Nutrient-dense foods and diverse diets are important for ensuring adequate nutrition across the life course

Significance

Many people worldwide have inadequate diets, leading to a high prevalence of malnutrition in all its forms. Several factors prevent people from accessing healthy diets, including socioeconomic and geographic factors. In this paper, we uncover the biological nutritional vulnerabilities stemming from high micronutrient needs per calorie among infants and young children, women of reproductive age, pregnant and lactating women, and older adults, particularly older women. To address these vulnerabilities and micronutrient gaps, we highlight the importance of a diverse diet that includes both plant and animal-source foods. We also present the divergent consumption patterns of animal-source foods regionally contributing to nutritional vulnerability.

Abstract

The world faces a global challenge of how to meet the nutritional needs of a diverse global population through diets. This paper defines the relative nutritional needs across each stage of the life cycle to support human health and identifies who is nutritionally vulnerable. Findings in this paper suggest that there are biological nutritional vulnerabilities stemming from high micronutrient needs per calorie in certain phases of the life cycle, particularly for infants and young children, women of reproductive age, pregnant and lactating women, and older adults, particularly older women. The paper demonstrates the role of micronutrient-dense animal-source foods and plant-source foods important in meeting essential nutrient needs to support healthy growth, development, and aging across vulnerable stages of the life cycle.

Nutrition is crucial for human development both biologically and socially. Biologically, nutrition is needed to support the growth of humans across different stages of life and prevent disease. Socially, nutrition contributes to the gains of people’s freedoms, opportunities, and well-being. Nutrition is so vital for the overall development of humans, communities, and nations that a Sustainable Development Goal, SDG2, is dedicated to ensuring that all forms of malnutrition and hunger are eliminated by 2030. As it stands currently, 148 million children under the age of five are chronically undernourished (stunted), 45 million are acutely undernourished (wasted), and 37 million are overweight (1). A recent study suggests that progress and achievements toward SDG2 have slowed or deteriorated (2).

As the world continues to undergo demographic and economic transitions, all countries worldwide now face multiple burdens of malnutrition, where populations, households, and even individuals experience both undernutrition (micronutrient deficiencies, childhood stunting, and wasting) and obesity and diet-related noncommunicable diseases (DR-NCDs) simultaneously (3). Undernutrition and DR-NCDs have been characterized as pandemics occurring against the backdrop of another pandemic, climate change. These pandemics compound and interact, creating a complex phenomenon described as a global syndemic, which has significant consequences for food and nutrition security and far-reaching impacts on human and planetary health (4).

Key to this complexity is how to meet the nutritional needs of populations through dietary intake, given the uniqueness of human requirements based on biology (e.g., sex, age, genetics, nutritional status, medical history) and other vulnerabilities (e.g., conflict, marginalization, poverty) without further breaching the safe operating space for humanity (5). Over the life cycle, women and young children are particularly vulnerable to malnutrition primarily because of their increased micronutrient needs and the immense intergenerational and developmental consequences if those needs are not met (6). Their heightened vulnerability is illustrated by 56% of preschool-aged children (372 million) and 69% of nonpregnant women of reproductive age (1.2 billion) being deficient in at least one essential micronutrient (7).

The types of diets people consume daily hold a heavy weight on nutrition outcomes (8). A central feature of a healthy diet that meets nutritional needs is one with sufficient diversity of foods rich in nutrients (i.e., “nutrient-dense” foods). Populations living in low- and middle-income countries (LMICs) and resource-constrained geographies are particularly susceptible to monotonous, low-quality diets with little diversity, increasing the risk for nutrient inadequacy (9). The consumption of low-quality diets is a critical driver of undernourishment and DR-NCDs and is responsible for one in five deaths globally (10–12).

