Kids used to come back to school after summer vacation fitter and slimmer, but that’s increasingly not the case, according to childhood obesity experts in the Charleston area.

Over the last three decades, pediatrician Dr. Janice Key has witnessed the phenomena of summer weight gain in youth and has even toyed with submitting a grant to the National Institutes of Health to study fitness levels in August and May of each school year.

Key adds that while children tend to grow more in summer than winter, possibly due to Vitamin D exposure from the sun, they used to return to school “taller and thinner.”

That’s not always the case anymore, she says, especially for those children who live in unsafe neighborhoods and who experience “food insecurity,” meaning they lack of reliable access to a sufficient quantity of affordable, nutritious food. The preference to stay indoors and play video games during the increasingly hot summer also plays a role.

Now, thanks to programs such as the one Key helped spearhead — the award-winning MUSC Boeing Center for Children’s Wellness checklist and Doc’s Adopt programs — schools are the source for healthier food and more physical activities.

Key is not alone in noticing the perils of summer inactivity.

After school started, Louie’s Kids founder Louis Yuhasz started getting emails from school faculty members and parents noting the problem and seeking help from the nonprofit that focuses on combatting family obesity.

“Obviously, we hear from a lot of families at the start of the new year because everyone is thinking about weight-loss, but the other time, sadly, is the start of the school year because kids are getting new clothes and new uniforms and their parents realize they have to buy bigger sizes,” says Yuhasz. “Sadly today kids spend most of their summer stuck inside playing video games and living pretty sedentary lives.”

The trend underscores the importance of what the MUSC Boeing Center and Louie’s Kids are doing as schools get down to serious business after Labor Day.

Key says concerned parents and faculty should seek to participate in school wellness committees and programs at many of the local schools.

The MUSC Boeing Center works with more than 260 schools in 11 districts in South Carolina, providing a template for creating a wellness culture on campus. In the coming two months, center staffers will be panning out across the state for checklist presentations and conducting school wellness leader trainings.

More immediately, Louie’s Kids cranks up its newest Family Race Program, starting Sept. 7. The cost for the twice-weekly program, which includes trainer-led workouts, is $45 for a family of four and $10 for every extra family member.

Similar to programs that prepare families to participate in the Cooper River Bridge Run and Walk and Floppin’ Flounder 5K, the fall Family Race Program is geared to preparing for the James Island Connector Run 10K or 5K.

Since childhood obesity rates have generally leveled off in recent years, thanks in part to first lady Michelle Obama’s focus on the issue, it seems to be receiving less attention in the media. But the problems of children being obese and overweight continue.

The Center for Disease Control and Prevention’s 2015 Youth Risk Behavior Surveillance System, published earlier this summer, show that a significant portion of older youth still suffer from being obese or overweight.

Figures for last year show that 13.9 percent of high school students were obese and another 16 percent were overweight.

State obesity rates among high school students ranged from a low of 10.3 percent in Montana to a high of 18.9 percent in Mississippi. Meanwhile, South Carolina’s rate was the eighth highest at 16.3 percent.

Increasingly, health officials are offering a simple template for parents to follow called the “5-2-1-0 Rule”: Eat five or more servings of fruits and vegetables a day; limit screen time to two hours or less, do one or more hours of physical activity, and have zero sugary drinks.

Last week, the American Academy of Pediatrics underscored the importance of another strategy for parents and physicians to take when dealing with overweight children. The academy says healthy lifestyle should eclipse the bathroom scale.

In new guidelines that address both teen obesity and eating disorders, the AAP says adults should move away from “weight talk,” and instead help kids have a healthy relationship with food and their bodies.

“We need to focus on health and healthy behaviors, rather than the number on the scale,” says Stanford pediatrics professor Dr. Neville Golden, the lead author of the new recommendations, in a statement.

The academy has long had guidelines on both childhood obesity and eating disorders, but the new report addresses both together because they are connected, says Golden.

Most teenagers diagnosed with eating disorders such as anorexia and bulimia were not overweight to begin with, according to Golden. But, he said, some overweight teens do develop eating disorders when they try to lose weight.

In an effort to shed pounds, Golden said, some kids turn to risky tactics such as fasting, using diet pills and laxatives, or excessive exercise.

To help ward off those problems, the academy says parents and doctors should steer teenagers away from the idea of “dieting.”

Marjorie Nolan Cohn, a New York City-based registered dietitian and spokeswoman for the Academy of Nutrition and Dietetics, agreed with the academy’s new guidelines.

Cohn says ensuring a kitchen is stocked with healthy foods, having family meals whenever possible and encouraging kids to have a positive body image offers better outcomes than diets.

Reach David Quick at 937-5516.