Can peers help the obesity crisis? Or is it all just too confusing?


By Sarah Bell

Obesity in young people is a major public health concern associated with a range of health problems. Globally over 170 million children are estimated to be overweight.

Energy balance, the relationship between ‘energy in’ and ‘energy out’, plays a key role in obesity. Unfortunately, physical activity (energy out) declines with age, particularly for girls, and adolescents become more independent in their eating behaviours (energy in), which can be positive or negative! Since behaviour patterns that develop during adolescence are likely to influence long-term behaviours, this is a critical age.

It’s hard to escape the obesity problem, but what can we do about it?

One approach to addressing obesity in young people has been investigated in the AHEAD (Activity and Healthy Eating in ADolescence) study, by DECIPHer researchers at the University of Bristol.

What was the aim of the study?
The aim of AHEAD was to test whether it would be possible to use peer education to increase physical activity and healthy eating in adolescents. The study adapted a peer education approach developed in ASSIST (A Stop Smoking in Schools Trial), which was shown to be effective in reducing the numbers of adolescents who started smoking. This approach is informed by diffusion of innovations theory, which argues that changes in behaviour of a social group are initiated by ‘early adopters’ who are often popular or well-regarded individuals.

How was this done?
Six schools were involved in the study: three that received the AHEAD training (intervention schools) and three that didn’t (control schools). All Year 8 students (aged 12-13 years) in intervention schools were asked to complete a questionnaire to identify influential students in their year group. These potential ‘early adopters’ were invited to train as ‘peer supporters’, to use everyday interactions with their peers to try and encourage physical activity and healthy eating. They were given two days of training away from school, provided by specialist trainers, and four further follow-up sessions in school. 

What were the key messages of the AHEAD intervention?
The AHEAD training programme provided key messages for the peer supporters to deliver to their peers.

The key physical activity messages were to:

 The key healthy eating messages were to:

  • increase breakfast consumption;
  • increase fruit and vegetable intake;
  • reduce the amount of fizzy drinks, sugar, salt and fat they consumed.

How were diet and physical activity measured? 
To see whether the AHEAD intervention increased pupils’ physical activity and healthy eating, data relating to these were collected before the AHEAD intervention (baseline) and seven months later.

Behavioural questionnaires were used to find out how often participants consumed particular foods, and accelerometers were used to measure physical activity. Accelerometers are worn round the waist and continuously monitor physical activity over multiple days capturing ‘real time’ intensity and duration of movement.

What did the research tell us?
A mixture of quantitative and qualitative research methods led us to conclude that it was possible to adapt the approach taken in ASSIST to focus on physical activity and health eating. We were able to recruit schools and deliver the intervention in a way that fitted in with the school timetable and curriculum. We were also able to recruit and train the peer supporters and keep them involved in the study. 

However, we found no clear or consistent evidence that the AHEAD intervention improved physical activity or eating behaviour. There were no differences in the reported consumption of breakfast, fruit and vegetables, or fizzy drinks, sugar, salt and fat between the intervention and the control schools. 

Was this peer-led approach appropriate?
There were two reasons that this approach to encouraging healthy eating and physical activity may not have been suitable:
  • the complexity of the messages involved;
  • the workload, resources and related costs of implementing the training programme. 

AHEAD was based on two key messages: eat healthily and be more active. The peer supporters had to ‘diffuse’ the key messages to their peers. We concluded that focusing on both physical activity and healthy eating at the same time appeared too complex for informal diffusion through peer networks.

We also recognised that even if the messages were successfully passed on by peer supporters to other pupils, this may not be sufficient – young people may need more parental and school support to enable them to change their behaviour. Additionally, the ‘obesenogenic environment’ we live in, which encourages the consumption of high-fat, high-sugar food and discourages exercise, may work against the messages of the AHEAD intervention.

The AHEAD study suggests we can’t just rely on young people alone to spread messages about physical activity and healthy eating to their peers in an attempt to address the rapid increase in obesity. Whether we blame the food industry, our physical environment, our genes, or people around us, it is clear more needs to be done to tackle the obesity problem.

Just remember…

This piece draws on findings from the following article: 

Bell S, Audrey S, Cooper A, Noble S, Campbell R. ‘Lessons from a peer-led obesity prevention programme in English schools’ Health Promotion International 2014. First published online: 6 April 2014. doi: 10.1093/heapro/dau008

Sarah Bell is a research associate at DECIPHer, based at the University of Bristol. She is currently undertaking a PhD on physical activity and emotional wellbeing in young people.

Infographic source: The Weight of the Nation

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