Childhood obesity: a growing public health issue

Obesity is a growing problem around the world, a problem that comes with many health risks. It’s not just adults who are affected, though. Childhood obesity is ever-increasing, affecting nearly 20% of American children. The same health risks of obesity that impact adults apply to children with obesity, too. 

Let’s look at how common childhood obesity is, what’s caused it to become so common, health risks associated with childhood obesity, and what you can do to help.  

Roughly 18.5% of children ages 2–19, or about 13.7 million children and adolescents, have obesity, according to the Centers for Disease Control and Prevention (CDC), but some groups are more affected than others (CDC, 2019). 

“The number of children with overweight or obesity varies by age, ethnicity, and income status and is different in different countries,” according to Dr. Michael Goran, Ph.D., Professor of Pediatrics and Program Director for Diabetes and Obesity at The Saban Research Institute at the Children’s Hospital Los Angeles and USC Keck School of Medicine. Dr. Goran’s forthcoming book, Sugarproof, focuses on how parents can protect their children’s health. 

“For example,” Dr. Goran says, “in Los Angeles, in affluent neighborhoods, only 5% of kids [have obesity] versus 35% in low-income neighborhoods.” That means nationwide statistics are only telling part of the story.

There's also some confusion about where we stand regarding childhood obesity in the United States and whether new policies make a dent.

Research published in 2016 suggested that childhood obesity rates were stabilizing, but according to other researchers, that isn’t the case (Ogden, 2016). Childhood obesity rates are not decreasing, and further research shows that severe obesity is increasing in Hispanic children (Hales, 2018; Skinner, 2018).

Childhood obesity doesn’t have a set body mass index (BMI) as it does for adults “because BMI changes with age (and sex) as children grow,” says Dr. Goran. Instead, he explains that healthcare providers use percentile charts to compare children’s BMI to the expected BMI of same-sex peers in their age group. In children, a BMI >85th percentile is the clinical definition for overweight; >95th percentile is the clinical definition for obese (Barlow, 2007).

The causes of childhood obesity break down into two groups: nature (a.k.a. genetics) and nurture (environmental factors around a child that promote weight gain).

Children are more likely to have obesity if they have at least one parent with obesity. One nationwide study that looked at over 23,000 children and adolescents found an association between parental BMI and their children's weight (Bahreynian, 2017).

Does this parent-child connection fall under nature or nurture? Most likely, a bit of both. 

There are developmental factors that increase the likelihood that a child will have obesity. Dr. Goran points out that “exposure to smoking, sugar, sweeteners, or some other obesogenic chemicals in utero is associated with greater risk of childhood obesity.” 

Obesogenic chemicals are substances believed to interfere with your body's normal function—including things like appetite—and promote fat gain (Janesick, 2016). But the most persistent factor is the family lifestyle, like the amount and type of food consumed and activity level (Gray, 2018).

We see the effects of a vicious cycle, according to Dr. Goran.

“Overweight and obese mothers tend to give birth to babies who become overweight or obese,” he explains. “One issue we focus on in Sugarproof is that babies are born with an innate preference for sweetness. This was meant to be protective from an evolutionary perspective but has backfired in today’s high sugar food environment, where 70% of processed foods and 80% of kids snacks have added sugar.” 

Essentially, all kids are hardwired to prefer sugar. Still, parents ultimately control how those desires are met—whether that's with snacks with high levels of added sugar or with foods with natural sugar content such as fruit and milk.

But that doesn’t begin to capture the extent of this multi-factorial problem. Researchers have underscored that we cannot ignore changes to the global food supply and how it has become more processed but also more affordable and heavily marketed (Swinburn, 2011). Combine that increasing exposure to electronic media, and it may be a recipe for weight gain. 

TV consumption and video game playing aren’t simply sedentary activities that are being chosen over physical activities. Studies have found an association between playing video games and increased consumption of high-calorie foods and drinks (Calvert, 2014). Some information gathered from adolescents suggests that some may even be addicted to these highly pleasurable foods (Pretlow, 2011).

Childhood obesity is one of the risk factors in several chronic diseases and health problems—and these medical conditions can impact both a child’s longevity and overall happiness.

Type 2 diabetes

One study found that children with obesity are four times more likely to develop type 2 diabetes than children with normal weight (Abbasi, 2017).

