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date: 14 May 2021


  • Roger ShrimptonRoger ShrimptonTulane University, Department of Global Community Health and Behavioral Sciences


Malnutrition is caused by consuming a diet with either too little and/or too much of one or more nutrients, such that the body malfunctions. These nutrients can be the macronutrients, including proteins, carbohydrates, and fats that provide the body with its building blocks and energy, or the micronutrients including vitamins and minerals, that help the body to function. Infectious diseases, such as diarrhea, can also cause malnutrition through decreased nutrient absorption, decreased intake of food, increased metabolic requirements, and direct nutrient loss. A double burden of malnutrition (both overnutrition and undernutrition) often occurs across the life course of individuals and can also coexist in the same communities and even the same households. While about a quarter of the world’s children are stunted, due to both maternal and young child undernutrition, overweight and obesity affects about one in three adults and one in ten children. Anemia, most commonly due to iron deficiency, is also affecting about a third of women of reproductive age and almost half of preschool children. Around 90% of nations have a serious burden of either two or three of these different forms of malnutrition.

Malnutrition is one of the principal and growing causes of global disease and mortality, affecting at least half of the world’s inhabitants. Programs for tackling maternal and child undernutrition have gained impetus in the last decade with a consensus developing around a package of effective interventions. The nutrition-specific interventions, mostly delivered through the health sector, are directed at immediate levels of causality, while nutrition-sensitive interventions, directed at the underlying and basic levels of causality are delivered through other sectors such as agriculture, education, social welfare, as well as water and sanitation.

Less consensus exists around the interventions needed to reduce overnutrition and the associated non-communicable diseases (NCDs), including diabetes, high blood pressure, and coronary heart disease. Prevention is certainly better than cure, however, and creating enabling environments for healthy food choices seems to be the most promising approach. Achieving “healthy diets for all,” by reducing consumption of meat and ultra-processed foods, as well as increasing consumption of fruit and vegetables, would help control rising rates of obesity and reduce NCD mortality. Adopting such healthy diets would also greatly contribute to reducing greenhouse gas emissions: the agriculture sector is responsible for producing a third of emissions, and a reduction on livestock farming would contribute to reducing global warming. Public health nutrition capacity to manage such nutrition programs is still widely lacking, however, and much still needs to be done to improve these programs and their governance.


Malnutrition is caused by consuming a diet with either too little and/or too much of one or more nutrients, such that the body malfunctions. Nutrition science is relatively young, with most of our knowledge about food and nutrition being gained since the early 20th century (Mozaffarian, Rosenberg, & Uauy, 2018). The early history of nutritional discoveries concerned deficiencies of vitamins and minerals and was largely considered completed by the 1950s. But then the problems of overconsumption and excesses started to appear and the population-level dimensions of consuming an inadequate diet as well as the life-course dimensions of malnutrition were realized. Increasingly most countries experienced a double burden of malnutrition, both overnutrition and undernutrition, which became manifest in communities, households, and even the same individuals across the life course. Furthermore, while diet has become the biggest risk factor for disease and mortality across the globe, the food system is having an increasingly negative impact on the environment. While the numbers of undernourished decreased considerably in the postwar years, since 2015 they have started rising again due to the increases in natural disasters, most likely caused by climate change (United Nations, 2019). This article will attempt to illustrate these concepts and explain both the curative and the preventive interventions that can be used to control malnutrition and help protect the environment, thus contributing to the survival of the planet.


The macronutrient fats, carbohydrates, and proteins, were largely discovered in the 19th century during investigations into the chemistry of metabolism and calorimetry (Carpenter, 2003). In the 18th century Lavoisier had shown that exhaled air contained carbon dioxide, which was formed from the reaction between oxygen (present in the air) and carbon from the organic molecules inside the organism. In the middle of the 19th century Justus Liebig discovered that proteins, carbohydrates, and fats were oxidized in the body of animals, and subsequently Max Rubner, the energy physiologist, determined the energy content to be 9 calories per gram for fats, and 4 calories per gram of both carbohydrates and proteins (Lusk, 1932).

