Key messages

• Multi-component treatment approaches (addressing diet, physical activity, and/or other behaviours) may improve children's physical activity (measured objectively) when delivered in healthcare facilities, and they may slightly improve quality of life when delivered in community settings. However, overall, we found they had limited effects on other critical outcomes, including physical well-being, mental well-being, and body mass index (BMI) z-score (a score showing whether someone's weight is higher or lower than what’s typical for people of the same age and sex).

• Benefits and risks of these behaviour-changing approaches for children and their parents remain uncertain, and most evidence in this review comes from high-income countries.

• More studies are needed in different populations and locations to understand what works and what doesn’t for different children.

What is the problem?

Childhood obesity is a global health challenge with many causes, including diet, physical activity, and behaviour. Obesity is usually defined as having a body mass index (BMI – a number calculated from a person’s height and weight to check whether their weight is in a healthy range) that is much higher than what is typical for young people of the same age and sex. Treatment approaches that encourage healthier lifestyle habits are often used to manage obesity in children, but their long-term impact remains unclear.

What did we want to find out?

We wanted to determine if multi-component health behaviour-changing treatments promoting better diet, physical activity, and behaviour help children living with obesity (under 10 years) and help their parents. We focused on how these interventions affect physical and mental well-being, physical activity, quality of life, and weight-related measures over the long term (at 12 to 24 months). We also considered their unwanted effects.

What did we do?

We searched for studies that tested health behaviour-changing treatments combining two or more areas: diet, physical activity, or behaviour change. We included only studies comparing these interventions to no treatment, usual care, or a waiting-list group, and with follow-up of at least one year from the start of the programme. We compared and summarised the results of the studies and rated our confidence in the evidence, based on factors such as study methods and sizes.

What did we find?

We found 34 studies involving 6849 children in high-income countries (North America, Europe, New Zealand, Australia, Israel). We divided the studies into two groups: (1) healthcare-based studies, which delivered treatments in healthcare facilities such as primary care treatment centres or hospitals; (2) community-based studies, which delivered treatments in schools, community centres, sports centres, or other public spaces.

Main results

Compared to usual care, healthcare-based multi-component behaviour-changing approaches:

• likely make little to no difference to children's physical well-being when measured as a final value;

• if measured as a change-from-base value (a score showing how much a person’s physical activity increased or decreased after the treatment programme compared with how active they were at the start), these interventions may improve physical well-being at 12 months, but we are very uncertain about the result;

• likely make little to no difference to children's mental well-being or health-related quality of life;

• may improve objectively measured physical activity, but result in little to no difference in subjectively measured physical activity;

• may make little to no difference to BMI z-score.

We are very uncertain if these treatment approaches led to any harmful or unwanted events. None of the studies reported on obesity-associated disability.

Compared to usual care, community-based multi-component behaviour-changing approaches:

• may make little to no difference to children's physical well-being, mental well-being, objectively measured physical activity, and quality of life at 12 months;

• likely make little to no difference to mental well-being and objectively measured physical activity at 24 months;

• may slightly improve quality of life;

• likely make little to no difference to BMI z-score.

None of the studies reported on obesity-associated disability or the occurrence of any harmful or unwanted events.

What are the limitations of the evidence?

We have little confidence in the evidence because the studies had limited long-term follow-up and limitations in their methods. Most were conducted in high-income countries, so we cannot be certain how well these interventions might work elsewhere and in different populations. Although the effects were small, they might be meaningful for subgroups of high-risk children.

How current is this evidence?

The evidence is current to February 2024.