Acute malnutrition is a condition that results from insufficient intake of energy, nutrients, and/or infection over a short time period. It is caused by a decrease in food intake and/or an illness or infection. Acute malnutrition typically manifests in weight loss and is detected by measuring weight and height, or by the size of the upper arm (mid- upper arm circumference) and referred to as wasting in children less than 5 years of age and thinness in children and adolescents 5-19 years of age and adults.

Agricultural biodiversity (or agrobiodiversity) refers to the variety of plant and animal species that are used as part of food production. Many varieties are currently underutilised but highly nutritious, representing potential for improving diets.

Agronomic biofortification is an emerging technique that involves using fertilisers that contain nutrients (minerals essential for humans such as zinc, selenium, iron) to soils or on plant leaves. It has been shown to increase the content of those nutrients in the crops, in particular commonly consumed grains.

Anaemia is a condition in which the size and/or number of red blood cells or their oxygen-carrying capacity is lower than it should be for healthy functioning. Anaemia has several causes, including iron deficiency, folate deficiency, infection and inflammation among others. It is frequently cited that 50% of anaemia is due to iron deficiency, but recent studies have shown that this proportion varies across settings. Consequently, policies and programmes to address anaemia should be tailored to the specific causes. The amount (concentration) of haemoglobin, an iron-containing oxygen-transporting protein contained in red blood cells, below a cut-off point is used to diagnose anaemia.

Anthropometry refers to the study of the measurements and proportions of the human body. Common measures used include weight, height, waist and hip circumference, and mid-upper arm circumference (in children). These measures can be used to assess nutritional status when compared to values estimated to be healthy for specific age and sex groups.


Biofortification refers to the process of increasing the nutrient content and/or bioavailability of nutrients (that is, the ability of the body to absorb them) in crops through classical plant breeding techniques. Several commonly consumed foods have been developed and shown to be effective for improving nutrient intakes, including iron-rich beans and millet, and vitamin A-rich sweet potato and cassava.


Complementary feeding refers to the process that starts when breast milk is no longer sufficient to meet an infant’s nutritional needs and other foods and liquids are required, along with breast milk. Special foods are needed during this time because the amount of food consumed by infants is small, yet their nutrient needs are high. Thus, nutrient density must be adequate. The World Health Organization (WHO) recommends that complementary feeding begin at 6 months of age and continue to 18-24 months of age when children can transition to family foods. Breastfeeding is recommended to continue along with complementary feeding until two years of age and beyond.

Complementary feeding that starts too early (before 6 months of age), too late (after 6 months of age) or does not include appropriate, nutrient-dense foods is an important cause of undernutrition.


Demand creation for nutrition is creating (or activating) and sustaining desire for nutritious foods as a part of diets. This includes influencing consumer food choices at the point of purchase, whether that be fresh foods for preparation in the food or prepared foods.

Diet quality refers to the extent to which a diet meets nutrient requirements, promotes health and protects against disease. A quality diet consists of the appropriate amounts of energy, beneficial nutrients (e.g. micronutrients (vitamins and minerals), essential amino acids, and essential fatty acids), bioactive compounds (e.g. polyphenols, antioxidants, and flavonoids), probiotics (beneficial bacteria and yeasts), fibres, and low amounts of potentially harmful compounds (e.g. trans-fat, refined sugar, substances that limit the body’s ability to absorb and use nutrients) and harmful bacteria, viruses, and other parasites.

Non-communicable diseases are diseases that are not contagious, i.e. not transmitted from one person to another or by insects or other pests. Diet-related NCDs are those diseases for which poor diet quality is an important cause, including diabetes, heart disease, some cancers, among others.

Nutritious diets are those that include a variety of foods, such as fruits and vegetables, animal source foods or alternatives, legumes, nuts, seeds and whole grains. Dietary diversity has been developed as a measure of the variety of foods consumed in the diet as a simple approach to assessing a nutritious diet. Dietary diversity is measured by counting the number of food groups consumed daily. In several studies, higher dietary diversity has been shown to reflect higher nutrient intake in individuals and households. While a useful measure for its simplicity, dietary diversity does not fully capture the quality of a nutritious diet as quantities of nutritious foods consumed is not captured, and consumption of unhealthy foods is not included.