Energy sufficiency is measured in adults by the body mass index (BMI), which is weight (in kilograms) divided by height (in meters) squared. A BMI of less than 18.5 is considered underweight, higher than 25 overweight and over 30 to be obese, although there are some regional differences (Nuttall, 2015). In young children, energy deficiency is measured as wasting, which is inadequate weight for height, with minus two standard deviations of the WHO growth standard used as the cut-off (De Onis, Monteiro, Akre, & Clugston, 1993). Infectious diseases, such as diarrhea, also cause undernutrition and stunting (inadequate height for age) in children through decreased nutrient absorption, decreased intake of food, increased metabolic requirements, and direct nutrient loss. The window of opportunity for preventing stunting is the first one thousand days, starting in pregnancy and ending at 2 years of age (Shrimpton et al., 2001). Severe Acute Malnutrition (SAM), defined by a very low weight for height (below −3z scores of the median WHO growth standards), or by the presence of nutritional edema, requires urgent treatment to survive. Early research into the severe forms of childhood malnutrition had considered that kwashiorkor was primarily due to protein deficiency and marasmus to energy deficiency, but modern treatment of SAM allows the majority of such cases to be treated at home with one standard type of ready-to-use therapeutic food (Trehan & Manary, 2015).

The micronutrients include vitamins and minerals that help the body to function; these were largely discovered in the 20th century (Carpenter, 2003). The water-soluble vitamins include Vitamin C and the Vitamin B complex (thiamine, riboflavin, niacin, pantothenic acid, pyridoxine, biotin, folate, and cobalamin). Scurvy is the disease resulting from prolonged vitamin C deficiency, which was once common among sailors on long voyages, until in 1747 James Lind famously conducted a trial of different treatments for sailors with scurvy. Only citrus fruits were effective in treating the disease, which led to British sailors having limes in their rations, and hence to their being called “Limeys.” It was only in the early 20th century that ascorbic acid was isolated and shown to be the anti-scorbutic agent. The Vitamin B complex supports metabolism and contributes to the body’s ability to produce energy in multiple ways. Specific deficiency diseases include beriberi for thiamine, pellagra for niacin and anemia for folic acid and cobalamin (B12). Good sources of B vitamins include meats, legumes (pulses or beans), and whole grains. Cereal flours are often fortified with B vitamins to replace those lost in the milling process. Although adequate intake of all vitamins is important, due to the transient nature of water-soluble vitamins, regular intake is required to avoid deficiency.

Among the fat-soluble vitamins, vitamin A is required for the maintenance of normal mucous membranes and for normal vision. It occurs naturally only in foods of animal origin, such as liver, butter, whole milk, and egg yolks, but the body converts certain carotenoids, especially β‎-carotene, to vitamin A. Carotenoids are present in dark-green, leafy vegetables and in yellow and orange vegetables and fruits. Vitamin D promotes intestinal absorption of calcium and phosphorus and influences bone mineralization, causing rickets if deficient. It occurs naturally only in animal foods such as liver, butter, fatty fish and egg yolks, and is also formed by the action of sunlight on the skin. Vitamin E is an important antioxidant that protects body tissues, including polyunsaturated fatty acids from oxidative destruction in cell membranes. Vitamin K is needed in the liver for formation of several blood clotting factors. Fat-soluble vitamins are stored in the body for long periods of time and pose a greater risk for toxicity than water-soluble vitamins.

Mineral deficiencies negatively affect billions of individuals worldwide, imposing a heavy burden on well-being and economic productivity. Deficiencies in iron, zinc, and iodine have the largest negative impact on public health. Iron deficiency is associated with anemia, decreased work capacity, decreased cognition, and increased susceptibility to infection. Zinc deficiency is associated with reduced growth, impaired immunity, and decreased resistance to infection. Iodine deficiency is associated with mental deficiency and brain damage, infant mortality and miscarriages, as well as thyroid hormone-related abnormalities. Animal protein foods are the best sources of zinc and iron, and, since the mid-20th century, iodine is most commonly obtained from iodized salt.

