What is obesity in children?

Parents' most common questions

• BVC says my child's weight chart is deviating — what does that mean?What BVC means by a "deviating weight chart" — and when it is actually time to act.
• Can my child get fatty liver disease from overweight?Fatty liver disease is one of the most common complications of childhood obesity — but it is rarely visible without a blood test.
• Elevhälsan has called us in about my child's weight — what now?The school nurse has called you in — now what? Here is what the consultation looks like and how to talk to your child about it.
• How long does treatment for childhood obesity take?Treatment for childhood obesity is a multi-year effort — here is what the timeline looks like, from the first BUMM visit to the maintenance phase.
• How many children in Sweden have obesity?Approximately 7% of primary school children have obesity and 16% have overweight — here are the statistics in Sweden.
• How much should a child weigh?There is no single correct weight figure — how children's weight is assessed in Swedish healthcare.
• How much should an 11-year-old weigh?There is no single correct weight for an 11-year-old — how iso-BMI works at 11 years of age.
• How should I talk to my child about overweight?Research is clear — do not talk about the child's weight. How to talk about health instead.
• Is obesity hereditary?The heritability of BMI is 40–70%. But genes do not decide alone — here is how the family can influence the risk.
• Ozempic and Wegovy for children — what applies?What are the rules for Wegovy, Saxenda, and Ozempic for children in Swedish healthcare? Clinical overview.
• What causes obesity?Obesity is caused by an interplay between genetics, hormones, environment and habits — not willpower.
• What counts as overweight in children?Overweight in children corresponds to an iso-BMI of 25–30 — how it is assessed and when small changes are enough.
• What does a BMI of 14 mean?A BMI of 14 is critically low in adults — requires immediate medical attention.
• What does BMI 15 mean?BMI 15 is severe underweight in adults — for children, the interpretation depends on age.
• What happens during a BUMM assessment for childhood obesity?Step by step through the first BUMM visit — what is measured, which tests are taken, and how to prepare your child.
• What is a normal weight for a 10-year-old child?There is no single 'normal' weight figure — here is how iso-BMI works for a 10-year-old.
• What is a normal weight for a 12-year-old?Puberty, height and sex all play a part — this is how a 12-year-old's weight is assessed.
• What is childhood obesity?Childhood obesity is an iso-BMI of 30 or higher — a chronic disease that should be treated within healthcare.
• What is childhood obesity?Childhood obesity is an iso-BMI of 30 or higher — a chronic disease that should be treated within healthcare.
• What is class 3 obesity?Class 3 obesity is BMI 40+ — severe obesity with a high risk of comorbidities.
• What is overweight for a 10-year-old?BMI thresholds for a 10-year-old explained — why iso-BMI is not the same as the adult scale.
• What is the difference between overweight and obesity in children?Overweight and obesity are not the same thing — here are the cut-offs, and why the difference matters.
• What should I do if my child is overweight?Is your child overweight? How it is assessed and which practical steps help most families.
• When is overweight in children something to take seriously?The patterns that signal overweight needs investigation — and where to seek help.
• Why is my child gaining weight so fast?Common causes of rapid weight gain and when you as a parent should seek healthcare.

The difference between overweight and obesity in children

Overweight and obesity are two distinct conditions. Overweight means that a child weighs more than is healthy for their height and age. Obesity is a more severe condition where the amount of body fat is high enough to affect health — both physically and mentally. Obesity is classified by the World Health Organization and Swedish healthcare as a chronic disease, not a lifestyle choice.

The threshold between overweight and obesity in children is defined using international cut-offs (IOTF) that account for the child's age and sex. These correspond to adult BMI 25 (overweight) and BMI 30 (obesity), but on an age-adjusted scale known as iso-BMI.

How common is childhood obesity in Sweden?

Approximately one in four primary school children has overweight or obesity. In the 6–9 age group, around 23 per cent had overweight or obesity during the 2021/2022 academic year, of whom 7.2 per cent had obesity and 15.6 per cent had overweight. Prevalence increases with age, and there are marked regional differences across the country.

Among younger children (4-year-olds), prevalence is around 11 per cent, and among 11–15-year-olds, the proportion with overweight or obesity has increased from 7 to 15 per cent since the late 1980s.

Why is childhood obesity serious?

Obesity in childhood increases the risk of type 2 diabetes, high blood pressure, liver complications, sleep problems and mental health issues already during the childhood years. Without treatment, the condition typically persists into adulthood, leading to an increased risk of cardiovascular disease. At the same time, recent research from Sahlgrenska shows that children who reach a normal weight before adulthood do not have an elevated risk of coronary heart disease later in life — making early intervention particularly vital.

There is also a significant psychosocial dimension: children with obesity more frequently experience bullying, low self-esteem and depression. A respectful, non-judgemental approach is therefore central to all treatment.

How is childhood obesity diagnosed?

The diagnosis is made by a doctor or nurse at a BVC (child health centre), the school health service or a BUMM (child and adolescent medical clinic). They use the child's BMI growth chart, which shows how BMI has tracked over time relative to age-adjusted thresholds. A single measurement rarely tells the full story — it is the trajectory of the curve that matters most.

When obesity is suspected, a broader assessment is carried out. This may include blood tests (for type 2 diabetes, liver function and blood lipids), blood pressure measurement, and questions regarding family history, dietary habits and physical activity.

What helps?

The foundation of all treatment for childhood obesity is combined lifestyle intervention involving the entire family. The child should not go on a "diet" — the focus is on establishing sustainable routines around nutrition, physical activity, sleep and screen time together with parents and siblings.

In more severe cases of obesity, additional support may be required. Since 2023, national clinical guidelines have been in place in Sweden for the treatment of obesity in children and adolescents. Two medications in the GLP-1 receptor agonist class are approved for weight management from the ages of 6 and 12 respectively, and bariatric surgery may in specific cases be offered from the age of 15.