The double burden of malnutrition refers to the coexistence of undernutrition (stunting, wasting and/or micronutrient deficiency) with overweight, obesity and/or diet-related non-communicable diseases (NCDs). The term double burden has been used extensively in nutrition, without making the distinction of whether this occurs within individuals (both affecting the same person), households (affecting different people within the household) and populations (affecting different sub-groups within the population). The term “triple burden” has recently been used in some publications to highlight stunting, anaemia, and overweight, obesity, and NCDs. Stunting and anaemia are, however, only two of the many manifestations of undernutrition and highlighting these only may draw attention away from other issues that must be addressed.

Therefore, the double burden of malnutrition, which encompasses undernutrition with all of its forms and related consequences, and overweight, obesity and NCDs in all of their forms and related consequences is more appropriate.

This term was developed to refer to policies, programmes, and actions that have the ability to simultaneously reduce the risk or burden of both undernutrition (stunting, wasting and/or micronutrient deficiency) and overweight, obesity, or diet-related non-communicable diseases. Exclusive breastfeeding to 6 months of age and continued breastfeeding beyond is a good example of a double-duty action as it both prevents undernutrition in the infant and promotes long-term health.


The environmental footprint of a food item refers to the impact of production of that food on the environment. It includes greenhouse-gas emissions, land use, water use, and fertiliser and/or pesticide residues. Environmental footprints vary highly by geographic area and agricultural system, but are generally highest for animal-source foods, particularly meat and dairy – foods which are also high in many essential nutrients.

Exclusive breastfeeding is the practice of giving only breastmilk and no additional food or drink, not even water, to an infant. The World Health Organization recommends exclusive breastfeeding to 6 months of age and continued breastfeeding with appropriate complementary feeding from 6 until at least 24 months of age to promote optimal growth, health and development.


Food and nutrition security is defined as the state in which adequate food (of sufficient quantity, quality, safety and socio-cultural acceptability) is available and accessible to all individuals at all times and is consumed and utilised to ensure adequate nutritional status. By incorporating nutrient intake and the body’s ability to absorb and utilise nutrients, this concept includes an important extension to nutrition, when compared to earlier definitions of food security that placed more emphasis on avoiding hunger.

Food environment is a term used to describe the context in which individuals obtain, prepare and consume their foods. There are many different definitions of food environment, but most include some combinations of four essential elements:

  1. physical and economic access to food – meaning its physical availability and affordability;
  2. the promotion, labelling, advertising, information related to food in that context;
  3. food quality and safety;
  4. the acceptability and desirability for the consumer.

It is increasingly apparent that it is this food environment that can and has shaped food consumption patterns.

Food loss refers to losses of food that occur in the supply chain from agricultural production to the consumer. This loss can be the result of pre-harvest problems (e.g. from pests, crop diseases, and losses during harvesting itself), or post-harvest losses related to handling, storage, packing, and/or transportation. Some of the underlying causes of food loss include the inadequacy of infrastructure, such as cold storage and transport, imperfect markets, and poor credit availability. Food loss is a particularly important problem for many of the most nutrient-dense foods, such as fruits, vegetables, and animal-source foods, which tend to be perishable and easily damaged. According to the World Bank, food loss in low-income countries occurs mainly during production and processing of food, whereas in higher-income countries it occurs mainly from distribution to consumption. Food loss differs from food waste, which occurs at points of preparation and consumption.

A food supply chain refers to the processes and actors that take a food item from farm to fork - i.e. from on-farm production to the end consumer. For some foods, this encompasses many changes required to turn the raw agricultural material into the final product, for example from stalks of grain to wheat to flour to bread. This includes production, storage and handling, transportation, processing, packaging, distribution, and retail. A food supply chain becomes a food value chain when it is seen as a process in which value is added to the product at different stages. Food value chains can therefore improve food safety by removing contaminants or increase nutritional value for example through food fortification.

The food system includes all processes, infrastructure, and actors involved in all aspects of feeding a population. This includes everything from agricultural production, regulations and laws related to food, imports, processing, the inputs needed for food production and processing, distribution, marketing, sale (wholesale, retail, formal and informal markets), consumption, and disposal of food. The food system in all these aspects is what shapes the food environment.

Food waste refers to food that is safe and nutritious for human consumption but is discarded or diverted to an alternative (non-food) use, such as bioenergy or animal feed, instead of being eaten. Most food waste occurs at the retail or consumption level and differs from food loss that occurs at the points of production and processing. Food waste tends to be higher in higher-income countries. Causes include exacting preferences or standards for evenly-shaped or attractive foods, conservative “sell by” dates, inefficient or neglectful consumer or caterer practices, poor stock management, and the unconsumed portion on plates that is thrown away.