During the early years when the nutrients were first being discovered the main push for guidance on being well nourished was to establish the recommended daily intake (RDI) of nutrients. Many separate expert meetings were held by the World Health Organization (WHO) and the Food and Agriculture Organization (FAO) of the United Nations (UN) to decide on the recommended dietary intakes (RDIs) of energy, of carbohydrates, of fats, and of vitamins and minerals, and these were summarized at a joint FAO/WHO meeting in 1974, and then updated in 1998 (FAO, 2001). The intakes of the essential vitamins and minerals, including vitamins A, C, D, E, and K, the B vitamins, calcium, iron, magnesium, zinc, selenium, and iodine were all included in the review. The recommended nutrient intake (RNI) was the daily intake which meets the nutrient requirements of almost all apparently healthy individuals in an age- and sex-specific population group. Upper tolerable nutrient intake levels (ULs) were also established for some nutrients, defined as the maximum intake from food that is unlikely to pose risk of adverse health effects from excess in almost all apparently healthy individuals. As always, the recommendations were to be implemented through a “balanced diet and wide variety of foods,” in recognition that there is “no assurance of complete coverage of all required nutrients.” This RNI approach formed the basis of nutrient-profiling methods for systems of food classification and labelling (WHO, 2011). It also allowed food companies to market “better for you” products, with the reformulation and fortification of processed foods.

Maternal and Child Undernutrition

Undernutrition causes nearly half of global deaths in children aged under five years (Black et al., 2013). Globally some 52 million children are wasted, 155 million children stunted, 462 million adults underweight, and 264 million women of reproductive age affected by iron-deficiency anemia. In 2012 the World Health Assembly approved the Comprehensive Implementation Plan on Maternal Infant and Young Child Nutrition (MIYCN) with six global nutrition targets to be achieved by 2025. These included reductions in child stunting and wasting, maternal anemia, and low birthweight and increases in breastfeeding (WHO, 2014). The technical solutions for achieving these MIYCN goals and targets exist, including nutrition-specific and nutrition-sensitive interventions that are cost-effective and backed by evidence.

Nutrition-specific interventions directed at the immediate level of causality can help reduce maternal and child undernutrition, especially if delivered through the health sector with community outreach in order to reach the poorer segments of the population at greatest risk (Bhutta et al., 2013). Estimates are that at 90% coverage of the ten evidence-based nutrition-specific interventions can reduce deaths in children under 5 years old by 15%. The interventions include folic acid supplementation, multiple micronutrient supplementation, calcium supplementation, and balanced energy protein supplementation of women of reproductive age and during pregnancy, as well as exclusive breast feeding (0–6 months), adequate complementary feeding (7–23 months), vitamin A supplementation (6–59 months), preventive zinc supplementation, and management of SAM in infants and young children. Due to changes in immunization and disease patterns since the late 20th century, high-dose vitamin A capsules seem to be less effective, and some consider their periodic distribution through campaigns a waste of resources (Mason, Greiner, Shrimpton, Sanders &Yukich, 2015). Including multiple micronutrient supplements in the package of health and nutrition interventions delivered to mothers during pregnancy not only contributes to reducing maternal anemia, but also increases birth weight and early child growth and development (Shrimpton, Huffman, Zehner, Darnton-Hill, & Dalmiya, 2009). Where growth-monitoring programs exist, their potential should be maximized by strengthening the nutrition counselling elements and combining with other health-intervention channels such as immunization for the convenience of caregivers, and ensuring consistent message delivery (Ashworth, Shrimpton & Jamil, 2008).

Nutrition-sensitive interventions hold great promise for supporting nutrition improvements and boosting the scale, coverage, and benefits of nutrition-specific actions (Ruel et al., 2013). Nutrition sensitive programs draw on complementary sectors such as agriculture, health, social protection, early child development, education, as well as water and sanitation, to affect the underlying determinants of nutrition, including poverty, food insecurity, and scarcity of access to adequate care resources and to water and sanitation services. Ways to enhance the nutrition-sensitivity of programs include improved targeting, using conditions to stimulate participation, strengthening nutrition goals and actions, and optimizing women’s nutrition, time, physical and mental health, and empowerment.

