Growing up Heavy: What We Know About Childhood Obesity and What’s New on the Horizon

Imagine a child who, despite eating what seems like a reasonable diet and playing outside, still gains weight year after year. For millions of families, this is not hypothetical; it is everyday life. Childhood obesity is one of the most talked-about yet least understood health challenges of our time. This article explains what it is, why it matters, and what the latest scientific advances, including a new generation of medications, may mean for children and teenagers who are struggling.

What Is Childhood Obesity?

Doctors define obesity in children differently from how they define it in adults. Rather than using a fixed weight threshold, healthcare providers use something called the Body Mass Index (BMI), adjusted for a child's age and sex. A child is considered obese when their BMI falls at or above the 95th percentile, meaning they weigh more than 95 out of every 100 children of the same age and sex. Severe obesity is defined as reaching the 120th percentile of the age-adjusted BMI chart.

The distinction matters because children are still growing. What is a healthy weight at age 8 looks very different at age 15, and doctors account for this when assessing a child's health.
 

How Big Is the Problem?

The numbers are striking. In the United States alone, roughly 1 in 5 children between the ages of 2 and 19 are living with obesity.  That is approximately 14.7 million young people. Rates climb with age: around 13% of children aged 2–5 are affected, rising to 21% among 6–11 year olds, and reaching 22% among teenagers aged 12–19.

Globally, the picture is just as concerning. A landmark 2025 UNICEF report found that obesity has now overtaken underweight as the most common form of malnutrition among school-aged children worldwide — affecting 1 in 10, or roughly 188 million young people. For the first time in recorded history, more children globally are overweight than underweight.

These rates have roughly tripled since the 1970s in many high-income countries, and the trend is accelerating in lower-income nations too. Childhood obesity was once considered a problem of wealthy societies; today, it is a global crisis.
 

Key Numbers at a Glance

• ~1 in 5 US children (ages 2–19) live with obesity

• 188 million school-aged children worldwide affected (2025)

• Obesity rates in children tripled since the 1970s

• About 80% of adolescents with obesity will remain obese into adulthood

Why Does It Happen?

Obesity is not simply a matter of eating too much or moving too little. It is a complex medical condition shaped by a combination of biological, social, and environmental forces.

Biological Factors
Genetics plays a significant role. Children with one obese parent have roughly a 50% chance of developing obesity themselves; if both parents are obese, that risk rises to around 80%. Beyond genetics, hormones that regulate hunger and fullness — including insulin, leptin, and ghrelin — can function differently in people with obesity, making it harder to feel satisfied after eating.

The Environment We Live In
Modern life makes it easy to overeat and hard to stay active. Ultra-processed foods are cheap, widely available, and engineered to be irresistible. Screen time has replaced outdoor play. Many families live in neighborhoods without safe parks or affordable fresh food. Social deprivation and food insecurity are strongly associated with higher obesity rates — a painful irony, given that obesity is often wrongly seen as a condition of excess.

Other Contributing Factors
Inadequate sleep disrupts hormones that control appetite. Certain medications (such as some used for epilepsy, asthma, or mental health conditions) can cause weight gain as a side effect. Stress — including the chronic stress associated with poverty, racism, or family instability — can also contribute to weight gain in children through both hormonal and behavioral pathways.

Why Does It Matter?

Childhood obesity is not just a concern for how a child looks or feels in the moment. It carries serious health risks — some that emerge in childhood, others that cast a long shadow into adult life.
Children with obesity are at higher risk of:

• Type 2 diabetes — once almost unheard of in young people, now increasingly diagnosed in teenagers

• High blood pressure and increased cholesterol, setting the stage for early heart disease

• Sleep apnea – disrupted breathing during sleep which affects concentration and mood

• Joint pain and mobility problems from excess weight on developing bones

• Non-alcoholic fatty liver disease, now called MASLD (Metabolic dysfunction-associated Steatotic Liver Disease)

• Anxiety, depression, and low self-esteem, partly driven by bullying and social stigma

The consequences do not disappear when a child grows up. Roughly 80% of adolescents with obesity will carry it into adulthood, raising their lifetime risk of heart disease, stroke, certain cancers, and early death. Addressing childhood obesity is therefore not just about the present — it is one of the most important investments a society can make in long-term public health.

Traditional Treatments: What Has Worked (and What Hasn't)

For decades, the main approach to childhood obesity was advice: eat less, move more, change your habits. Lifestyle interventions — combining dietary guidance, increased physical activity, and behavioral support — remain the foundation of treatment and can make a meaningful difference, especially when the whole family is involved.

However, for many children, lifestyle changes alone are not enough. Obesity is a chronic medical condition with strong biological drivers, and willpower cannot fully override them. This is why the medical community has increasingly turned to other tools, including medication and, in severe cases, surgery.

A New Chapter: GLP-1 Medications in Children and Adolescents

One of the most significant developments in obesity medicine in recent years has been the emergence of a class of drugs called GLP-1 receptor agonists (GLP-1 RAs). You may have heard of semaglutide (brand names: Wegovy or Ozempic) or tirzepatide (brand names: Zepbound or Mounjaro). These are GLP-1 RAs that have made headlines for their remarkable weight-loss effects in adults. What is newer, and what the research community is now actively studying, is how these medicines work in children and adolescents.

How Do GLP-1 Medications Work?

