The prevalence of obesity in the U.S. largely leveled off over the last decade, even as some individual groups, such as boys from ages 6 to 19, saw increases, according to government data.
Obesity rates in adults rose slightly to 35.7 percent from 30.5 percent between 1999 and 2010, compared with rates that nearly doubled in the two previous decades, the Centers for Disease Control and Prevention reported today. The rate among boys climbed 29 percent, surpassing girls for the first time, according to the Atlanta-based health agency.
“There is really a slowing down of the rapid increase in the prevalence of obesity that we saw in the 1980s and 1990s,” said Cynthia Ogden, a CDC epidemiologist and the report’s lead author, by telephone. “Those increases we saw earlier are not continuing, and we may be seeing a plateau.”
More than 78 million U.S. adults, or a third of the population, and about 12.5 million children were obese in 2009-2010, according to the studies reported in the Journal of the American Medical Association. The studies are part of a continuing CDC effort to track obesity rates with updated numbers every two years.
The researchers analyzed data from the National Health and Nutrition Examination Survey, which weighs and measures participants, producing the most accurate details available, Ogden said. The analysis found virtually no changes since 2007, she said.
Changing the Environment
Until recently, the focus toward solving obesity was on fad diets and possible designer drugs, according to Kelly Brownell, director of the Rudd Center for Food Policy & Obesity at Yale University in New Haven, Connecticut. Those won’t work on a national scale because obesity is difficult to reverse once established, he said.
Now that public health authorities have targeted obesity as a driver of illness and death, akin to smoking or traffic fatalities, they are increasingly finding ways to change the environment to encourage healthier eating and physical activity habits early in life, he said.
New York City was able to reduce the obesity rate among grade school children 5.5 percent from 2006 to 2010 by boosting physical activity and encouraging healthier eating habits.
The percentage of obese kids in kindergarten through eighth grade in New York City schools fell to 20.7 percent in the 2010-2011 school year, from 21.9 percent in 2006-2007, according to a study by the city’s health and education departments.
Obesity has been shown to boost the risk of heart disease, diabetes, some cancers, osteoarthritis, sleep apnea and stroke, the CDC has said. Americans spend about $147 billion a year on obesity-related health costs.
“It was all about how to remedy obesity once it occurred, the problem is it is a really hard problem to reverse, so you want to prevent it,” The Rudd Center’s Brownell said. That’s only starting to happen, with efforts to limit soda and junk food in schools and other programs, Brownell said.
“The general population knows that obesity is problem, but unfortunately attention doesn’t equal results,” said Nisa Maruthur, an assistant professor of medicine at Johns Hopkins School of Medicine in Baltimore, by telephone.
The continued creep of the scale among males and African American women show that targeted programs are needed to try to reduce obesity rates, she said. Unfortunately, there’s no way to pinpoint why those groups in particular are still battling with weight gain on a broad level, Maruther said.
Boys Rate Disconcerting
The most disconcerting finding is the increase in obesity rates among boys, which is now surpassing levels in girls, said Hu, who wasn’t involved in the research.
“The overall trend, even though it’s not as fast as before, is still going up gradually,” said Frank Hu, professor of nutrition and epidemiology at Harvard School of Public Health in Boston, in a telephone interview. “Despite all the effort and all the money we’ve put into obesity control, there is no sign the epidemic is abating. If anything, obesity rates are actually inching up, especially in some groups.”
The U.S. Health and Human Services department has awarded more than $119 million to states and territories for programs to reduce obesity since 2009, including increasing physical activity and improved nutrition.
More than a dozen states have also banned soda from school vending machines and lunch lines, and some restaurant chains, including McDonalds Corp., Chick-fil-A Inc. and Darden Restaurants Inc., have committed to cut calories in their foods.
‘Unacceptably High Level’
“The fact that prevalence rates are reaching a plateau is good news, but by no means are we at the end of the epidemic,” said David Ludwig, a pediatric endocrinologist and director of the New Balance Foundation Obesity Prevention Center at Children’s Hospital Boston. “Unless we see declining rates of obesity the impact on society will continue to mount for many years to come. The plateau is at an unacceptably high level.”
According to the reports, men became more obese in the latest decade, rising to 35.5 percent at the end of the decade from 27.5 percent. The rate among women didn’t significantly change over the time period, finishing at 35.8 percent.
Among all sexes and age groups, women 60 and older had the highest prevalence, with 42.3 percent.
Obesity rates for boys ages 2 to 19 rose to 18.6 percent in 2009-2010 from 14 percent in 1999-2000, while the rate for girls was little changed at 15 percent.
One reason why boys may be getting obese faster than girls is the ever-growing use of video games, the Internet, and electronic devices, said Jacob Warman, chief of endocrinology at the Brooklyn Hospital Center in New York.
“Even though the schools are emphasizing exercise at the gym, there are more things that take their attention away,” making kids sedentary, he said in a telephone interview. Girls are more self-conscious about their bodies than boys, which may counteract the trend toward more screen time, Warman said.
Marion Nestle, a professor of nutrition and food studies at New York University, said fast-food establishments also tend to target boys and young men.
“Marketers encourage boys and young men to eat and drink as much as they can as part of macho lifestyles,” Nestle wrote in an e-mail. “The bigger the portions, the more the calories, and the bigger the person.”
While public health officials have been pushing healthier lifestyles to combat the epidemic, drugmakers such as Arena Pharmaceuticals Inc., Orexigen Therapeutics Inc. and Vivus Inc. are competing to develop the first new obesity drug approved by regulators in more than a decade.
Their efforts have been stymied by side effects deemed too risky to win marketing approval by the U.S. Food and Drug Administration.
“You will see a drug approved in the next five years, but it won’t be a perfect drug,” said Steve Brozak, an analyst with WBB Securities in Clark, New Jersey, in an interview.
Vivus’s diet pill, Qnexa, has been shown to be associated with oral clefts in babies whose mothers took it in pregnancy. Orexigen halted development of its drug, Contrave, for three months last year after the FDA said a large study on heart risks would be required for approval. It now plans to start such a trial this year.
Arena’s lorcaserin was rejected by the FDA in 2010, after a rat study showed a possible link to brain tumors. Follow-up studies concluded concentrations of the medicine were less in human brains than rats, and the FDA has accepted a resubmission for approval.
Any diet pill that wins approval with negligible side effects would generate unprecedented sales, bigger than Pfizer Inc.’s $10.7 billion cholesterol pill Lipitor, Brozak said.
“This is a Carl Sagan number -- ‘billions and billions,’ as he used to describe all the stars that are out there,” Brozak said.
While no one in the public health world would deem the levels of overweight and obesity in the U.S. acceptable, it’s important to consider the environment facing the average American, said Maruther at Johns Hopkins. There might be a “sense of normalcy” among people whose peers are a similar size and have the same sedentary lifestyle, she said.
“One thing might be culture,” she said. “It might be that everyone around me is the same weight as I am, and our lifestyle and work habits are similar in general. That’s part of the challenge. It’s an uphill battle, for sure.”