A landmark study led by the University of Sydney has found no evidence that family-based early obesity prevention programs, such as home visits from health professionals or community parent groups, improve overall body mass index (BMI) in young children.
Published in The Lancet , the study was led by Dr Kylie Hunter from the Faculty of Medicine and Health as part of the TOPCHILD collaboration with multiple scientists including those at the University Medical Center Rostock and Flinders University .
Early weight is a strong predictor of future weight trajectory, with one in four children in Australia living with overweight or obesity by the time they start school.
"We found that early parent-focused obesity prevention programs did not improve BMI in children," said Dr Kylie Hunter, lead author and research fellow at the NHMRC Clinical Trials Centre and the Charles Perkins Centre .
"To shift the dial, we need to stop putting the onus on families alone. Governments, health officials and local authorities must show stronger leadership and commitment to addressing the social and environmental drivers of obesity."
Assessing the impact of childhood obesity prevention programs
The scientists analysed data from 31 international studies evaluating different types of family-based childhood obesity prevention programs commencing during pregnancy up to the age of one.
Of these 31 international studies, the researchers focused on 17 studies, which assessed children's BMI at the age of two, after the obesity programs had concluded.
The academics found that despite the range of interventions employed there was no meaningful difference in the BMI of children in families who participated in any of the programs compared to those who did not.
The interventions analysed in the study aimed to help parents build healthy habits for their children, focusing on diet, breast-feeding, physical activity, sleep and screen time. They were delivered in a variety of ways including home visits from health professionals and peer educators, community parent groups or via mobile apps.
Recognising the limits of family-based health interventions
With a third of children and adolescents worldwide forecast to live with overweight or obesity within the next 25 years , researchers say programs are being undermined by societal factors beyond families' control, especially those in lower socioeconomic groups.
Dr Hunter said: "It's hard to make healthy choices when unhealthy options are cheaper, easier, and more heavily advertised. We must address the broader environments where children eat, learn and play - making healthy choices easier for everyone, regardless of where they live."
The programs analysed in the study were conducted in countries such as Australia, the UK, Norway, Belarus, Brazil, the US and Sweden and lasted from two days to 39 months.
"We must address the broader environments where children eat, learn and play - making healthy choices easier for everyone, regardless of where they live."
Dr Kylie Hunter
Structural change key to obesity prevention
The researchers emphasised that the programs studied were well-designed and delivered by passionate and skilled professionals, but argued that without wider systemic change, both health professionals and parents were fighting a losing battle.
"The first phase of life is challenging for many families", said co-author Professor Anna Lene Seidler from the German Center for Child and Adolescent Health at the University Medical Center Rostock in Germany and affiliate at the University of Sydney.
"Parents may feel overwhelmed and lack the time, resources and stability to implement healthy behaviours without broader structural support."
The researchers warn that focusing solely on parents to make changes may also widen health inequalities.
"Families most affected by childhood obesity - often those in lower socioeconomic groups - are also the least likely to access or benefit from these programs, while families in higher socioeconomic areas, who already meet many health recommendations, are more likely to be reached," said Dr Hunter.
About the TOPCHILD Collaboration
The TOPCHILD Collaboration is a global initiative that unites more than 70 researchers from 47 institutions, contributing original data to create the largest early childhood obesity prevention database to date, encompassing nearly 30,000 children.
Research
Hunter, Kylie E, Seidler, Anna Lene, et al., 'Parent-focused behavioural interventions for the prevention of early childhood obesity: results of the TOPCHILD systematic review and individual participant data meta-analysis' (The Lancet, 2025)
DOI: 10.1016/S0140-6736(25)01144-4
Declaration
Dr Kylie Hunter and Professor Anna Lene Seidler received grant funding for this study from the National Health and Medical Research Council (NHMRC). Dr Hunter received travel funding from the EPOCH-Translate Centre of Research Excellence from 2023-2025.