Yet, accessing healthy diets is a hurdle for many populations. Currently, 42% of the world (3.1 billion people) cannot afford a healthy diet—a diet that meets nutrient needs and is health protective (1). That is a 6.7% increase compared to the pre-COVID-19 pandemic levels in 2019. Even before the pandemic, and even more so since the start of the Ukraine–Russia war and subsequent rising food prices, many populations have had difficulty affording healthy diets due to various macrodrivers and factors such as poverty, inequities, and social disempowerment, lack of access to markets and technology, and inadequate food supply infrastructure (13, 14). These factors significantly affect the ability of food systems to deliver healthy diets and adequate nutrition to individuals. Insufficient health services, in turn, impact individual and societal health, including increased risk of micronutrient deficiencies and DR-NCDs, reducing productive potential (15).

Nutrient-dense foods, especially animal-source foods (ASFs), are expensive in many LMICs (16). One solution is to decrease future reliance on ASFs as an essential nutritional source across the life cycle. There are further arguments for promoting reductions in ASF consumption because of their significant contribution to a changing climate and large natural resource requirements (17, 18). While it is hard to disentangle climate change from any other scientific question or pursuit in our present crisis, when meeting human nutritional needs is solely examined, what are the optimal food sources of nutrients to meet the needs of various populations across different life cycle stages?

In this paper, we define what it means to have nutritional needs across every stage of the life cycle to support human health. We also demonstrate who is nutritionally vulnerable based on their life stage, where nutrient deficiencies and inadequacies are most prominent and in which populations across the life cycle. We then present the types of foods that can fill related nutrient gaps, including both plant-source foods and ASFs. Last, we present what ASFs are consumed worldwide and where and highlight populations that could benefit from more diverse diets.

Nutrition across Stages of the Life Cycle

Nutritional status during each stage of the life cycle is met through the intake of various nutrients found in foods, sometimes complemented with biofortified crops, nutrient supplements, and foods fortified with key micronutrients. Micronutrients present in food can also be modified by how food is grown and prepared, thus impacting the nutrient bioavailability to humans (19, 20). There are additional nondietary or food pathways that influence nutritional status that will not be presented in this paper.

The requirements of both macro- and micronutrients vary by one’s age, sex, growth, physical activity levels, and development throughout the life cycle. Each life stage has distinct implications for both nutrient needs and disease risk. Certain life stages are periods of biological vulnerability (21, 22). While nutrition vulnerability can stem from biological needs, there are other important factors that impact who is and who is not nutritionally vulnerable, such as socioeconomics (education, wealth), place (location on the urban–rural continuum), sociocultural factors (values, culture, social norms), and geopolitical factors (conflict and displacement). Beyond biological vulnerability, marginalizing specific populations based on their social and economic standing (e.g., those living in poverty), which can lead to being disadvantaged within society, deepens the vulnerability of certain life stages (23–25). This section, however, centers around biological vulnerability to understand human nutritional needs independent of availability and access to healthy diets. There are specific periods of life when nutrients are needed in higher density or amounts, including during pregnancy, lactation, infancy and early childhood, and older age. While nutrition is critical throughout the life cycle for everyone, some periods of life and some individuals are particularly nutritionally vulnerable from both nutrient-density requirements and biological standpoints.

During pregnancy, nutrition is vital for placental growth, hormone and enzyme function, and nutrient and gas exchange, as well as the growth and development of fetal organs and tissues of the fetus (26). Sufficient calories, folate, vitamin D, iron, iodine, essential fatty acids including omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and fiber are critical to ensure the health of the growing fetus. A healthy, diverse diet is essential during this time, and for vegans, supplementing vitamin B12 or consuming foods fortified with vitamin B12 is critical since it is unavailable in plant-source foods (27). For the pregnant woman and mother, higher nutrient needs support antenatal, intrapartum, and postpartum health and ensure her own needs are met as the fetus’ nutrient needs are preferentially met over the mother’s (28). During lactation, nutrition is critical to support the adequate nutritional composition of breast milk (29). Furthermore, there is evidence that elevated needs for certain micronutrients (magnesium, B vitamins) are also associated with maternal mental health (30).

