Helping people to understand the risks of obesity can nudge them away from unhealthy behaviours (Source:

It’s been almost ten years since Cass Sunstein and Richard Thaler published Nudge, their seminal book distilling decades of behavioral research into straightforward ideas for policy design and application. David Cameron and Barack Obama were both fans of this approach and, as a result, set up the renowned ‘nudge’ units in Downing Street and the White House. Both are now out of the spotlight, but it seems that ‘nudge’ isn’t going to budge any time soon – the Behavioural Insights Team are expanding their services around the world and behavioural approaches to policy and development challenges are now becoming standard practice.

One area ripe for more behavioural experimentation is public health. Many debilitating health conditions are exacerbated by lifestyle factors. Employing behavioural insights to move people away from unhealthy behaviours should result in better health outcomes for individuals and lower healthcare costs for society. So, what does this mean for the obesity crisis? Changing someone’s mind with appeals to their rational, cognitive thought is a difficult challenge. Estimates suggest that as little as 28% of our behaviour is shaped by our conscious intentions, with the rest guided by a combination of cues from our immediate environment, mental heuristics and our emotions. Nobel laureate Daniel Kahneman describes this as the conflict between our ‘system one’ brain, responsible for reflexive, automatic thought processes, and our ‘system two’ brain, where reflective, deliberative thinking takes place. If these theories hold true – and increasing experimental evidence suggests they accurately account for how people make decisions – an interesting question for policymakers is whether we can take advantage of ‘system one’ thinking to combat rising obesity rates.

Applying behavioural science to obesity reduction

On the face of it, the treatment and prevention of obesity appears to be the perfect testbed for practical application of behavioural science because of the drivers of the condition: over-eating and under-exercise. Below, I introduce three ways through which behavioural insights could be applied to obesity reduction programmes:

  1. Communicate obesity risks with saliency:

A wave of economics and psychological research suggests that people don’t understand risks when they are presented in a numerical way. Rather than describing the health risks of obesity using the probability of negative health outcomes like heart attacks and diabetes, campaigns should help people understand the risks with simple, salient communications. An example of this already in practice is the Heart Age calculator, which helps users understand their risk of cardiovascular disease without using abstract statistics. The calculator combines physiological measures with lifestyle factors to tell a user how old their heart is. A smoker with high blood pressure, for example, will have a heart age higher than their biological age. Conveying this information triggers an emotional response shown to be more effective in inciting behavior change than standard approaches. Similar communication methods could be employed to make the risks of obesity more salient and encourage people to transition to a healthy weight.

The Heart Age calculator helps people understand their heart health without using abstract statistics and probabilities, which many people disregard (Source:
  1. Overcome present-bias to encourage healthy behaviours:

Jerry Seinfeld reminded us that people focus on their present desires rather than the future implications of their behaviour, and social scientists have demonstrated this empirically, too. We need to bear this in mind when communicating the risks of obesity. Rather than focusing on abstract health consequences, campaigns should focus on lifestyle consequences in later life. For example, rather than saying that an obese person is more likely to have a heart attack, messages could focus on how an obese person is less likely to be able to play with their grandchildren in their retirement. This would help people understand how the consequences of their behaviour in the present will impact their lives in the future in a salient and engaging way. Policymakers should experiment to test the efficacy of different messages in overcoming present-bias in health decision making to work out what works best for different demographics.

  1. Override emotion with choice architecture:

Understanding how emotions influence behaviour gives policymakers the opportunity to shape the context in which people make decisions to override the effect of these emotions. Thaler and Sunstein refer to this as part of “choice architecture.” Cafeteria and supermarket design are great examples of how manipulating choice architecture can be put into practice. Hungry customers are in a ‘hot’ mental state, keen to sate their hunger with whatever captures their attention. Putting healthy foods at the entrance results in more people choosing these over the unhealthy foods – they are the easiest choice for those whose mental capacities are clouded by emotions. Lab and field studies have shown that employing choice architecture at supermarket check-outs – swapping sweets and chocolates for healthy snacks – encourages healthier snack patterns among consumers. These hypotheses are already being tested in the UK, where supermarkets including Lidl and Tesco no longer place unhealthy items at their check-outs. Policymakers could consider legislation that necessitates supermarkets and restaurants to offer healthy options presented in such a way to encourage consumers to pick them over unhealthy options.

The three recommendations, incorporating insights from behavioural science, will help policymakers overcome the heuristics that lead many people to continue with the behaviours that take a heavy toll on their health, with serious, sometimes fatal, consequences.

If you’d like to read a version of this article with a fuller discussion of the behavioural science theories that informed my policy recommendations, make sure to get in touch!

Joshua Eyre is a 1st year MPA candidate at LSE. Prior to LSE, Josh completed a Bachelors degree in history at University College London and worked at salt communications, where he developed campaigns around public health and responsible business.

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