The CDC says the changes in the prevalence of adult obesity were so slight between 2011 and 2014 (the most recent data available) that they were not statistically significant.
And another note of optimism: The CDC finds childhood obesity has leveled off. In many states, as we've reported, obesity rates are falling among preschool-aged kids.
Health advocates say that's a sign of progress.
"We are excited to see that our nationwide efforts to prevent childhood obesity have stopped the decades-long increase in childhood obesity rates," said Howell Wechsler, CEO of the Alliance for a Healthier Generation, in a statement.
But he adds, "it is imperative that we double down on our efforts to go beyond flattening the rates so that we actually start decreasing childhood obesity rates."
If you dig into the data a little deeper, it's clear that middle-aged Americans are not as successful at avoiding weight gain — especially middle-aged women.
The prevalence of obesity among women in their 40s and 50s has risen to 42 percent since 1999-2000. That's higher than the 38 percent the CDC found for middle-aged men. Across all adult age groups, about 38 percent of women are obese, while 34 percent of men were obese.
Study author and CDC epidemiologist Cynthia Ogden says these gender differences are a new development. "This hasn't been the case for some years," Ogden says.
And, the divide becomes even greater for some women of color. The obesity rate among African-American women is 57 percent and 46 percent among Hispanic women.
"The biggest problem is that the obesity rates among low-income Americans and minorities are not improving," says obesity expert Barry Popkin of the University of North Carolina.
The medical and economic toll of this problem remains huge as well. According to Health Affairs, the obesity epidemic carries a $117 billion medical pricetag.