Can schools be expected to solve the obesity crisis?

Posted on 1 November 2019

Schools are often seen as the first line of defence against many of society’s problems, but how easy is it to actually make a difference? IEE’s Jonathan Haslam looks at the evidence.

(This article was first published in Schools Week, Mon 21st Oct 2019)


Schools are often seen as the first line of defence against many of society’s problems. When a new issue arises, the knee-jerk reaction often is that “schools should be doing more”. Take rising obesity and the need to improve activity levels and reduce waistlines. Two recently published studies (one aimed at reducing obesity in primary, the other increasing activity levels in secondary) illustrate the problem.

The first is a randomised controlled trial of the West Midlands Active Lifestyle and Healthy Eating in School Children (WAVES) intervention*. This involved almost 1,500 five and six-year-olds from 54 primary schools, and was by no means light touch. Lasting for 12 months, it included:

  • 30 minutes of additional moderate-to-vigorous physical activity (MVPA) on each school day;
    termly cooking workshops during school time, when parents were invited to learn with their children;
  • a six-week programme to encourage healthy eating and increase physical vitality, delivered by the local professional football club;
  • information sheets supporting children and their families to be active over the summer.

Children’s measurements – including weight, height, percentage body fat, waist circumference, skinfold thickness and blood pressure – were taken when they started the trial and again 15 months and 30 months later. They were then compared with children in a control group.

At the first follow-up, the mean body mass index (BMI) score was not significantly lower for the intervention group compared with the control. At 30 months, the mean difference was smaller and remained non-significant. This intervention, then, was not successful in bringing about an improvement in young children’s weight – and presumably not in their overall routines of activity and eating.

Children become less active as they grow older, so might an approach in secondary school prove more effective? A recent study looked at the impact of Girls Active**, a programme developed by the Youth Sport Trust that provides a support framework to schools to review their physical activity, sport, and PE teaching to ensure they are relevant and attractive to all adolescent girls. It has a particular focus on 11 to 14-year-olds.

Twenty secondary schools in the Midlands participated in the trial, with ten schools receiving Girls Active and ten schools continuing with usual practice. In total, 1,752 girls aged 11 to 14 took part. The primary outcome measure (at the start, seven months, and 14 months) was MVPA, recorded on wrist-worn accelerometers. Secondary outcomes included overall physical activity, light physical activity, sedentary time, body composition, and psychosocial outcomes.

The results showed small improvements in MVPA compared with control schools after seven months, but none after 14 months. Interestingly the subgroup analysis showed that the intervention was effective at 14 months in larger schools, but caused an MVPA decrease in smaller schools. (Perhaps larger schools had the capacity to run the programme effectively, while in smaller schools it was more distracting than helpful.) There was no pattern in the secondary outcomes, and any differences were slight.

Of course these are just two studies, but both were disappointing, despite requiring substantial resources. It suggests that making a difference to these issues requires wider community involvement – not surprising, given that they are issues affected by what is occurring in the wider society, rather than in schools alone.

For schools, it is a reminder that investment in addressing these issues may not necessarily result in improvement. Reviewing the evidence of what has worked (or not) in the past is a vital first step before taking any action. Limited resources mean it is important to choose the right priorities. Shifting the dial on a particular issue takes effort, and you can’t focus on everything.


* Effectiveness of a childhood obesity prevention programme delivered through schools, targeting 6 and 7 year olds: cluster randomised controlled trial (WAVES study) (February 2018), BMJ 2018; 360:k211

** Effectiveness of the “Girls Active” school-based physical activity programme: A cluster randomised controlled trial (April 2018) International Journal of Behavioral Nutrition and Physical Activity

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