Increases in childhood obesity in the United States have been mirrored by increases in children diagnosed with type 2 diabetes. One study found that, after controlling for race, age, and sex, the number of American youth with type 2 diabetes increased 4.8% annually between 2002 and 2012 (Mayer-Davis, 2017). Type 2 diabetes in childhood may put kids at a higher risk of other serious conditions such as kidney failure, vision impairment, and dangerous changes in heart health (Xue, 2016).

Asthma

It’s estimated that between 23–27% of asthma cases in children with obesity are directly caused by obesity (Lang, 2018). One review found that the combination is more difficult to control, comes with more symptoms, is more frequently and severely triggered, and responds less to inhaled corticosteroids. It’s also associated with a lower quality of life (Genova, 2018). 

Heart disease

One systematic review and meta-analysis of past research found that childhood obesity is significantly associated with multiple risk factors for the development of cardiovascular disease (CVD), also called heart disease, like high blood pressure. Those with higher body weight in childhood were more likely to develop high systolic blood pressure. High systolic blood pressure is more problematic than high diastolic blood pressure, according to the American Heart Association), high triglycerides, and low ("good") HDL cholesterol (Umer, 2017; AHA, n.d.).

Sleep apnea

Sixty percent of children with obesity suffer from obstructive sleep apnea, a condition in which the upper airways are blocked while sleeping because of excessive force, one review found. Sleep apnea in children causes everything from snoring to continual disruptions in sleep (Narang, 2012).

Joint pain

Young children with excess weight are also more likely to experience joint pain. In fact, one study found that the risk of experiencing musculoskeletal pain in the back, hips, knees, or ankles increased by 10% for every 10 kg increase of weight (roughly every 4.5 pounds) and 3% for every unit increase in BMI (Smith, 2014). 

Depression

One study found that children and adolescents with obesity have an increased risk of experiencing both anxiety and depression. Females with obesity in the study had a 43% higher risk of experiencing both of these mental health conditions than their normal-weight peers (Lindeberg, 2020). A meta-analysis of 18 studies that included 51,272 participants across multiple countries found similar results (Quek, 2017).

Poor self-image and self-esteem

One study found that children with obesity are more likely to show symptoms of poor self-image and self-esteem than their normal-weight peers. Adolescents who were female, pre-teen, had a higher BMI, and whose parents deemed them overweight were most likely to suffer from low self-esteem. Disturbed eating habits and bullying were also strongly associated with poor self-esteem for children with overweight (Danielson, 2012).

There are several strategies parents can take to help their children achieve and maintain a healthy weight. These strategies can decrease the risk of conditions associated with childhood obesity. While parents can implement many strategies at home, factors affecting a child's weight status go beyond the home. If you're able, there are also strategies for helping children develop healthy habits even when they're not home.

Encouraging physical activity as a family

Physical activity is an important part of preventing childhood obesity. While "we need major changes to the current food system and food environment," according to Dr. Goran, there is evidence that physical activity is a particularly important factor in kids and adolescents. In fact, while in adults, a combination of diet and exercise is more effective for weight loss than either intervention alone, exercise alone seems to be the most critical intervention for kids and adolescents (Clark, 2015; Brown, 2019). 

So, starting to exercise together as a family can be very effective.

Promoting healthier lunches in schools

Addressing food at home isn’t enough to counter adolescent obesity, though, when children eat up to 50 percent of their daily calories while in school. If you have the time, petitioning for healthier lunches at school would also help. 

Overall, Dr. Goran says the mission with your kids should be to "reset their eating style" to prefer healthy food and rely less on processed foods and fast food.

Research shows that more nutritious school lunches do have a positive impact on eating habits. More nutritional school lunch regulations, which may also help control portion sizes, resulted in students eating more fruit, throwing away fewer vegetables, and consuming the same amount of dairy, one study found (Schwartz, 2015). 

Decreasing screen time

Cutting down on time spent in front of video games or the TV may help, as long as it’s replaced with a healthier activity. As mentioned, studies have found that these screen-time activities aren’t just associated with a sedentary lifestyle, which may promote weight gain, but also with higher consumption of high-calorie foods and drinks. Replacing video game time with a family activity outdoors not only provides exercise but also eliminates an opportunity to snack while distracted.

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Current version

October 05, 2020

Written by

Linnea Zielinski

Fact checked by

Mike Bohl, MD, MPH, ALM

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About the medical reviewer

Mike Bohl, MD, MPH, ALM

Dr. Mike is a licensed physician and a former Director, Medical Content & Education at Ro.