Achieving reductions in maternal and child undernutrition requires more than just technical know-how however (Baker et al., 2018). It also demands political commitment for the sustained mobilization of national and subnational political systems, policy processes and resources for improved nutrition. It is essential to enroll the support of political leaders, parliamentarians, and administrative elites and to mobilize civil society coalitions to ensure that programs are adequately funded.

Overnutrition and NCDs

Globally, the proportion of overweight and obese adults increased by about a third from 1980 to 2013, such that almost 40% were so affected, with increases occurring in both high- and low-income countries (Ng et al., 2014). Furthermore, the proportion of overweight children under five is 5.6% and increasing, while stunting and wasting persist (UNICEF, WHO, World Bank. 2019). NCDs are the leading cause of mortality worldwide, responsible for 70% of global deaths (WHO, 2013). The three main NCDs are cardio-vascular diseases (CVDs), cancers, and diabetes, and the burden of these diseases is rising disproportionately among lower-income countries and populations. Dietary factors, especially obesity, are among the main causes of NCDs. WHO Member States agreed a global action plan for the prevention and control of NCDs in 2013 (WHO, 2013).

The fat content of the western diet has increased in the last century and typically exceeds the recommended level of less than 30% (WHO, 2003). In addition, the quality of dietary fat has decreased, and the omega 6 to omega 3 ratio is ten times what it was in the early 19th century (Simopoulos, 2008). This is principally due to the consumption of meat (chicken and beef especially) from animals that are grain-fed instead of grass-fed. The balance of omega-6 : omega-3 fatty acids has been considered an important determinant in decreasing the risk for coronary heart disease, although it is increasingly recognized that that it is the omega-3 component that is most beneficial (Harris, 2018).

During the 1970s it had been proposed that refined carbohydrates, especially sugar and a low intake of dietary fiber, were major factors in the causality of CVDs (Yudkin, 1972). These ideas were eclipsed however, by the belief that an excess intake of saturated fats was the key dietary factor for CVDs, after several large cohort studies concluded that dietary fat was a likely risk factor (Keys et al., 1986). In 1980, the US government issued its first Dietary Guidelines, which subsequently shaped the diets of hundreds of millions of people. The most prominent recommendation was to cut back on saturated fats and cholesterol. In the 21st century, however, the pendulum swung in the opposite direction, and saturated fat is understood to play a much smaller role in causing CVDs than was previously believed, while the role of sugar, whole grains, and cereal fiber have assumed a much more prominent position (Temple, 2018).

What we eat is increasingly recognized to be the major risk factor for the global burden of disease, with six of the top ten risk factors being food- and nutrition-related, including dietary risks, high blood pressure, child and maternal malnutrition, and overweight and obesity (Ng et al., 2014). High intake of sodium, low intakes of whole grains and fruits were the leading dietary risk factors for mortality and disease globally in 2017 (GBD 2017 Diet collaborators, 2019). Furthermore, what is eaten is increasingly recognized to be as important as how much is eaten for promoting weight gain (Shrimpton, Bazzano, & Mason, 2017). The main drivers of weight gain in the United States include consumption of potato chips, potatoes, sugar sweetened beverages (SSBs), together with a negative association with the intake of vegetables, whole grain, fruits and nuts. The underlying cause of this weight gain is the consumption of ultra-processed foods (UPFs), which are characteristically ready-to-consume industrial formulations of homogenized cheap ingredients obtained from high-yield crops, notably sugars and syrups, refined starches, oils and fats, and protein isolates (Monteiro & Cannon, 2019). Such formulations are made to look, smell, and taste good by use of sophisticated combinations of flavors, colors, emulsifiers, sweeteners, thickeners, and other additives that have a cosmetic function. The downside of UPF, is their high glycemic index, which enhances insulin resistance linked to adult-onset diabetes (Raj, Okoseime, Rees, & Owens, 2009). An increase in UPF consumption has been shown to be associated with an overall higher mortality risk among adults in France (Schnabel et al., 2019), and the United States (Kim, Hu, & Rebholz, 2019) and with cardiovascular disease mortality in the United Kingdom (Moreira et al., 2015).

