What is childhood obesity?

What is childhood obesity?

Childhood obesity is a chronic disease characterised by such an increased amount of body fat that it entails health risks. In Sweden, it is diagnosed using iso-BMI — an age- and sex-adjusted BMI measure according to Cole 2000:

• Iso-BMI 30–34.9 = obesity (class 1)
• Iso-BMI 35–39.9 = obesity class 2 (severe)
• Iso-BMI 40+ = obesity class 3 (extreme)

The diagnosis is made by a doctor and is based not only on iso-BMI, but also on the trend on the growth chart, clinical assessment and investigation of any complications.

How common is childhood obesity in Sweden?

Approximately 6–7% of Swedish school-age children have obesity, and a further ~20% have overweight. The prevalence has increased in recent decades. See more detailed statistics in how many children in Sweden have obesity.

What is the difference compared to overweight?

Overweight is iso-BMI 25–30 and is not considered a disease — it can often be addressed with small changes to the family's daily routines. Obesity begins at iso-BMI 30 and is a chronic disease that should be treated within healthcare. See the difference between overweight and obesity in children for more detail.

How is childhood obesity treated?

Treatment is directed at the whole family, not just the child, and is based on several components:

1. Family-based behavioural treatment — structured support for mealtime routines, sleep, screen time and physical activity, often over 1–2 years.
2. Regular follow-up appointments — to monitor iso-BMI, well-being and any complications.
3. Medication — in severe obesity in adolescents, GLP-1 analogues (e.g. liraglutide, semaglutide) may be considered; see Ozempic for children.
4. Bariatric surgery — in very severe obesity in older teenagers, following careful assessment.

Treatment takes time — see how long does treatment for childhood obesity take.

Where do you turn?

• BVC (child health centre) or the school health service — for an initial assessment and referral onward.
• The primary care centre (vårdcentralen) — if the child is no longer covered by BVC or the school health service.
• BUMM (paediatric and adolescent medical clinic) or paediatric clinic — for investigation and treatment of obesity; see the pathway through an assessment at BUMM.
• Specialised obesity units — in cases of severe obesity or complications.

Many paediatric clinics in Sweden use digital treatment support from Evira in their obesity care. At evira.se, you can see which clinics are connected and how to contact them.

What complications are associated with childhood obesity?

Obesity in childhood increases the risk of:

• Type 2 diabetes and insulin resistance
• High blood pressure
• Fatty liver disease (NAFLD)
• Sleep apnoea
• Joint problems
• Mental ill-health, often secondary to stigmatisation

Early treatment reduces these risks significantly. Obesity in childhood often tracks into adulthood if left untreated.

Mind the language

Never tell a child that they are "fat", "need to lose weight" or need to "go on a diet". Research is clear: comments about weight and appearance from parents increase the risk of eating disorders and low self-esteem, without positive effects on weight. Treating childhood obesity is about the family's routines — not the individual child's body.

Related questions

• 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 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.
• 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.

See all questions and answers →