Dispatches from the Battle of the Bulge

As if looking in the mirror weren't scary enough for the two of every three American adults losing the battle of the bulge, studies published recently by Bloomberg School researchers have uncovered more evidence that carrying extra pounds can harm health and drive up health care costs. The effects can be felt almost from the cradle to the grave, and will likely get worse: One study warns that 8 in 10 Americans will be overweight or obese by 2030, if trends of the last three decades continue.

Children who don't get enough sleep are much more prone to weight gain, according to a study published in February in the journal Obesity. By analyzing a number of epidemiological studies, Bloomberg School researchers found that each additional hour of sleep was associated with a 9 percent reduced risk of a child being overweight or obese. Conversely, children with the shortest night's sleep—ranging from fewer than 9 hours for a 5-year-old to fewer than seven hours for children over 10—were 92 percent more likely to become overweight or obese.

Scientists speculate that hormone levels that help regulate body weight may become unstable when children don't get enough sleep, leading young people to eat more calorie-rich food, burn calories less efficiently and carry a higher risk of insulin resistance, among other factors.

The study's authors hope that parents and policymakers will use the information to educate children about the need for adequate sleep, as well as proper diet, in fighting obesity. "It's easier to reach children because they are in schools. It's particularly important to reach them because once they become obese, studies show that they're very likely to end up as obese adults," says Youfa Wang, MD, PhD, associate professor of International Health and the study's senior author. Currently, about 16 percent of children and adolescents in the U.S. carry too much weight.

An ongoing analysis by Wang and others published in July in Obesity forecasts a fat future as Americans age. By 2048, the prevalence of overweight or obese adults might approach 100 percent if trends hold, Wang says, leading to additional health care costs of nearly $1 trillion annually by the year 2030, or approximately $1 in every $6 of total health care costs.

Government policies and programs that encourage people to eat less and exercise more would go a long way toward forestalling this public health crisis, says Wang, as would new guidelines on food marketing, portion sizes and school meal programs.