One of the major consequences of consuming the typical “western diet,” which is low in fiber and high in sugar and protein, is a reduced diversity of the gut bacteria, called the “microbiome.” The microbiome is increasingly recognized for its potential to mediate many of the chronic inflammatory diseases, including colorectal cancer, irritable bowel syndrome, autoimmune disease, and obesity (Makki, Deehan, Walter, & Backhead, 2018). A high-fiber diet produces a healthy gut microbiota, associated with increased diversity and functions including the production of short chain fatty acids, which have many beneficial effects, including helping to maintain gut barrier function. This helps to prevent the translocation across the gut lining of bacterial products that may increase systemic inflammation.

In 1995, the FAO and WHO convened a joint consultation to establish the scientific basis for developing and using Food Based Dietary Guidelines (FBDGs) (WHO, 1996). The recommendation was that each country should develop their own FBDG, which should be based on, and aim to improve, existing dietary practices and prevailing diet-related public health problems, rather than be based on nutrient requirements and recommended intake levels. Selected recommendations for nutrient intakes were also reviewed. It was proposed that desirable nutrient intakes generally be expressed in terms of nutrient density per 1000 kcal in the diet, since all family members tend to consume similar diets and nutrient intakes of individuals are thus proportional to the energy each consumes. Almost 90% of the 119 countries that reported to WHO in 2016 had FBDGs (WHO, 2018). Dietary guidelines were disseminated through media, during campaigns, though the health system, and in schools. Over half of the countries had specific food guides visualized in the form of food pyramids, healthy plates, or various other shapes based on the national context. Adherence to the Dutch dietary guidelines was reported to be inversely associated with 20-year mortality in a large prospective cohort study (van Lee et al., 2016). In Denmark, adherence to national FBGDs was found to be associated with a lower rate of stroke (Hansen, Overvad, Hansen, & Dahm, 2018).

Physical activity plays an important role in the prevention of obesity in childhood and adolescence and reducing the risk of obesity in adulthood (Hills, Street, Soan, Mokhtar, & Byrne. 2013.). For weight loss, better results are achieved in the long term when diet and physical activity are combined (Johns, Hartmann-Boyce, Jebb, Aveyard, & Behavioural Weight Management Review Group, 2014). Insufficient physical activity is a leading risk factor for NCDs and walking enough to meet physical activity guidelines (30 or more minutes of moderate activity on 5 or more days per week) can produce a 30% lower risk of CVDs, compared with those who do not walk regularly. The WHO global action plan for the prevention and control of NCDs included a global target to reduce physical inactivity by 10% by 2020 (WHO, 2013). In 2010, nearly a quarter of adults, and over four-fifths of adolescents did not meet the WHO’s physical activity recommendations, with women, girls, and older people less active than men, boys, and younger people.

The Double Burden of Malnutrition

The double burden of malnutrition is characterized by the coexistence of undernutrition along with overweight, obesity, or diet-related NCDs, within individuals, households and populations, and across the life -course (WHO, 2017). The double burden of malnutrition can manifest at three levels and in two temporal dimensions. Firstly, the commonest double burden at the individual level is iron-deficiency anemia together with overweight/ obesity in women. The double burden can also occur across the life course of an individual, as, for example, in an overweight adult who was previously stunted during childhood. Secondly at the household level, when a mother is overweight and her child is stunted, as typically occurs in low- and middle-income countries (LMICs). Finally, at the population level, be it community, town, or country, there may be the coexistence of both undernutrition, such as wasting or stunting in children, and overnutrition, including overweight and obesity and diet related NCDs in adults. While the rates of undernutrition are declining in many LMICs, overnutrition rates are increasing.

