INTRODUCTION
Childhood overweight (including obesity) is prevalent in many
countries1 and associated with poorer physical and psychosocial
health across the life course.2,3 Furthermore, overweight is not
distributed evenly across the population and varies by ethnicity,
socioeconomic circumstances, gender and age.4,5 The high
prevalence and associated burden of childhood overweight
necessitates treatment as well as prevention.
A recent Cochrane review and meta-analysis of family-based
interventions targeting overweight or obese children concluded
that such interventions may deliver ‘clinically relevant’ reductions
in body mass index (BMI).6 However, most studies in this review
were based on small, homogeneous samples and restricted
research settings. This raises concerns about generalisability
across all population groups (for example, low socioeconomic
circumstances and minority ethnic groups) and implementation
contexts, leaving the questions of ‘what works for whom and in
what circumstances?’ largely unanswered.6 This is important
because interventions have the potential to maintain, reduce or
generate health inequalities