When is overweight in children something to take seriously?

Young children are allowed to have body fat — it is protective

It is entirely normal for children under two years of age to have a high proportion of body fat. During the first years of life, fat is primarily protective — it serves as an energy reserve if the child becomes ill and loses their appetite. It is only from around two years of age that a high weight can begin to adversely affect health, which is why healthcare services begin using iso-BMI as an assessment tool from that age.

Between one and six years of age, it is normal for BMI to decrease slightly — this is the natural course of development. After around six years, the curve turns upwards again ahead of puberty.

Signs that overweight is becoming something to take seriously

Overweight is not always the same as obesity, and not all children with overweight develop ill health. However, there are patterns that should prompt a parent to contact healthcare services:

1. A break in the trend on the BMI curve. If the child's BMI curve suddenly rises more steeply than before — even if the value remains within the "normal" range — this is often the first sign of an unhealthy development.

2. Iso-BMI crosses 25 or 30. An iso-BMI of 25 corresponds to overweight, and an iso-BMI of 30 corresponds to obesity. Obesity is a chronic disease and should always be investigated by a doctor. Unsure where your child falls? Calculate iso-BMI here.

3. Weight increases whilst linear growth slows. If the child's height growth decelerates while weight continues to increase — and this cannot be explained by puberty having finished — it is a medical warning sign.

4. Symptoms related to overweight. Signs such as shortness of breath during light physical activity, joint pain, snoring or breathing pauses during sleep, high blood pressure, persistent thirst or increased urination may indicate that overweight has begun to affect health.

5. Psychosocial signs. Bullying, avoidance of physical activity, low self-esteem or social withdrawal related to weight are in themselves reasons to seek help — regardless of what the scales show.

6. Strong family history of obesity or related conditions. If there is obesity, type 2 diabetes or cardiovascular disease in the family, the child's weight development should be monitored particularly closely.

What happens during an investigation?

If the BVC (child health centre), school health service or health centre detects overweight or obesity on the BMI curve, they can carry out an initial assessment and, if necessary, refer to a BUMM (paediatric outpatient clinic). There, the following is conducted:

• Medical assessment. Blood tests to rule out type 2 diabetes and evaluate liver function, blood lipids and thyroid function. Blood pressure measurement. If necessary, a sleep assessment.
• Family history assessment. Questions about overweight, diabetes and cardiovascular disease in the family.
• Discussions about diet, physical activity, sleep, screen time and mental health.
• Assessment of pubertal development.

On the basis of this, a treatment plan is drawn up together with the family.

When should you seek help — and where?

Contact BVC if the child is under six years old and you are concerned about their weight development.

Contact the school nurse in the school health service if the child is of school age. The school nurse measures and weighs children regularly and can carry out an initial assessment.

Contact your vårdcentral (health centre) if you are not satisfied with the response from the school health service or if the child has clear symptoms.

Request a referral to BUMM if iso-BMI is in the obesity range (30+) or if there is comorbidity.

In cases of severe obesity or when treatment at BUMM level is not sufficient, a referral can be made to Rikscentrum Barnobesitas (the National Childhood Obesity Centre) at Astrid Lindgren Children's Hospital (for children up to 16 years of age).

What should you not do?

• Do not tell the child that they are too fat, look fat, or need to lose weight. Weight-focused comments from parents increase the risk of eating disorders and damage self-esteem — without having any positive effect on weight.
• Do not put the child on a diet. Children should not "diet". Treatment of childhood obesity is about the family's habits, not about restricting the child's calorie intake.
• Do not wait too long. Obesity is a chronic disease, and early treatment yields better outcomes. If iso-BMI reaches 30, it is not the time to wait until the next routine health check — it is time to seek healthcare.
• Do not compare with other children. Every child has their own growth curve and their own life circumstances.

Good news from research

Recent Swedish research from Sahlgrenska shows that children who reach a normal weight before adulthood have roughly the same risk of coronary heart disease as individuals who had a normal weight throughout their childhood. It is a reminder that interventions during childhood make a real difference — and that it is rarely "too late".

Related questions

• Why is my child gaining weight so fast?Common causes of rapid weight gain and when you as a parent should seek healthcare.
• 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.
• 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.

See all questions and answers →