The causes of the double burden of malnutrition relate to a sequence of epidemiological changes known as the nutrition transition, the epidemiological transition, and the demographic transition (Shrimpton & Rokx, 2012). The nutrition transition refers to the shift in dietary patterns, consumption, and energy expenditure associated with economic development over time, often in the context of globalization and urbanization. The epidemiological transition refers the changes in overall population disease burden associated with increased income, and with a shift away from infectious diseases to increasing rates of NCDs. The demographic transition relates to the shift in population structure and lengthening life spans, with increasing proportions of older people and, hence, decreasing proportions of younger people. In LMICs these processes have been accelerated, such that these three transition processes have been condensed and superimposed, leading to increased overlap and coexistence.

Consequences of these transitions include, as an example, vitamin D deficiency in elderly populations of high-income countries (HICs), a group whose members are also often overweight or obese. Around a half of the elderly in the United Kingdom have been shown to have inadequate vitamin D status, for example (Aspell et al., 2019). In old age the absorption mechanisms for vitamin D from food become less effective, and exposure to sunlight is often limited with most time spent indoors. Inadequate vitamin D status is increasingly recognized to affect not only musculoskeletal health but also a wide range of acute and chronic diseases (Holick, 2008). Finland has successfully improved the vitamin D status of its population by fortification of commonly used foods (Raulio et al., 2017)

Nutrition program efforts often overemphasize behavioral explanations and encourage health promotion to favor lifestyle intervention rather than tackling structural factors (Caraher & Coveney, 2004). As societal influences on food systems increase, programs need to address the wider issues of who controls the food supply, and thus the influences on the food chain and the food choices of the individual and communities. Policy actions to promote healthy diets cannot just focus on information-based approaches that will help the public make better-informed choices (e.g. media campaigns, dietary guidelines). In addition to these, more structural approaches are needed, such as fiscal measures and restrictions on advertising. The food industry is a massive business sector, with ten big food and beverage companies generating revenues of well over US$1 billion a day. Together they are part of an industry valued at more than US$7 trillion, larger than the energy sector and representing roughly 10% of the global economy (OXFAM, 2013). In 2018, the regulation of marketing of food and non-alcoholic beverages to children was only implemented in 40% of countries (WHO, 2018).

In order to tackle the double burden of malnutrition across the life course a range of policy interventions and programs are needed to address the overall food environment, and concerted efforts are needed from the many sectors, including health, education, agriculture, industry, social protection, and water and sanitation, as shown in Figure 1 (Shrimpton, Mbuya, & Provo, 2016). As an example, ensuring that the food environment in schools promotes healthy diets is an essential, and this should not only include healthy meals in the canteen but the absence of vending machines and “tuck shops” full of SSBs and UPF snacks. Across the globe just over a half of countries provide meals in schools, while only a half have any sort of standards or rules for the foods and beverages available, and only 60% include nutrition education in the school curriculum (WHO, 2018).

Social protection schemes can be made conditional on the target population getting other social services. Brazil provides an example of how social security payments for 11 million poor families across Brazil, made through a decentralized cash transfer program called “Bolsa Família,” are conditional on pregnant mothers getting prenatal care, and having their children vaccinated and attending school (Lindert, Linder, Hobbs, de la Brière, 2007). The supply of prenatal services and of vaccines is also ensured by the Family Health Program, which provides comprehensive primary health care services to the poorest areas in 95% of all municipalities, covering over 55% of the population, or more than 85 million people (Harris & Haines, 2010). In the five years up to 2010, the proportion of Brazilian children under 5 years old who were underweight fell by 67%, while over 75% of women received seven or more antenatal consultations, and vaccine coverage for diphtheria, tetanus, and pertussis (DTP) in children less than 1 year old was greater than 95% in most municipalities.

Figure 1. Orchestrating the various sectoral actions needed to ensure optimum nutrition across the life course (Shrimpton, Mbuya, & Provo, 2016).

