It looked as though the tide was turning in the battle against childhood obesity, based on a recent report from the Centers for Disease Control and Prevention (CDC). That study suggested a drop in the obesity rate for U.S. preschoolers. But now, a new study, published in JAMA Pediatrics, shows that severe obesity in children is actually on the rise.

The new study found that all classes of obesity in U.S. children have risen exponentially over the past 14 years. Children with severe obesity have a body mass index (BMI) that is 120 to 140 percent higher than their peers.

These findings are based on a new analysis of data from 1999 to 2012, collected from 26,690 children ages two to 19, as part of the National Health and Nutrition Examination Survey (NHANES). 

More than 17 Percent of U.S. Children Obese

Asheley Cockrell Skinner, Ph.D., lead author of the study and an adjunct assistant professor of pediatrics at the University of North Carolina (UNC) School of Global Public Health, told Healthline, “We were interested in the most severe forms of obesity, which are class 2 and 3, and this is what we think about with morbid obesity in adults. We see that over the last 14 years, there’s definitely been an increase in both of these levels of obesity. We see a significant increase in severe obesity at a variety of different ages.”

Pointing out that the earlier study was based on just two years of data, Skinner said, “We used exact same data and definitions, but since we went back to 1999 it gives us a longer view. You can really see there haven’t been any decreases [in obesity rates] at all.”

See How Schools Can Make Children Healthier »

According to the study, a ten year old boy who is OF average height (four and half feet tall) and weighs 95 pounds would be considered obese, but would meet the criteria for class 2 obesity at 115 pounds and class 3 obesity at about 130 pounds.

Using these definitions, the study found that 17.3 percent of U.S. children ages two to 19 were categorically obese in 2011-2012. At the same time, 5.9 percent met the criteria for class 2 obesity and 2.1 percent for class 3 obesity.

Commenting on the findings, Alissa Rumsey RD, CDN, CNSC, CSCS, a registered dietitian and spokesperson for the New York State Dietetic Association, told Healthline the most worrisome finding is “the increase in extremely obese children and teenagers (those with a BMI greater than 120-140 percent of their peers), from 3.8 percent up to 5.9 percent from 1999-2012.”

Skinner said that elementary school girls and adolescent boys had more severe obesity, particularly class 3.

The reason why these two groups saw an increase in severe obesity is unclear, but Skinner said, “It may be due to puberty timing. We know in girls if they are very obese they will often have puberty onset a little bit earlier.”

Learn More: New Genetic Test to Detect Childhood Obesity »

TV, Junk Food, Video Games Are Culprits

TV watching, eating junk food, and playing video games are partly to blame, but there are certain kids who are predisposed to being overweight, said Skinner.

“In this environment, their obesity gets much worse," she said. "We see a steady increase; we certainly don’t see any declines anywhere."

Are parents and schools partly at fault? “Parents know this is a bad thing and schools know but nothing seems to be working," she added. "It’s an entire culture that has made it more difficult to buy and eat healthy food. People are busier. They feel it’s not safe enough for kids to play outside.”

Skinner also told Healthline that one of the main concerns for children who are overweight is whether they have good diet and exercise habits that will follow them into adulthood. “For those with severe obesity, we worry about them already starting to have health problems, such as teenagers getting type 2 diabetes,” she said.

Watch: 10 Healthy Habits To Teach Your Kids »

Interventions Can Make a Difference

Skinner advised that parents ask about medical interventions that might help their children develop a healthier lifestyle. “Parents shouldn’t be afraid to ask for help. Parents need to be aware this is not a problem that’s going away. Most of those programs are complete lifestyle programs, with diet and exercise and usually for the whole family,” said Skinner.

How about weight loss camps? Skinner said, “Under no circumstances should a kid be sent to a 'fat camp.' The concern here is health, not whether or not the child is overweight or obese. If a physician feels a child is healthy and small changes can be made, not stigmatizing the child is the most important thing we can do. Because if you do you say, ‘You’re overweight and we will put you on a diet,’ those children are at really risk of not losing weight now and continuing to gain weight when they are older.”

While schools are trying to incorporate healthier foods into their menus, Skinner said, “That’s one meal a day. What happens for breakfast and other times of the day? More important, do kids have a chance to be active? For their entire life, every kid should be given opportunity to run and play outside and it doesn’t have to be structured activity or structured exercise.”

Rumsey agreed with Skinner about the need for a cultural change.

“Extra pounds can start a child on the path to serious health problems, such as diabetes, high cholesterol, and high blood pressure. With one in five children classified as overweight or obese, a culture and environmental change is needed. Children need to be getting daily physical activity and be given access to healthy foods. One of the best strategies is to get the entire family on board to improving diet and exercise habits,” Rumsey said.

Related News: Risk Factors for Childhood Obesity You Can Control »

Childhood Obesity Carries a Hefty Pricetag

In a separate study, published today in Pediatrics, researchers found that childhood obesity translates to about $19,000 more per child in lifetime medical costs, compared to a normal weight child.

Researchers at the Duke Global Health Institute and Duke-NUS Graduate Medical School in Singapore, found that when multiplied by the number of obese 10-year-olds in the United States, lifetime medical costs for this age group alone reached approximately $14 billion.

An alternative estimate, which takes into account the possibility of normal weight children gaining weight in adulthood, reduces the cost to $12,900 per obese child.

Lead author Eric Andrew Finkelstein, Ph.D., M.H.A. said in a press release, “Reducing childhood obesity is a public health priority that has substantial health and economic benefits. These estimates provide the financial consequences of inaction and the potential medical savings from obesity prevention efforts that successfully reduce or delay obesity onset."