GLP-1 stands for glucagon-like peptide-1, a hormone your gut naturally releases when you eat. It helps regulate blood sugar and signals fullness in the brain, while slowing how quickly food leaves the stomach. This helps people eat less without feeling deprived. GLP-1 receptor agonists are medications that mimic this natural signal in a stronger, longer-lasting form.  Rather than forcing weight loss, they work by amplifying the body's own sense of satisfaction with less food. 

What the Research Shows: Key Clinical Trials in Young People

Semaglutide in Adolescents (Ages 12–18) — NEJM 2022

The landmark STEP TEENS trial published in the New England Journal of Medicine enrolled 201 adolescents aged 12–17 with obesity. Those taking once-weekly semaglutide injections alongside lifestyle support achieved an average BMI reduction of 16.1%, compared with just 0.6% in the placebo group. More than two-thirds of participants lost at least 10% of their body weight. In network meta-analyses comparing all GLP-1 drugs studied in young people, semaglutide consistently outperforms the others for both weight loss and BMI reduction.

Liraglutide in Children (Ages 6–12) — NEJM 2024

In September 2024, the New England Journal of Medicine published the SCALE Kids trial, the first large, randomized trial of a GLP-1 drug in children younger than 12. Over 56 weeks, children aged 6–11 who received liraglutide daily (combined with lifestyle advice) saw significantly greater BMI reductions than those on placebo. This trial opened the door to future treatments for younger children, though no drug is yet approved for this age group.

Meta-Analysis Across Age 6–19 — Pediatric Research 2025

A comprehensive 2025 meta-analysis pooling 11 randomized trials and over 1,000 children and teenagers aged 6–19 found that GLP-1 drugs produced, on average, a 4.3 kg reduction in body weight, a meaningful drop in BMI z-score, and a 3.8 cm reduction in waist circumference — all compared with placebo. The benefits extended beyond weight: blood pressure improved modestly, and cardiometabolic risk markers moved in a healthier direction.

Who Is Currently Approved to Receive These Medicines?

As of 2025, the regulatory picture is as follows:

• Semaglutide (Wegovy) — approved by both the FDA and the European Medicines Agency (EMA) for adolescents aged 12 and older with obesity (BMI at or above the 95th percentile)
• Liraglutide (Saxenda) — also approved by both the FDA and the EMA for adolescents aged 12 and older with obesity
• Children under 12 — no GLP-1 drug is currently approved for this group, though research (like SCALE Kids) is ongoing

The 2023 American Academy of Pediatrics Clinical Practice Guidelines now formally recommend considering GLP-1 medications for eligible adolescents as part of a comprehensive care plan, positioning them between lifestyle therapy and bariatric surgery in the treatment pathway.

Are They Safe for Young People?

Safety is, rightly, the first question parents ask. Based on the evidence so far, the news is largely reassuring but with important caveats.

The most common side effects of GLP-1s are gastrointestinal: nausea, vomiting, and stomach discomfort, particularly in the first few weeks. These are usually manageable by starting at a low dose and increasing gradually. Studies to date have found no significant increased risk of depression, suicidal ideation, or serious cardiovascular events in the pediatric populations studied, an important finding given concerns raised in adults.

However, long-term safety data in children is still limited. Researchers are actively monitoring for rare but serious events such as pancreatitis and gallbladder disease. Questions remain about potential effects on bone density, muscle mass, and pubertal development, all of which are critical during childhood and adolescence. These are not reasons to avoid treatment when it is medically warranted, but they are reasons why these medicines should be used only under medical supervision with regular monitoring.

There is also a practical concern: access and equity. Uptake of GLP-1 drugs among eligible adolescents remains very low, under 1% in US studies, with significant gaps along racial, socioeconomic, and gender lines. Boys, non-white adolescents, and those from lower-income backgrounds are less likely to receive a prescription, despite being disproportionately affected by obesity. Cost and insurance coverage remain major barriers, particularly in the United States.

What Does This Mean for Families?

GLP-1 medications are not a magic fix, and they are not for every child with obesity. They are powerful tools that work best when combined with dietary guidance, physical activity, and psychological support. They require regular injections (weekly or daily, depending on the drug), ongoing medical supervision, and a commitment to lifestyle changes alongside medication.

Childhood obesity is a complex, chronic condition, and the tools to address it are still evolving. GLP-1 medications have opened a promising new chapter, but much remains to be learned, especially in younger children, where the evidence base is still being built. That work is happening now. Ongoing clinical trials are studying weight-loss medications in children and adolescents aged 8 to 18. If you are interested in these studies for your child, call your nearest research center to see if they are participating. Trials like these are how the medical community learns who truly benefits, how to use these therapies safely, and where their limits lie. For families facing childhood obesity today, the most important step remains a conversation with a trusted pediatrician, one who can see the whole picture and, where appropriate, point toward the research and support that may help.
 

Suman Mayer, MD

Dr. Suman Mayer is a board-certified pediatric emergency medicine specialist with advanced training in pediatric critical care.

References

NEJM 2022 (STEP TEENS semaglutide trial); NEJM 2024 (SCALE Kids liraglutide trial); Pediatric Research meta-analysis June 2025; UNICEF Child Nutrition Report 2025; AAP Clinical Practice Guidelines 2023; JAMA Pediatrics April 2025.