By SABRINA TAVERNISE
Despite years of efforts to reduce obesity in America, including a major push by Michelle Obama, federal health officials reported Thursday that the share of Americans who were obese had not declined in recent years, and had edged up slightly.
About 38 percent of American adults were obese in 2013 and 2014, up from 35 percent in 2011 and 2012. Researchers said the increase was small enough that it was not statistically significant. But to many in public health, it was surprising and disheartening.
“The trend is very unfortunate and very disappointing,” said Marion Nestle, a professor in the department of nutrition, food studies and public health at New York University. “Everybody was hoping that with the decline in sugar and soda consumption, that we’d start seeing a leveling off of adult obesity.”
And compared with a decade ago, the increase was significant: In 2003 and 2004, about 32 percent of adults were obese, said the report’s lead author, Cynthia L. Ogden.
Health experts had hoped that gradual improvements in the American diet in recent years might have moved the needle on obesity. Consumption of full-calorie soda has dropped by a quarter since the late 1990s, and there is evidence that calorie intake has dropped for adults and children. Obesity began rising in the 1980s, but the rate flattened in the 2000s, and declines among young children in some cities had lifted expectations that the epidemic might be easing.
Obesity among young people was unchanged in 2013 and 2014 from the previous period, the report found. Seventeen percent of Americans ages 2 to 19 were obese, the same as in 2003 and 2004. Experts pointed out that far more work had been done to fight obesity in children, including changes in school lunches and the removal of sugar-sweetened beverages from some school systems.
Noting that obesity did not rise for youth, Ms. Obama’s office said the focus of the first lady’s efforts has been childhood obesity. Federal figures from last year evenshowed a decline among the youngest children, said Debra Eschmeyer, executive director of Let’s Move, Ms. Obama’s anti-obesity campaign. “It is more than encouraging to see in today’s C.D.C. report that childhood obesity rates are no longer rising,” she said.
The figures are from the National Health and Nutrition Examination Survey, the gold standard for federal health data, released every two years. For smaller slices of the American population — for example, women or blacks — researchers used four years of data, from 2011 through 2014, for the most reliable results.
Some of the most striking numbers were among minorities. About 57 percent of black women were obese from 2011 to 2014, the highest rate of any demographic. Next highest were Hispanic women, at 46 percent, and Hispanic men, at 39 percent. About 36 percent of white women were obese, and 34 percent of white men. The prevalence of obesity was lowest among Asians, who had a combined rate of about 12 percent.
Dr. Walter Willett, the chairman of the nutrition department at the Harvard School of Public Health, cautioned that the modest improvements nationwide were extremely unevenly spread, with most of them happening among more educated Americans. A paper he helped write, published this month in Health Affairs, found that Americans’ diets had improved in quality from 1999 to 2012 — with a reduction in trans fats, small increases in fiber and less soda consumption — but that most of those advances were not happening among lower-income, less educated Americans.
“In general, there’s been a big gap” between rich and poor, Dr. Willett said. “When we take the U.S. average, we are hiding a lot of detail.”
There were a few other surprises. Men had more or less caught up to women in obesity prevalence in recent years, but the new numbers showed that women had edged ahead again, Dr. Ogden said. About 38 percent of adult women were obese from 2011 to 2014, the report found, compared with 34 percent of men.
Middle-aged Americans were hardest hit. Adults ages 40 to 59 had the highest rate of obesity, 40 percent, followed by people 60 and over, 37 percent of whom were obese. About 32 percent of 20- to 39-year-olds were obese.
Kelly D. Brownell, the dean of the Sanford School of Public Policy at Duke University, said the new figures were a reminder that many risks, such as the prevalence and inexpensiveness of junk food, had not gone away, and a sign that policy makers needed to redouble their efforts to, for example, impose a tax on soda.
“The emergency flag has gone up,” he said. “We are not doing nearly enough.”