On Tuesday, Michelle Obama announced a new marketing ban on junk food and sugary drinks in schools across the U.S., hoping to break the associations of learning and unhealthy eating. Accompanying this announcement, and widely touted as a victory for the "Let’s Move!" campaign Obama began four years ago, was a study showing childhood obesity rates had fallen 43 percent over the last 10 years.

But don’t put this news in the win column just yet. The Centers for Disease Control and Prevention show that, by 2012, childhood obesity had more than doubled in children and tripled in adolescents in the last 30 years. The new study upholds this bleak picture, finding that 17 percent of all children between 2 and 19 years old are obese — otherwise old news from a public health perspective, but when paired with more hopeful-sounding statistics, makes childhood obesity seem to be slowly melting away. The truth is, it’s not.

Even the researchers behind the study agree the problem isn’t even close to solved. “Overall, there have been no significant changes in obesity prevalence in youth or adults between 2003-2004 and 2011-2012,” they wrote. “Obesity prevalence remains high and thus it is important to continue surveillance.”

Despite the news coming straight from the horse’s mouth, the reported focus was narrow — concentrating only on the slim 2- to 5-year-old age group, from two years ago. And while that age group acts as a strong predictor for obesity later in life, the razor-thin band of children makes up a tiny fraction of the entire population. Broadly speaking, obesity rates in the U.S. have never been higher. Some 35 percent of adults are obese.

Diets are changing, and thanks to Michelle Obama’s new legal efforts, sweeping policies in schools are making unhealthy eating much harder. (Begrudged healthy eating is still healthy eating, after all.) But a problem inherent in measuring obesity is that it can take a lifetime to fully develop. Continuous surveillance is requisite.

“Once the obesity epidemic emerged in the 1980s, it took us a while to realize that something bad was happening,” Ruth Loos, a professor of preventive medicine at the Icahn School of Medicine at Mount Sinai hospital, told The New York Times. “We’ve been trying to educate parents and families about healthy lifestyles, and maybe it’s finally having an effect.”

That’s the key word: maybe. A mishmash of evidence over the last few decades paints a splotchy, incoherent picture of Americans’ overall health, especially that of its children. Anecdotal evidence, we have in abundance — a veteran gym teacher here, a physician there — but little comprehensive data to show where our waistlines are headed. For instance, one landmark study from the American Heart Association pokes a giant hole in the present study’s apparent progress. The AHA found over the course of five decades, with data involving more than 25 million kids in 28 countries, children are less fit than their parents’ generation was at their age — measured by their ability to run a mile.

"It makes sense. We have kids that are less active than before," Dr. Stephen Daniels, a University of Colorado pediatrician and spokesman for the AHA said in a news conference last November. "Kids aren't getting enough opportunities to build up that activity over the course of the day. Many schools, for economic reasons, don't have any physical education at all.”

So the political hoopla of getting kids to move may be clear and present, and the installation of healthy foods the new normal, but the numbers show little progress, if any. Putting in 60 minutes of physical activity each day is ideal, though perhaps unrealistically so given the softening of recess and physical education combined with the unregulated screen time of video games and television. Obama, for her part, at least agrees the fight isn’t likely to finish while she’s still in the White House.

"While childhood obesity rates are beginning to fall, we still have a long way to go before we solve this problem once and for all," she said in a press conference Tuesday. "We can't slow down and we can't turn back now."

Source: Ogden C, Carroll M, Kit B, Flegal K. Prevalence of Childhood and Adult Obesity in the United States, 2011-2012. JAMA. 2014.