Behavioural science can help governments reduce obesity

02 November 2015 | Cancer prevention, Policy

David HalpernDavid Halpern is Chief Executive of The Behavioural Insights Team (BIT).

Prior to this, he was the founding Director of the Institute for Government and Chief Analyst at the UK Prime Minister’s Strategy Unit. David is the author of Inside the Nudge Unit: How small changes can make a big difference.


Michael HallsworthMichael Hallsworth is Director of Health & Tax at The Behavioural Insights Team (BIT).

Unofficially known as the ‘nudge’ unit, BIT was the world’s first government institution dedicated to the application of behavioural sciences. BIT started life as part of the UK government & is now jointly owned by the UK Government, Nesta, and its employees.


It’s widely agreed that obesity is a significant contributing cause of cancer. And, while reducing global obesity rates is a complex issue, much progress could be made if we found effective ways of helping us eat less. However, in order to do this, we need to have a more realistic understanding of how we eat – and a recent new initiative from Australia shows how this could be done.

Amount we eat not based on conscious choices

We generally think of eating as a matter of choice and self-control – we decide what to eat, and how much to eat. However, the crucial insight from the behavioural sciences is that consuming food is often not a wilful act; it is a “mindless” response to our environment. We unthinkingly eat food if we are exposed to it. For example, a famous study served soup to participants either in standard bowls or in ones that looked the same, but slowly kept refilling (in other words, they could never be emptied). The study found that the group with refilling bowls ate 73% more soup than the others. A recent evidence review has also confirmed that larger portions and larger items of tableware lead to more food or drink being consumed.

Interestingly, these experiments show that people do not become aware they have eaten more, don’t feel fuller than people who ate a standard portion, and they don’t end up eating less food later. So, the amount we eat is not based on our conscious choices, or even our hunger levels. Yet we think we are making deliberate choices about eating (although we think that others may be susceptible to being influenced). This belief means we often try to control our eating through simply applying willpower. This generally does not work: for example, dieters often end up eating more.

Evidence often does not inform policy

More worryingly, the evidence of mindless eating often does not filter through into public awareness or policy formulation, which means we may not be tackling the real cause of the problems.

Innovative approach: let members of the public decide

What can we do to ensure this kind of evidence has greater impact? The Behavioural Insights Team has been working with Victoria Health in Australia to get people exploring these issues through a 100-strong “deliberative jury”. The idea here was to have randomly-selected, members of the population come together to form a Citizens’ Jury and probe experts, industry and government, in order to try to work out what – if anything – government should do to reduce obesity. The idea was that, when the Citizens’ Jury had a chance to explore the evidence in depth, they might come up with new, more effective policy approaches. In a dramatic conclusion to the process, the Citizens’ Jury voted by standing or sitting to indicate their position on each of the proposals, which needed 80% agreement to make it into the final report.

Citizens’ Jury in action

The jury received over 63 detailed submissions, which it spent six weeks deliberating online before coming together on 17-18th October. The resulting 20 proposals, which have just been published, are a striking combination of the radical and practical, including:

  1. A ban on junk food and beverage marketing to children under 16 years
  2. Strengthening the power of local communities to decide on food outlets in their area
  3. ‘Red’ category (the most unhealthy) foods should not to be displayed at points of sale
  4. Asking for a 20% tax on sugar-sweetened drinks (this proposal goes further than any government in the world to date)
  5. A government-mandated health star labelling programme
  6. Fast-food exclusion zones around schools, sporting clubs, youth and community centres

This wasn’t a group of public health experts, but a group of ordinary citizens weighing the evidence they heard from multiple sources, and against the implications for people’s lives as consumers, parents, and citizens. A steering group made up of state and city government, industry, third sector and Victoria Health has now set itself a few weeks to respond. Many people across the world will await what happens next with great interest.

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David Halpern, Michael Hallsworth | 02 November 2015

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