Dieters are encouraged to turn-up to their slimming club more regularly if they sign a contract with themselves, a new study suggests.
A researcher from Brunel University London asked participants of a free, council-run slimming club to sign a contract committing themselves to turn up for 11 weeks and meet their weight loss goals. They found that those who signed the ‘commitment device’ were more likely to attend regularly and to complete the programme than those who did not. The findings can be used to tackle attitudes and behaviours that might not deliver long-term health and wellbeing.
“A ‘commitment device’ is any rule or strategy we use to influence our own future behaviour, when we know that we might set out to do 'the right thing' but not follow through when the time comes,” said Dr Manu Savani, a Lecturer in Public Policy at Brunel, who led the study.
“Thinking about good health behaviours, there are lots of things we know will help prevent longer term health issues, such as staying physically active, drinking in moderation, not smoking, and eating well. So we set ourselves health goals. But we often find there is a gap between our goals and our actual behaviours.”
The study - published by the Journal of Behavioural and Experimental Economics - asked 97 of 197 participants of Camden Council’s ‘Shape Up’ weight loss programme to sign a semi-formal written contract which pledged them to attend for the full 11 weeks. The study also collected data on the participant’s age, gender, diet, previous exercise experience and health attitudes.
The findings show that those offered the commitment contract had higher attendance and completion rates, and the contract was especially effective for those who reported more short-term health attitudes at the beginning of the study. However, the research states there was no evidence that signing the contract directly affected weight loss.
“Commitment contracts are a type of 'nudge', and like other nudges they have relatively small effects compared to more powerful policy tools such as taxes,” said Dr Savani.
“The commitment contract I tested did not lead to a direct impact on weight loss, however it did get participants in the Shape Up programme to attend more and to complete the course, and this additional engagement is hoped to support them on their weight loss journeys”.
“The research confirms that 'nudge' style policy instruments should not be seen as a silver bullet or a substitute for existing weight loss interventions, however, they can help with more modest behaviour change goals such as taking part more actively in a group-based programme, which might be the first step towards weight loss success.”
This study highlights the contribution behavioural science research can have on approaches to health improvement.
Dr Savani’s published research, Can commitment contracts boost participation in public health programmes?, can be found in the Journal of Behavioural and Experimental Economics
Simone McNichols-Thomas, Media Relations
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