But when talking about obesity, people often fail to see the wider context that shapes our food options, and instead focus solely on individual behaviour. That’s a problem for those of us who want to promote longer, healthier lives, because when the issue is defined purely as one of poor personal choices, people think that’s just the way it is. They are less likely to see the need for the policy changes required to fix it.

This summer we’ve been working to share our research on the way people think and communicate about obesity in the UK, and how this should inform Nesta’s approach in seeking to halve its prevalence among adults by 2030. Our focus groups this summer reflected findings we’ve seen in earlier research: that when you ask the public what causes obesity, the first things that come to mind are poor individual choices and a lack of willpower – there’s a view that people just need to eat less and move more. When you ask about possible solutions, many feel the only way to create change is through improved education on food and nutrition – more cookery classes in school, for example.

However if you delve a little deeper, talk to people for a little longer, many can also see the truth of the matter – that inequality plays a major part. That if you’re on a low income it can be harder to buy and cook enough nutritious food for the whole family. That if you’re a shift worker, the food that’s within reach at unsociable hours may not be the healthiest. People tend to be unsurprised by stats which show that poorer neighbourhoods have five times the number of fast-food outlets compared with well-off ones, and that those same neighbourhoods have little green space.

But this deeper understanding isn’t top-of-mind for most people, and in the main they default to thinking that, ultimately, anyone can be healthy if they want to be.

This is why we need to forge a new narrative, one which stresses that what surrounds you helps to shape you. That where you live and your level of income can either limit or expand your available options, and make it easier or harder to be healthy. That food manufacturers, retailers and the government can – and should – change our food environments so that affordable healthy options are within everyone’s reach.

At FrameWorks we’ve spent the last four years exploring how people think about obesity and how we can discuss it differently. We have tested and developed a new way to talk about childhood obesity: first by uncovering deeply held attitudes on the issue, and exploring which beliefs were helping or hindering change; and then through qualitative and quantitative research to identify the communication tools that could shift thinking, bringing those more helpful mindsets to the foreground. We’re now building on this research with Nesta to examine the wider issue of obesity and food environments, and how we can alter the conversation to improve the nation’s health.

Our research suggests five shifts that will help build support for action, which I’ll explore here.

When we lead by talking about what this issue is fundamentally about – boosting our health – people are more willing to listen to what we have to say.

Our research shows that when we start by talking explicitly about weight or obesity, there is very little support for policy changes – for example the introduction of a tax on foods high in sugar and salt, of the kind proposed by this year’s National Food Strategy. But framing the conversation around health avoids activating blame and judgement. And when we talk about the potential of policies and interventions to improve health – rather than just tackle poor health – we inspire support for solutions.

People can see that poverty and obesity might be linked, but they sometimes struggle to explain why. And when we can’t explain something, we fall back on the stories that already feel familiar to us – in this case, that some people make poor choices, perhaps because they are insufficiently educated to know better.

When we take the time to explain how and why obesity happens, not only do we increase understanding, we build support for solutions. For example, it helps to explain that over a million people in the UK live in ‘food deserts’ – which means they don’t have a supermarket close by and must either pay for transport to buy food or rely on more expensive and less healthy convenience stores. Armed with that knowledge, it’s easier to appreciate that a solution might be to change the shops in our communities and what they sell, making healthier food more accessible.

We need to join the dots to explain how poverty restricts our options, and how where we live can shape our opportunities to eat well.

The right metaphor offers a new way to think about an issue. Metaphors present a strong mental picture and can make complicated concepts simpler to grasp.

We tested a range of metaphors to see which help people understand more about the food system – where we can buy food locally, what’s in it, and how it’s marketed to us. We found that when we compared this to a system of rivers – suggesting for example that junk food is flowing freely but that there’s barely a trickle of healthy options – it helped people to appreciate how our environment shapes health. Unprompted, some in our focus groups even adopted the metaphor themselves.

In practice this means talking about our neighbourhoods being flooded with junk food, and that we need to stem the tide of fast-food shops on our high streets. It’s about showing how our lives are saturated with unhealthy food, and explaining why we need to improve the flow of healthier options.

A word of warning on contexts: people strongly reject messages that suggest we have no agency when it comes to our weight. We need to be clear that the environment surrounding us can make it easier or harder to be healthy – without suggesting that it’s the only thing that determines our health.

We’ve found that people are often fatalistic about obesity and struggle to see how things could get better. To combat this, we need to be explicit that the trend is reversible and put forward specific solutions and ways they can be achieved. Those solutions need to feel commensurate with the scale of the problem.

We must demonstrate that we can limit the number of fast-food shops in our neighbourhoods and end the marketing of junk food to children. Explain how government can regulate so that manufacturers have to improve their recipes and make food healthier. And describe how we can redesign our workplaces, schools and communities so that a healthy option is always within reach, no matter where we live or how much money we earn.

Changing the way we talk and think about an issue takes time, practice and collaboration. But getting it right has the power to unlock a new public conversation, greater support for action and meaningful change to improve the nation’s health and wellbeing. That’s something worth talking about.