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Fruit, vegetables, pulses and nuts

Health problems like cancer, diabetes and heart disease are on the rise in many parts of the world, fuelled by unhealthy diets and a lack of physical activity, but while the advice to ‘eat less and move more’ might sound simple, many of us find it hard to do. 

Plentiful and cheap supplies of foods like salty ready-meals or sugary drinks make it difficult to make healthy choices. Designing cities and towns to suit private cars rather than pedestrians and cyclists does not encourage physical activity. At the same time, food production and transportation have a significant impact on the environment. 

These issues are the backdrop for the research of Professor Mike Rayner and his team at the Centre on Population Approaches for Non-communicable Disease Prevention (CPNP), part of the Nuffield Department of Population Health. They’re finding out how best to encourage as many people as possible to live healthier lives in an environmentally sustainable way, focusing in particular on diet. Here are just a few examples of how their work has made a difference. 

Everyone eats

‘Everyone eats and everyone has an opinion on the best diet, so it’s easy to get people interested in our work,’ says Professor Rayner. ‘In fact we already know how people could improve their health – the problem is, how do we get people to do it?’ 

Rather than devising public health campaigns, Rayner and his colleagues are focusing their attention on developing and testing policy changes that make a difference to behaviour. It is vital that any proposals are supported by high quality research, and so Rayner’s team is building a robust evidence base to show what works and what doesn’t, meaning that new policies are more likely to have the desired effects. 

As an example, he and his team gathered key evidence to support the introduction of the UK Government’s recommended ‘traffic light’ labelling system for major food retailers, helping shoppers to make healthier choices. Although the scheme isn’t compulsory and some major players have opted out, the majority of foods sold in the UK now carry the coloured labels. 

Rayner’s investigations of how unhealthy foods and non-alcoholic drinks are promoted to children have also helped to shape the legislation banning the advertising of unhealthy foods and drinks to children in the UK, which first came into effect for TV ads in 2007 and were updated in 2017 to include other media. 

He and his team have also carried out detailed analysis of the links between fast food outlets near schools and childhood obesity, finding that easy access to fast food near home rather than school may be more of a problem. 

Taxing questions

Another key area has been investigating the ideas and evidence behind the so-called ‘sugary drinks tax’ – a levy on high sugar drinks that has been imposed in a number of countries including Mexico, France and Norway. The UK joined the club in April 2018, bringing in a tax of 24p per litre on the most sugary drinks containing more than 8 grams of sugar per 100 ml, reduced to 18p per litre for beverages with 5-8 grams per 100 ml. 

Rayner and his colleagues are now part of the team evaluating the impact of the sugary drinks tax in the UK, gathering evidence to see how well it is working. Yet for every piece of evidence and policy that could make a difference to public health, Professor Rayner faces pushback from food and drink manufacturers. 

‘There’s a strong parallel here with the tobacco industry’s tactics. The sugary drinks tax has worked in Mexico, but the manufacturers deny it has had an effect and have worked to undermine it there and everywhere else governments have sought to introduce such a tax,’ Rayner explains. 

‘The work we do has to be sustained over a long period of time, and also has to be implemented by the Government, but more people are getting interested in this kind of research, so things are starting to change.’ 

Two papers have already been published on the research looking into the effects of the sugar tax in the UK. The first, led by Lauren Bandy, was sales-weighted, and showed that the amount of sugar sold in soft drinks in the UK has fallen by 29% since the introduction of the tax. A second paper, on research led by Dr Peter Scarborough, showed that overall sugar levels in soft drinks have dropped significantly. Prior to the introduction of the tax, 52% of soft drinks were eligible, while after its introduction, just 15% of soft drinks were eligible.

Saving the planet’s health

As well as looking at human health, Rayner and his team are now turning their attention to the health of the planet in relation to food production and consumption. The environmental impacts of meat and dairy farming are becoming increasingly clear – along with the negative health effects of eating excessive red or processed meat – so cutting down on these foods gets a green light in more ways than one. 

In a paper published recently in the journal Nature, Rayner and his team analysed various options for reducing the environmental effects of the food system, including dietary changes towards healthier, more plant-based diets, improvements in technologies and management, and reductions in food loss and waste. 

They found that no single change would be enough to keep the environmental impacts within all acceptable boundaries, so a combination of measures working together will be the only way to reduce the projected impact on the planet. 

‘There are some tensions between trying to have a healthy lifestyle and saving the planet, and we have a poor understanding of the relationship between environmental sustainability and health,’ he says. ‘Climate change and global warming are huge threats, but if we’re going to address them we’re going to have to compromise on some health outcomes.’ For example, Rayner points out that eating lots of exotic fruits and vegetables might be good for your health but it’s not great for the environment if they’re being flown halfway round the world before they get to your plate. 

He and his team at the NDPH are continuing to build the evidence around how best to change society in ways that benefit human health without harming the environment, from finding out whether edible insects count as a healthy food to investigating whether ‘virtual supermarkets’ are a useful tool for revealing public shopping habits. Although his current work may take some time to bear fruit in the form of legislation, Rayner feels that there is no time to lose. 

‘I think we know enough about the kinds of things that make a difference,’ he says. ‘It’s more important to be devising methods to get people to have healthier and more sustainable lifestyles now, rather than figuring out the exact details of how every intervention will help.’