Fortification is the practice of intentionally increasing the content of a micronutrient in a food to improve the nutritional quality of the food and prevent the health effects associated with micronutrient deficiency. Large-scale (also known as industrial or mass) fortification adds nutrients to foods that are commonly consumed by a large proportion of the population at the stage of food processing.


Governance for nutrition refers to the set of laws, policies, standards, processes and actions that govern food systems, and favour food safety, and nutrition for the population in a country, or the region to which they apply. For example, “urban governance for nutrition” would encompass the process of making and implementing decisions that shape food systems to deliver better nutrition for people in cities.


Macronutrients include carbohydrates, fats, and proteins, which are components that are found in large amounts in food and are essential for life. Carbohydrates are needed primarily as a source of energy, while fats and proteins provide both energy and substances essential for body functions such as growth, muscle development and function, and many others.
Micronutrient is a general term that refers to all vitamins (e.g. vitamin A, B, vitamins such as folate, vitamin D) and minerals (e.g. zinc, iron) that are required in small amounts for a host of different processes in the body – including the healthy functioning of all organ systems, growth, development, and health. An essential micronutrient is one that must be obtained from the diet because the body cannot produce it or does so in quantities insufficient to meet needs.
A micronutrient deficiency is caused by an inadequate intake of a vitamin or mineral in the diet and/or infection/inflammation and several ailments that hinder the absorption and utilisation of nutrients by the body. Deficiencies of some micronutrients result in specific syndromes when severe. Some of the most well-known examples include rickets (vitamin D deficiency), goitre (iodine deficiency) and scurvy (vitamin C deficiency). Less severe deficiency of many nutrients also has important health and development consequences, such as impaired brain and muscle development/functioning (e.g. iodine and iron deficiency). Micronutrient deficiency has often been termed “hidden hunger” because mild and moderate deficiency may have no visible consequences. The most well-known micronutrient deficiencies include iron, vitamin A, zinc, folate, iodine, vitamin D, but several others may also be of public health importance, such as vitamin B12 (particularly among strict vegetarians), thiamine (in populations which consume a lot of polished rice), among others.


Nutrient density or micronutrient density refers to the proportional amount of nutrients contained in food per some measure of weight or volume. This is an important consideration, particularly for complementary feeding because small children have high nutrient requirements but very small stomachs. Therefore, it is important that every bite counts - i.e. that everything a child eats contains a lot of the vitamins, minerals, proteins, and essential fats needed to survive and thrive.

Nutrition refers to the “processes” through which a human being uses everything that is ingested for the purposes of maintaining life, growth and all normal functions. These processes include ingestion, digestion, absorption, as well as the transport, storage, metabolism, utilisation and elimination of food from the body. The result of these processes is reflected in the nutritional status of the individual.

The nutrition transition is a term used to refer to the shift in populations from a high burden of infectious disease and undernutrition to a high burden of overweight/obesity, and diet-related noncommunicable diseases. The nutrition transition has been occurring for many years but depends on many things in the country, including the food system, health system, infrastructure (such as water and sanitation), income, among other factors. This transition has resulted in the double burden of malnutrition in many populations.

Nutritional status refers to the state of a person resulting from the availability and utilisation of nutrients to meet biological requirements of the body. Thus, a person’s nutritional status is determined both by nutrient intake and health status, which can influence the requirements, absorption and utilisation of nutrients. Several measures are used to assess nutritional status in humans. The adequacy of nutrients consumed from food can identify risks of malnutrition by comparing dietary intake of nutrients to nutrient requirements of individuals. Measures of physical size, for example height and weight (anthropometry) are used to detect undernutrition, as well as overweight and obesity. “Biomarkers”, or measures of nutrient status in the body - usually from blood or urine samples - provide information about recent intake of nutrients, or long-term status, depending on the measure used. Biomarkers are commonly used to assess micronutrient status and diagnose micronutrient deficiency.

A nutritious food is one that in the way it is consumed and by the individual that consumes it, provides beneficial nutrients (e.g. vitamins, minerals, proteins, essential fats, dietary fibres) and minimises potentially harmful elements (e.g. anti-nutrients, high quantities of saturated fats and sugars). See also safe food.


Overweight and obesity are measures of nutritional status that identify excess weight or body fat which increases risk of diet-related non-communicable disease. They are defined by measures of body size (anthropometry), usually height and weight, compared to values that in populations have been associated with higher health risks. Body mass index (BMI), or the relationship of weight to height (weight kg, divided by height in cm squared) is commonly used to diagnose overweight/ obesity. Commonly used cut off point for overweight in adults is BMI greater than 25, and for obesity, BMI greater than 30. However, in some populations, health risks related to excess weight may occur even at lower BMI. Because the expected proportion of weight to height for children and adolescents is different than that for adults, different indicators and cut-off points are needed to diagnose overweight/obesity.


