When the United Nations launched its new Sustainable Development Goals in 2015 - the blueprint to guide national agendas and political policies for the coming 15 years and the successors to the Millennium Development Goals - a major shift in thinking occurred.
Included in this list of 17 goals and 169 targets for investment, focus, research and action, was a new way of thinking about a long-established challenge. Reflecting the transforming global burden, the narrative of nutrition evolved in a fundamental way.
Moving from a sole focus on undernutrition alleviation and food security, this new agenda unveiled and embedded a more holistic approach - one that included food quality, equity and food systems, and broke down traditional policy and implementation silos with a central focus on malnutrition in all its forms.
Today, approximately 462 million adults worldwide continue to be underweight, while almost two billion are overweight or obese. An estimated 41 million children under the age of 5 are overweight or obese, while 159 million are chronically undernourished. In low- and middle-income countries with emerging economies, almost five million children continue to die of undernutrition-related causes every year, yet simultaneously these same populations are now witnessing a rise of childhood overweight and obesity - increasing at a rate 30% faster than in richer nations.
In the context of a rapidly and dramatically changing global nutrition landscape, influenced by economic and income growth, rapid urbanisation and globalisation, human diets and diet-related epidemiology have seen significant shifts in recent decades.
Once accepted as near-linear processes of nutrition and associated epidemiological transitions - processes by which economic development, dietary patterns and resulting epidemiology transform from a predominant burden of undernutrition, including micronutrient deficiency, to overweight and obesity - nations, households and even individuals are now faced with a much more complex nutrition paradigm.
Communities still struggling with growth-stunting rates of up to 30% are now witnessing a rise in obesity and related disease. Anaemia is affecting individuals who are also obese. Children are experiencing wasting while older family members struggle with overweight.
This is the epidemiological and clinical phenomenon known as the double burden of malnutrition.
In short, this double burden of malnutrition describes a coexistence of both undernutrition, including wasting, growth stunting and deficiencies in micronutrients (including iron, folate and vitamin A), with overweight and obesity - and resulting nutrition-related noncommunicable diseases (such as diabetes, cardiovascular disease or cancers). This dual health challenge is witnessed at all levels - from the individual to the population - and affects health across the entire life course from pre-birth to death.
Moreover, this relationship between undernutrition and overweight and obesity is more than simply a coexistence. Reflected in the epidemiology and supported by science, undernutrition early in life - and even in mothers - may predispose to overweight and noncommunicable diseases later in life. Overweight in mothers is also associated with overweight and obesity in their offspring. Rapid weight gain early in life may predispose to long-term weight excess. These are just some of the examples of biological mechanisms increasingly understood to be important drivers in the global burden of malnutrition.
With profound and interdependent challenges, we must seek, identify and scale new, integrated solutions. Complex in nature, addressing this double burden will require coordinated action across the life course. Reflecting the key recommendations of the Rome Declaration on Nutrition, low-hanging fruits do exist that can be implanted today and led by primary care physicians.
The first is to recognise, champion and address the strong links between all forms of malnutrition and poverty. Even in high-income countries, lower socio-economic status is a risk factor for obesity, diabetes, stroke, mental illness and nutrition insecurity. Realising that these challenges are linked to economic hardship is an important first step in championing for solutions.
With more and more evidence emerging, the importance of maternal nutrition on the risk of malnutrition and associated diseases in both mother and child has never been more evident. Acknowledging the links between maternal malnutrition - either undernutrition or overweight and obesity - and the intergenerational burden of these conditions is key. Investment in maternal nutrition is essential in protecting the future health of families and communities.
A third key message is that win-win actions exist to effectively address all forms of malnutrition - and many of them are cost-effective.
One example is breastfeeding. Exclusive breastfeeding for a period of at least 6 months from birth is associated with a reduced level of undernutrition and obesity in childhood, adolescence and early adulthood. It is also associated with nutrition-related health benefits for the mother. Ensuring the supports and systems are in place that make breastfeeding possible for new mothers, and delivering evidence-based education on breastfeeding benefits, are just two examples of measures that will lead to population-level nutrition improvements.
While undernutrition and excess adipose tissue - or overweight and obesity - can be reduced to a conceptual imbalance between the number of calories consumed and the number used by an individual, the determinants of bodyweight are much more complex.
In reality, it is a combination of biological, environmental and behavioural factors that determine bodyweight - a dimension that is particularly important and apparent when considering the global scale of the burden of malnutrition.
Key to addressing malnutrition is addressing the following factors: regulatory changes to reverse the transition in global food systems that has led to near-universal access to cheap, processed and unhealthy foods that are higher in saturated fats, salt and sugar than traditional or local diets; changes to the urban and built environments which currently discourage physical activity or active travel, or hinder access to fresh or healthy foods; and policy to further limit the advertising of unhealthy foods - a practice that has led to these foods and alcohol becoming an accepted part of many cultural and social activities globally.
The change to a more holistic conceptualisation of malnutrition may seem subtle, but as we embark on a United Nations Decade of Action on Nutrition, the potential public health benefits could well prove transformational. Dietary risk factors, together with inadequate physical activity, account for almost 10% of all global disease and disability.
If we can move beyond traditional silos and focus efforts on shared drivers, solutions and treatments to all forms of malnutrition, we will be truly kicking goals.
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Dr Alessandro Demaio is a staff member of the World Health Organization in Geneva. He alone is responsible for the views expressed in this publication and they do not necessarily represent the decisions or policies of the WHO. Dr Demaio is co-founder of the not-for-profit project NCDFREE.
This article was originally published with the Medical Journal of Australia.