Core to the intergenerational cycle of malnutrition are two important life stages—pregnancy and adolescence. Pregnancy is a critical life stage for women when increased nutritional needs and maternal undernutrition can contribute to propagating this cycle. The intergenerational cycle of malnutrition occurs when undernourished mothers give birth to babies with low birth weight whose stunted growth places them at an increased risk of mortality, morbidity, and suboptional growth (31). As such, adolescence (ages 10 to 19 y) establishes the nutritional well-being of women of reproductive age. The importance of this life stage is underscored because of the growth potential and opportunity during this period—when growth hormone maturation and an increase in adrenal androgens occur. Importantly, these hormonal changes support physical development during adolescence, when 15 to 25% of final height, 50% of adult weight, and 40% of bone mass are achieved (32, 33). Body composition changes dramatically due to puberty, with increased body fat in girls (34). Nutrient needs are mostly similar for adolescent girls and boys, with a few exceptions. Adolescent boys' caloric needs are higher than girls, and during older adolescence (>13 y of age), boys have higher protein needs than girls. However, protein, specifically essential amino acids, is critical for both sexes during this life stage to support the growth spurt that occurs during this time (32). Adolescent girls have increased needs for iron primarily due to the onset of menstruation (35). Calcium, phosphorus, and magnesium needs are elevated during this life stage to support bone growth. Because of this brief period of rapid growth and the opportunity to maximize growth through adequate nutrient intake, it can be seen as a nutritionally vulnerable life stage (35).

While the life stages of women experiencing adolescence, pregnancy, and lactation are critical, women’s nutrition matters regardless of their reproductive potential. With the increased attention to adolescent girls’ nutritional needs overall combined with a high prevalence of eating disorders in this age group, as well as the high prevalence of obesity and DR-NCDs among women globally, nutrition remains vital for women across the entire life cycle (36, 37).

During infancy, the brain is still structurally developing, providing the foundation for cognitive, motor, and socioemotional skills to be used throughout the remainder of the life cycle. This is also a period of rapid and continued bone, muscle, and fat growth critical for reaching their full potential (6), including school attainment, improved future birth outcomes of offspring, and earning potential (12). Inadequate feeding practices or poor access to nutrient-dense and varied diets, as well as epigenetic programming and infectious disease burden, can instill poor brain development and growth outcomes in young children that can be lifelong (38). During this time, iron needs are high, particularly for continued brain growth. Iron-rich sources are particularly important at 6 mo when the child is introduced to complementary foods since iron requirements per calorie are higher than that at any other time in life.

Children aged 6 to 9 y experience a period of adrenarche, somatic, and cognitive development, body composition changes, and height and bone growth and mineralization. Specific nutrients of importance include an overall increase in energy needs, given higher energy expenditure, calcium, essential amino acids, vitamin D, iron, zinc, iodine, and phosphorus (39). This life stage sets up the baseline nutritional status with which a child enters the important phase of adolescence described above.

Among older adults 65 and older, nutrient requirements change with reduced metabolism, physical activity, and mobility. As people age, there is an increased risk of muscle weakness and sarcopenia characterized by muscle atrophy and loss of physical function. Previous muscle mass reserves and increased frailty predict the extent of older adults’ risk of muscle weakness and sarcopenia (40, 41). People with obesity have a higher risk of frailty, heightening the nutritional vulnerability of this subpopulation and their subsequent nutrient needs (42). While older adults need less energy overall, protein and micronutrient density needs are higher than in younger adults to prevent DR-NCDs and to minimize bone and lean muscle mass loss that occurs with the aging process (43). Micronutrients of particular importance for aging adults include calcium, Vitamins D, E, and K, potassium, and fiber (44). Protein needs are typically even higher among older adults with chronic illnesses because of their lower physiological reserves of protein which become further depleted during the onset of chronic disease associated with increased inflammation and malabsorption (45, 46). The quality of protein consumed during this life stage is important, with essential amino acids being particularly helpful in muscle protein synthesis (47). Due to their longer life expectancy, older women are at risk for developing nutritional deficiencies over a longer period, during a time that is already characterized by lower energy intake and muscle loss, thus making older women more biologically vulnerable (48, 49).

Nutrient Density Needs across the Life Cycle

Differences in micronutrient requirements, discussed above, and varying energy needs across life stages result in nutritional vulnerabilities. This can also be described based on the density of micronutrients per calorie required (i.e., nutrient density requirements), as shown in Fig. 1, and described as “nutrient density needs.” In particular, children aged 7 to 23 mo need a daily consumption that is twice as dense in iron as compared to mean global nutrient needs across all life stages. Pregnant women need 86% higher folate density, while lactating women need 70% higher vitamin A and 37% higher folate densities during the exclusive breastfeeding period.

