Why a Global Convention to Protect and Promote Healthy Diets is timely

In view of the 10th anniversary of the WHO Global Strategy on Diet, Physical Activity and Health^{( 1 )}, which encouraged governments to develop and implement nutrition policies, Consumers International and the World Obesity Federation recently launched a set of recommendations towards a Global Convention to Protect and Promote Healthy Diets^{( 2 )}. In addition, a high-level Commission on Ending Childhood Obesity^{( 3 )} has been set up by the WHO to specify and reach consensus on the approaches likely to be the most effective for obesity prevention in different contexts around the world. These initiatives are very timely, as progress on developing and especially implementing policies to reduce obesity and diet-related non-communicable diseases (NCDs), since the launch of the Global Strategy in 2004^{( 1 )}, has been largely insufficient. As dietary risk factors have recently overtaken tobacco as the leading risk factor for disease^{( 4 )}, a similar powerful tool as the WHO Framework Convention on Tobacco Control (WHO FCTC)^{( 5 )} is needed to help reduce the global burden of obesity and diet-related NCDs.

The growing problems of obesity and diet-related NCDs

No country has succeeded in significantly reversing the surge in obesity or diabetes. The proportion of adults with a body mass index of 25 kg/m² or greater increased from 28·8 % to 36·9 % in men, and from 29·8 % to 38·0 % in women, between 1980 and 2013^{( 6 )}. In this issue, studies from Ireland^{( 7 )} and Colombia^{( 8 )} show an increasing prevalence of adult overweight and/or obesity over time, and in Colombia a faster increase among lower socio-economic groups was observed^{( 8 )}. In Peru, the trend in overweight among children aged 0–6 years remained stable in the period 1991–2011, but rose among boys in the richest wealth quintile^{( 9 )}. Polat et al.^{( 10 )} found a relatively high prevalence of hypertension among young Turkish children and a significant correlation between hypertension and obesity.

Dietary risk factors increasingly contribute to the surging global burden of obesity and diet-related NCDs^{( 4 )}. Molina-Montes et al. show in this issue that adherence to the Spanish dietary guidelines is linked to significantly lower odds of obesity^{( 11 )}. However, globally, there is a clear gap between population diets and dietary guidelines. According to Lynch et al.^{( 12 )}, average consumption of fruits and vegetables among children in ten European countries was only between 220 and 345 g/d and did not reach the WHO population goal of ≥400 g/d in any of the participating countries. In addition, eating out is more common, and adults’ fast-food and full-service restaurant consumption was associated with higher daily total energy intake and poorer dietary indicators in the USA^{( 13 )}.

Government and food industry efforts towards achieving WHO targets

Comprehensive actions by major players, such as governments and the food industry, will be needed to improve food systems and population diets and to achieve the WHO targets of halting the rise in obesity and diabetes and reducing NCDs by 25 % by 2025^{( 14 )}. Governments mainly seem to have focused on single nutrition policies, rather than comprehensive approaches, and still seem to favour educational rather than food system approaches to obesity prevention^{( 15 )}.

Some strong policies have been developed but not implemented, such as the portion size cap in New York City^{( 16 )} or comprehensive restrictions on food marketing to children in various countries. Some policies were overturned shortly after implementation, such as the ‘fat tax’ in Denmark^{( 17 )}.

Voluntary initiatives by the food industry do not seem to work well without strong government leadership and threat of legislation. Despite all the supermarket chains surveyed having signed up to the Government’s ‘responsibility deal’ in the UK, Horsley et al.^{( 18 )} show in this issue that the overwhelming majority of products to which children are exposed at the checkouts of those supermarkets are unhealthy. Relatively few countries (such as South Africa and Argentina) have set mandatory maximum levels for sodium in a comprehensive range of food products and even fewer have set such levels for other nutrients of concern, such as saturated fats. According to Kanzler et al.^{( 19 )}, the salt content of convenience and ready meals in six countries in continental Europe mostly exceeded 1·8 g/100 g, which is 30 % of the upper recommended daily intake level. In an article published in last month’s issue of Public Health Nutrition, Hobin et al.^{( 20 )} reported big differences across five countries in levels of nutrients of concern in ‘kids’ menu’ food items offered by four leading multinational fast-food chains. These examples show that there is plenty of room to reduce promotion of unhealthy foods to children and to improve the composition of food products. Strong government leadership is critical to guide food industry efforts in those areas, and governments need to set clear population intake targets and food composition targets for nutrients of concern.

The importance of a Global Convention to Protect and Promote Healthy Diets

Some countries have recently taken thoughtful actions to improve their food system; some best-practice exemplars of government nutrition policies from around the world are nicely highlighted and summarized in a flyer distributed during the most recent World Health Assembly by the World Cancer Research Fund^{( 21 )}. Recommended measures in the proposed Convention to Protect and Promote Healthy Diets^{( 2 )} include restriction of food marketing, improving the provision of nutrition information, requiring reformulation of unhealthy food products, raising standards for foods provided in public institutions and using economic tools to influence consumption patterns. A Global Convention such as the WHO FCTC^{( 5 )} for tobacco control should help to lift the levels of action by governments to reduce obesity and diet-related NCDs and decrease the influence of the food industry on policy development. Additionally, accountability for obesity and NCDs prevention at the national level, including measurement, review of progress and stimulation of action, will be essential to ensure progress^{( 22 )}. In this issue, Kraak et al.^{( 23 )} propose a four-step accountability framework to guide government and food industry engagement to address unhealthy food environments as part of a broader government-led strategy to address obesity and diet-related NCDs. In addition to a Global Convention for Healthy Diets and stronger accountability mechanisms at the national level, the new WHO high-level Commission on Ending Childhood Obesity^{( 24 )} could be the strong advocate needed to support critical efforts by governments and the food industry to reduce obesity and diet-related NCDs globally.