According to the Centers for Disease Control and Prevention, 20% of the nation’s youth are obese.

That is, they have a “body mass index at or above the 95th percentile for children and teens of the same age and sex.”

Among 12-19-year-olds, the rate tops 22%.

One of every five children age 2-19 is obese.

There’s no doubt that obesity is a serious problem among children and adolescents. Some local experts addressed why we are seeing so many cases of obesity in American youngsters and what we can do to get those numbers to drop.

Heredity, diet and physical activity are cited as the three biggest factors in determining whether someone is “obese” or not. While we can’t control our genetics, how we fare in the other two categories plays a huge role in the growing trend of childhood obesity.

“Some children have a genetic predisposition to weight gain,” said Dr. Avni Vora, endocrinologist at Northwestern Medicine Palos Hospital. “This in combo with reduced activity, increased portions and more low-fiber foods create an environment for weight gain.

“Genetics are an important factor in a child’s propensity to gain weight,” Vora said. “We are still trying to understand all the factors that go into this. But this doesn’t mean that lifestyle cannot be effective in weight management and good health.”

The American diet has changed dramatically in recent decades while lifestyles have trended to be more sedentary, a combination that works against good health.

“Reduced activity as children spend more time inside on screens and an increase in processed food consumption, especially in the form of carbohydrates,” Vora said. “More families are on the go and often grabbing food wherever they can. Overall portion sizes have increased over time, as well.”

Lela Iliopoulos, advanced dietitian and manager of clinical nutrition at Northwestern Medicine Palos Hospital, reinforced the importance of food selection and physical activity.

“Obesity is a growing issue due to the ultraprocessed foods we are inundated with, the increasingly sedentary lifestyles we lead and the lack of attention to the quality and quantity of foods we are consuming,” she said. “The nutrition noise out there does not make it easy to discern good nutrition from fake fads (or nonevidence-based nutrition).”

Dr. Chantal Walker, board certified pediatrician at Coolspring Health Center in Michigan City and a Franciscan Physician Network doctor, noted that rates of childhood obesity have tripled since the 1970s.

Direct consequences of obesity include such physical conditions as diabetes and high blood pressure, and it can hurt mental health.

“It is generally understood that obesity in children puts them at risk for diabetes, high blood pressure, high cholesterol and heart disease,” said Walker. “It is not as well discussed that obesity in children can put them at risk for sleep apnea, bullying and low self-esteem. Sleep apnea can affect school performance. Poor school performance, low self-esteem and bullying can lead to anxiety and depressive disorders. Rates of depression and suicide among children and adolescents are also increasing.”

It also increases the likelihood of obesity through adulthood. “This puts children at risk of eye and kidney disease, heart and lung disease and stroke as adults,” said Vora.

Where you live and access to nutritious food and health care play a big role in the childhood obesity. “The American Academy of Pediatrics states that overweight and obesity are more prevalent among kids living in poverty, low-resource communities and immigrant families,” said Walker. “Rates are highest among Latino and Black youth compared to White and Asian youth.”

Causes are more complex than modeling a healthy lifestyle, staying active and making good food choices when access to and cost of healthy food are a barrier. “Socio-economics play a role for children who live in areas that are food deserts,” Vora said of areas that lack grocery stores and access to fresh food.

Exercise also remains key to combatting childhood obesity.

“Limiting screen time keeps the children from becoming sedentary. Daily physical activity and exercise are necessary to prevent obesity,” said Walker, who recommends addressing screen time at well-child visits. “Children who are active with sports or daily exercise are more likely to continue being active as teens and adults. It is not necessary to join a gym. Thirty minutes of robust activity that increases your heart rate is acceptable. Walking, running, swimming, dancing, etc.”

And she suggests using some of that allotted screen time for interactive video games that will get kids out of a chair and moving.

“Children enjoy games, so turning activities into a competition or obstacle course can be helpful,” said Vora. “Sometimes children need to try a few different types of activities before they find something they like.”

Exercise has added benefits of boosting mood and improving heart health. “Doing activities as a family or in a group, when possible, may motivate children to stay active,” said Vora, suggesting that “Participating in youth sports or just going for a walk around the neighborhood can be beneficial.”

When it comes to eating, it’s all about establishing good habits and the sooner the better. “Infants and toddlers with better eating habits become children with better eating habits,” said Walker.

Establishing set mealtimes, offering healthy options and discussing nutrition can build a good foundation that will serve children well throughout their lives. Implementing little changes such as eliminating juices and pop, which have a high sugar content, can make a big difference. Taking stock of what you’re eating and where you can improve is a good start and pediatricians can offer referrals to a dietitian or nutritionist.

Perhaps the most critical thing that parents can do in preventing childhood obesity is modeling a healthy lifestyle. “Children are more likely to make better food choices, limit screen time and exercise if the entire family is following a similar regimen,” said Walker. “Parents who model good eating habits can be extremely instrumental in preventing obesity.”

“The habits we form as children influence who we become as young adults and beyond,” Iliopoulos added. “Teaching children how to eat well from a young age will impact them in a positive manner their entire lives. Nutrition is the one way we can possibly alter the course of our genetic predisposition, maybe even prevent a condition.”