The private sector refers to that part of the economy of a country that is owned by individuals or groups rather than the state or public sector, which is made up of governments, non-governmental organisations, not-for-profit organisations, and civil society organisations. The private sector comprises businesses, including small and medium-sized enterprises whose purpose is to make money for owners or shareholders. In many countries, the private sector employs a large part of the workforce. In most countries, activities across the food system are within the private sector, while being governed by the public sector.

Public-private engagement refers to cooperation among organisations in the public sector (governments, non-governmental organisations, not-for-profit organisations, civil society organisations) and businesses that make up the private sector. For nutrition, such engagement should be guided by a common objective to improve the food system or similarly support actions that will facilitate food and nutrition security. When that cooperation is guided by a formal arrangement (contract or memorandum of understanding), it is often referred to as a public-private partnership. Such cooperation - whether formal or informal - can be instrumental in making lasting changes for nutrition but must be guided by clear and transparent principles that identify and manage potential commercial and other interests.


Safe food is that for which levels of contaminants remain below certain limits at all steps along the food supply chain, and thus avoid exposure and prevent food-borne illness. See food safety.

A small and medium-sized enterprise is a business that operates with a number of employees below certain limits. This number varies by context. Generally, small enterprises have fewer than 50 employees and medium-sized companies have less than 250 employees. SMEs are an essential part of the food system in many countries around the world. Particularly in low- and middle-incomes countries, SMEs may be providers – as producers, processers, transporters, venders – of much of the food consumed by low-income consumers.

Stunting refers to the process where linear growth is slower than expected. Every person’s height as an adult is determined by a combination of their genetic growth potential and several environmental factors that may facilitate or limit their ability to reach that potential. Nutrition is one of those environmental factors that can limit normal growth in utero and throughout infancy, childhood, and adolescence. Health and infection are also important factors in this process of growth faltering. Stunting is ascertained by measuring height compared to expected values for the child/adolescent’s age and sex. However, because an individual’s genetic potential is not known, stunting cannot be diagnosed in individuals. Rather the measure can tell us whether populations are likely not reaching their growth potential. Therefore, at a population level the rate of stunting provides a reflection of the nutritional and health status of children/adolescents in that population. The same factors that limit growth affect health and development, so in populations with a high rate of stunting, there is also higher risk of morbidity and mortality, as well as delayed child development and long-term risks for adult health.

Supplementation is the provision of nutrients, mainly vitamins and minerals, from non-food sources, such as pills, chewable tablets, powders to be dissolved in water, syrup, drops, which are called supplements. Micronutrient powders (i.e. powders containing nutrients, mostly micronutrients, that can be mixed with food immediately before consumption) have recently been referred to as “home fortification”, but this type of product is a supplement.

Sustainable diets are those that balance the environmental impacts of the food system with the need to ensure food and nutrition security for present and future generations. Ideally, they are protective and respectful of biodiversity and ecosystems, culturally acceptable, accessible, economically fair and affordable, nutritionally adequate, safe and healthy, while optimising natural and human resources. There is much focus in research and policy on sustainable food systems, and how to manage the trade-offs of meeting the needs of people and planet now and into the future. We will keep this definition updated as new developments arise.


Thinness is a form of undernutrition and refers to a body mass (weight) that is too low. In children, thinness is associated with increased risk of dying and higher risk of become ill/more severally ill. Because a person’s expected weight depends on their height, thinness can only be diagnosed in relation to height – in children using a ratio of weight to height, and in adults using the body mass index (see overweight/ obesity for explanation). In children less than 5 years of age, thinness is referred to as wasting and is a measure of acute malnutrition. In situations where weight and height measurement is not feasible, the circumference of the upper arm < 125 mm has been used to identify wasting (WHO Growth Standard 2006). Weight, particularly in children, is sometimes measured and assessed with reference only to age rather than height. When low, this is referred to as “underweight”. Its use to diagnose nutritional status in children should be avoided whenever possible as it does not distinguish between stunting and wasting.


Undernutrition is a general term used to refer to any number of conditions that result from inadequate intake of energy and/or nutrients, and/or health issues that increase requirements, or hinder nutrient absorption and/or utilisation. These include micronutrient deficiency, stunting, thinness/wasting. While the term may be useful to draw attention to the issue, it is too general and should not be used to facilitate understanding of the causes of the problem or policy and programme actions needed to address them.