Childhood overweight and obesity is an issue that affects over 350 million children and adolescents worldwide. In many countries, more than a quarter of young people have to contend with being overweight or obese.
This is a phenomenon that applies equally in developing countries because as countries develop economically, one sees a dramatic increase in the prevalence of childhood obesity. Thus, economically emerging countries must contend with undernutrition and overnutrition at the same time. In India, 26 million children suffer from wasting, yet it also has the second highest number of obese children in the world after China.
The underlying factors in this transition are lifestyles that facilitate access to unhealthy foods, in combination with a physical environment that promotes low levels of physical activity both in and out of work. This is frequently accompanied by a transition from rural to urban living. In conditions of undernutrition in prenatal life and in early childhood, individuals are more likely to become obese when exposed to these factors.
The conventional story is that obesity is a result of poor choices which implies that children or their parents are to blame for gaining weight. This is not only incorrect but destructive. It is more useful to focus on our environments and how we can make them the health-creating places they could be.
It is also very difficult for anyone with obesity to speak out about their experiences. This needs to be encouraged, because changing deeply entrenched prejudices does not happen overnight. It needs to be understood also that in some developing countries, there exist inherent biases in the system that may keep obesity from being addressed, such as a belief that increased weight is associated with wealth and reduced weight with illness including HIV.
Countries from both developing and developed worlds are taking decisive action to counter the obesity epidemic with measures such as sugar taxes, restrictions on front-of-pack labelling and a focus on breastfeeding. This is not about blaming individuals or controlling them but changing the environment to make healthy choices easier.
After all, losing weight - and crucially, keeping it off - is far from straightforward. There are strong physiological mechanisms that make it difficult for an individual to lose excess weight once it has established itself.
Far more should be done to develop effective strategies for managing obesity. These strategies must acknowledge that it is, unsurprisingly, hard to get adolescents to turn up for treatment or change their behaviour.
Furthermore, adolescents are acutely aware of their body image. Yet simultaneously, they are bombarded with media messages - almost entirely outside parental or school control - that encourage unhealthy eating. Obesity can be a struggle both mentally and physically. Experiencing obesity in childhood can be depressing.
Whether we are talking about obesity, climate change or the future of technology, adolescents are powerful agents for social change. As the next generation of parents, workers and decision-makers, young people should be empowered to shape where they grow up.
World leaders have an unprecedented opportunity to effect real change during a high-level meeting at this year's UN General Assembly, which will focus on non-communicable diseases, like diabetes, cancer and heart disease, largely driven by the obesity epidemic. But will they hear what children are asking for?
The Public Health Institute of Norway, supported with a grant from the European Commission have launched CO-CREATE, a €10m, five-year programme to prevent overweight and obesity which includes adolescents in all aspects of the programme. This is the kind of inclusive programme that has real potential and if successful, is something that could be replicated in countries around the world.
In India, the Delhi High Court has issued restrictions on the sale of junk food in and around schools, while in the UK the advertising of junk food is not allowed within 100 metres of school gates. These measures need extending to protect children in all environments.
Global leaders need to hear the voices of all children and speak out - and more importantly act - on their behalf. Children deserve to be healthy, and they deserve to be heard.
Tim Lobstein is Policy Director for the World Obesity Federation based in London, UK and Adjunct Professor at the Public Health Advocacy Institute of Western Australia, Curtin University, Perth.
Any views expressed in this article are those of the author and not of Thomson Reuters Foundation.