With orientation from health ministries, finance ministries can levy taxes on unhealthy food and beverages. In the United States there is evidence that applying modest taxes (10–30%) on unhealthy foods (SSBs, unprocessed red meats and processed meats), as well as similar levels of subsidies on healthy foods (fruit, vegetables, whole grains, nuts and seeds), produces a significant reduction in CVDs and diabetes, that are more pronounced among the poorer and least-educated segments of the population (Penalvo et al., 2017). Although taxation alone will not solve the burden of diet-related ill health, it will make an important contribution to shifting both industry and consumer behavior in the right direction (Wright, Smith, & Hellowell, 2017).

Healthy Diets for a Healthy Planet

Feeding 9–10 billion people by 2050 and preventing dangerous climate change are two of the greatest challenges facing humanity (Smith et al., 2013). The three pandemics of obesity, undernutrition, and climate change have been termed “The Global Syndemic,” affecting most people in every country and region worldwide (Swinburn et al., 2019). These three pandemics co-occur in time and place, interact with each other to produce complex sequelae, and share common underlying societal drivers. Human activities are estimated to have caused approximately 1.0°C of global warming above pre-industrial levels, and global warming is likely to reach 1.5°C between 2030 and 2052 if it continues to increase at the this rate (IPCC, 2018). With the five warmest years on record happening during the past five years, and the 20 warmest occurring over the past 22 years, a consistent warming trend could not be clearer. While over-reliance on fossil fuels has certainly contributed greatly to this, the modern industrial agriculture system has also played an important and under-recognized part.

Global warming is caused by greenhouse gas (GHGs) emissions, which trap the heat of the sun in the atmosphere. At least a quarter of global GHG emissions come from the agriculture sector (Tubiello et al., 2014), a close second to the electricity and heat-production sector. Within the agricultural sector GHG emission come mostly from the cultivation of crops and livestock, and from deforestation. Livestock alone contributes at least 18% of annual global GHG emissions (FAO, 2006), which is greater than the transport sector. But even if the fossil fuel sources of CO2 are reduced, that will not be enough on its own to reach the targets of the United Nations Framework Convention on Climate Change agreed in Paris in 2015. If the food system is also fixed however, the two together could certainly help achieve these targets.

The modern industrial agricultural system is also causing a massive loss of biodiversity. Since the dawn of civilization 83% of all wild mammals have been lost, and in the last 50 years alone, the populations of all mammals, birds, reptiles and fish have fallen by an average of 60% (WWF, 2018). Since the 1900s, some 75% of plant genetic diversity has been lost as farmers worldwide have deserted their multiple local varieties and landraces for genetically uniform, high-yielding varieties (FAO, 2004). A global study of 5,000 fisheries, representing 80% of reported fish catches, found that two-thirds were being overfished, and stocks were declining (Costello et al., 2016). More than 40% of insect species are declining and one-third are endangered (Ceballos, Ehrlich, & Dirzo, 2017); the rate of extinction of insects is eight times faster than that of mammals, birds and reptiles. The total mass of insects is falling by a precipitous 2.5% a year, suggesting they could vanish within a century. The expansion of industrial agriculture has contributed to the reduction and elimination of wild forest and grassland species of plants and animals. Unless we change our ways of producing food, insects will go down the path of extinction in a few decades, and the repercussions this will have for the planet’s ecosystems will be catastrophic to say the least.

Transforming to healthy and sustainable diets by 2050 will require substantial dietary shifts, including a greater than 50% reduction in the global consumption of unhealthy foods such as red meat and sugar, and a greater than 100% increase in the consumption of healthy foods such as nuts, fruits, vegetables, and legumes (Willet et al., 2019). Unless technological changes and dedicated mitigation measures are introduced, the negative environmental effects of the food system could increase by 50–90% between 2010 and 2050 (Springmann et al., 2018), reaching levels that are beyond the planetary boundaries that define a safe operating space for humanity.