Fig. 1.

Relative nutrient density needs by life stage and sex for six priority micronutrients. Values indicate a percentage increase or decrease from the global average micronutrient density needs across all life stages.

High relative energy requirements for children and adolescents aged 2 to 19 y signify that micronutrient density needs are below mean global nutrient density needs across all life stages for folate, zinc, and vitamins A and B12, though calcium density needs remain high to support skeletal growth. Entering puberty, adolescent girls aged 10 to 19 also show increased iron density needs (11% higher than the global mean). As energy requirements decrease with advanced age, older adults aged 65 to 79, especially older women, also show increased nutrient density needs for calcium, folate, iron, and vitamin B12.

Meeting Nutritional Needs through Food

Plant-source foods and ASFs contain complementary nutrient profiles. Plant-source foods provide the only dietary source of fiber and are optimal sources of folate, potassium, magnesium, vitamins C and E, and beneficial phytonutrients (50). Plant-source foods also contain antinutrients such as phytates, which bind to minerals like iron and zinc, hindering their absorption (20). While vastly limiting ASFs can increase the risk for specific nutrient deficiencies for certain individuals across the life cycle (51), some experts suggest that well-planned vegetarian diets are appropriate for individuals of all life stages (52). However, this is not accepted by all nutrition experts, and for infants and young children 6 to 23 mo in particular, evidence suggests vegetarian diets can increase the risk for micronutrient deficiencies and impaired growth (53).

ASFs contain unique nutrients, including heme iron, retinol, vitamin D3, vitamin B12, and beneficial compounds like creatine, anserine, and taurine. ASFs also typically contain more bioavailable zinc, vitamin B6, and protein than plant-source foods and are significant sources of DHA, EPA, and choline (17, 50). In general, ASFs contain higher quantities or more bioavailable forms of protein, omega-3 fatty acids, iron, zinc, choline, and vitamins B6, B12, A, and D, which are commonly lacking worldwide (7, 17, 54–57). While ASFs contain unique nutrients and more bioavailable forms of certain nutrients, unrefined plant-source foods (especially those without added sugars or fats), including fruits, vegetables, legumes, nuts, seeds, and whole grains, are fundamental for protecting against DR-NCDs.

As shown in Fig. 2, the optimal sources of priority micronutrients—iron, zinc, calcium, folate, and vitamins A and B12—are ASFs and dark green leafy vegetables. ASFs like organ meats, bivalves, crustaceans, ruminant meat, fish, eggs, and dairy provide high densities of bioavailable micronutrients per unit of mass and energy. For example, just 11 calories or seven grams of liver are needed to provide an average of one-third of the recommended intakes for women aged 15 to 49 y across all six priority micronutrients. In contrast, 667 calories and 499 grams of pulses are needed for the same priority micronutrient value. However, minimally processed pulses provide many other nutrients, protect against DR-NCDs, are one of the most affordable and sustainable healthy foods, and are underconsumed, so they should not be neglected (58, 59). Not all ASFs are equal, either. For example, more calories of chicken are needed to provide comparable priority micronutrient value to liver (>100× more calories) and pulses (1.6× more calories). Additionally, there are diverse ASFs besides liver that are highly nutritious but less common in higher-income countries, like other organ meats, small dried fish, insects (60, 61), and goat meat, among others.

Fig. 2.

Calories and grams needed to provide an average of one-third of recommended intakes of vitamin A, folate, vitamin B12, calcium, iron, and zinc for women aged 15 to 49 y. Each micronutrient’s contribution is capped at 100% of recommended intakes. Vit, vitamin. Modified from Beal and Ortenzi (62).

