal government’s program to address childhood obesity, Let’s Move, has put a lot of emphasis on arming children against this environment. First Lady Michelle Obama is routinely photographed doing yoga with grade-schoolers, or picking beans in the White House vegetable patch. She heads up the charge to get children to resist the lures of their environment and adopt healthy habits from the get go.

Let’s Move is heavy on “encouraging”, “educating” and “empowering” children to take responsibility for their eating and exercise habits. It’s a tough ask. Adults struggle to make good choices in their eating and exercise. All too often convenience, price, and advertising favor bad choices. Asking a kid to deal with all that is even harder. So it’s no surprise that the NCHS data show that obesity has not dropped in older children in the thick of this obesogenic mayhem. Programs like Let’s Move may have helped halt the rise of obesity in older children, but have yet to make inroads on current levels. Actions to tackle the obesogenic environment have been politically harder to implement, but there have been some notable efforts such as selling healthier beverages in school canteens.

With luck, the decline in obesity in 2- to 5-year-olds will stick. If this cohort maintains these lower levels of obesity as they get older, rates of childhood obesity will drop across the board. Let’s Move will have achieved its aim of “solving the challenge of childhood obesity within a generation”. But a generation is a while to wait, and is little use to children now in that 6-19 age bracket, for whom about 1 in 5 are obese. There is more that can be done to make healthy choices the convenient, cheap choices. Children shouldn’t have to be always on the defensive and they shouldn’t have to be tender experts on diet and exercise. These latest results may be the beginnings of change, but the childhood obesity epidemic isn’t history yet.

Interested? Want more? Check out my new book Childhood Obesity In America: Biography of an Epidemic, available from Harvard University Press and Amazon