While there is increasing clarity about what needs to be done to tackle the Global Syndemic, getting action to transform the food system is recognized to be an enormous challenge. The slow progress in tackling any of the three components of the Global Syndemic, is largely due to “policy inertia.” This collective term includes the combined effects of inadequate political leadership and governance to enact the policies needed, as well as strong opposition to those policies by powerful commercial interests, and the lack of demand for policy action by the public. The identification of double-duty or triple-duty actions to transform the food system, making it both healthy and sustainable, is simultaneously a challenge and an advocacy opportunity. For example, if eating less red meat produced by the industrial agriculture system is shown not only to reduce the release of greenhouse gases, but also to reduce the likelihood of NCDs, then it is a double-duty action.

Removing the subsidies provided by governments to make industrialized meat cheap, would make it more expensive and so reduce its consumption, thus freeing up funds to support more sustainable forms of agriculture, making it a triple-duty if not a quadruple-duty action.

Public Health Nutrition Capacity

Public Health Nutrition (PHN) comprises the promotion and maintenance of the nutritional health of populations by optimizing the nutritional status of communities, sub-populations and whole populations (Hughes, 2003). The implementation and/or delivery of most PHN interventions is by front-line health professionals, including doctors, nurses, midwives, and community health workers. Increasingly they will have to provide support to other non-health actors, including teachers and agriculture extension workers as examples. Evidence from the Landscape Analysis Country Assessments (LACA) carried out in a dozen LMICs indicated that many countries had the willingness to act, but none had the capacity to act at scale (Nishida, Shrimpton, & Darnton-Hill, 2009). The task of building capacity to act in nutrition at both national and district levels is indeed great.

A workforce structure has been proposed in order to assure the quality of a workforce for scaling up nutrition programs in LMICs, as is shown in Figure 2 (Shrimpton et al., 2016). At the lower level of the health system, typically at district level, capacity building is proposed for the front-line health professionals through in-service training, which should be largely provided by a public health nutritionist. In addition to this, a district PHN manager should also use a nutrition information systems to ensure that district nutrition services are working well. Community-based health and nutrition workers along with their next-level supervisors form the most important part of human resource input into PHN programs and are the prime targets of the PHN manager (Shrimpton, 2002). In-service training of these PHN managers is urgently needed if effective public health nutrition programs are to be scaled up (Delisle et al., 2017).

Figure 2. Capacity building and the structure of the Public Health Nutrition Work Force (Shrimpton et al., 2016).

Addition of the ecological dimensions to PHN, promoting the health of the planet as well as its human populations, will also require that the nature of nutrition programs becomes even more multisectoral. The importance of coordination mechanisms at the highest political level to facilitate collaboration and policy coherence across sectors beyond health and agriculture cannot be overemphasized. In 2016 just a third of countries reported having nutrition-coordination mechanisms in high government offices, such as that of the prime minister, or president (WHO, 2018).

The UN General Assembly has proclaimed 2016–2025 the United Nations Decade of Action on Nutrition (WHO/FAO, 2018). The decade is an unprecedented opportunity for addressing all forms of malnutrition. It sets a timeline for implementation of the commitments made at the Second International Conference on Nutrition (ICN2) to meet a set of global nutrition targets and diet-related NCD targets by 2025, as well as relevant targets in the Agenda for Sustainable Development by 2030. These include in particular, Sustainable Development Goal (SDG) 2 (end hunger, achieve food security and improved nutrition and promote sustainable agriculture) and SDG 3 (ensure healthy lives and promote wellbeing for all at all ages). The UN Decade of Action on Nutrition, led by WHO and FAO, calls for policy action across six key areas, including: 1) creating sustainable, resilient food systems for healthy diets; 2) providing social protection and nutrition-related education for all; 3) aligning health systems to nutrition needs, and providing universal coverage of essential nutrition interventions; 4) ensuring that trade and investment policies improve nutrition; 5) building safe and supportive environments for nutrition at all ages; and 6) strengthening and promoting nutrition governance and accountability, everywhere. Failure to deliver on these commitments will not bode well for the future of mankind or for the planet.