As shown in Fig. 1, infants and young children during the complementary feeding period require the highest iron density of any life stage. Their small stomachs make it challenging to meet their higher iron needs through food. The ideal food sources of iron in terms of mass are organ meats, seeds, bivalves, lean ruminant meat, and certain fish (Fig. 3), each providing at least one-third of the iron requirements from complementary foods in 50 grams or less. Nonetheless, parents’ concerns with choking on fish bones or other aquatic foods (63) or lower socio-economic status may contribute to the low consumption of varied types of seafood and organ meats among infants and young children (64–67). Low-calorie iron-rich foods like dark green leafy vegetables, which have high iron density per unit energy, are less optimal iron sources for young children due to their relatively low iron density per unit mass, requiring over 100 grams to provide a third of iron requirements (Fig. 3). However, dark green leafy vegetables are among the top sources of priority micronutrients, protect against DR-NCDs, and are affordable (58, 62, 68).

Fig. 3.

Calories and grams needed to provide one-third of recommended iron intakes from complementary foods for children aged 6 to 23 mo. Vit, vitamin. Modified from Ortenzi and Beal (69).

Global Patterns of Animal-source Food Consumption

While understanding the nutrient needs across the life cycle and what ASFs and plant-source foods are critical to filling those needs, the types of foods people can access and consume present a challenge in meeting those nutritional needs. As shown in Fig. 4, excluding unprocessed poultry meat, overall ASF consumption is highest in Central or Eastern Europe and Central Asia and lowest in South Asia and sub-Saharan Africa. Unprocessed red meat and processed meat consumption are both highest in Central or Eastern Europe and Central Asia and lowest in South Asia. Seafood consumption is highest in Southeast and East Asia and lowest in South Asia. Egg consumption is highest in Southeast and East Asia, Central or Eastern Europe, and Central Asia and lowest in South Asia and sub-Saharan Africa. Dairy consumption is highest in Central or Eastern Europe and Central Asia and high-income countries and lowest in sub-Saharan Africa and Southeast and East Asia. Interestingly, seafood consumption in Mozambique—one of the countries with the lowest overall ASF consumption—is higher than the global average. Additionally, unprocessed red meat consumption is lower in high-income countries, including the United States, than the global average.

Fig. 4.

Modeled estimates of per person daily dietary intake of animal-source foods, excluding unprocessed poultry meat. Data are from Miller et al. (70).

These global data, as presented, do not reflect differences within regions or subnationally in consumption of ASFs, which has been shown, especially at the country level among LMICs, to be driven by place, norms, education, access, and affordability (71). In many LMICs, ASFs are challenging to access because of the lack of infrastructure (e.g., cold chain storage, adequate roads, sanitary abattoirs, etc.) that could ensure their safe storage, delivery, and marketing (72, 73). Specifically, the relative prices of dairy products, eggs, and white meat are strongly associated with income levels. These types of ASFs are cheap in high-income countries but expensive in most LMICs, particularly in sub-Saharan Africa (16). The high price of ASFs is due to supply constraints, including the high perishability of products like milk and eggs, and poor productivity in the dairy and poultry sectors of low-income countries (16), as well as low minimum wages (74).

ASFs are, however, rich sources of nutrients and can benefit human growth and development (75). They are also crucial because of their high density and bioavailable protein, omega-3 fatty acids, and micronutrients, making them particularly important for young children with access to little diversity in their diets in LMICs. Small-scale livestock interventions have been shown to improve the affordability of ASFs in these settings (76–78), posing as one of a few promising interventions to improve access and consumption of ASFs among young children.

Implications and Future Directions

In this paper, we uncovered the biological nutritional vulnerabilities stemming from high micronutrient needs in certain phases of the life cycle. This analysis underscores the elevated micronutrient density needs of infants and young children, women of reproductive age, pregnant and lactating women, and older adults, particularly older women. We discussed the role of plant-source foods and ASFs in meeting nutritional needs at different life stages, highlighting foods and food groups with high nutrient density per gram or calorie.

While other papers in this series discuss issues of ASFs in their production, access, and sustainability, we put the vulnerable populations we highlighted at the center of our recommendations as this is the only way to ensure principles of equity ground our solutions (24). Therefore, food systems policies, interventions, and programming should prioritize pregnant and lactating women, young children, adolescent girls and women of reproductive age, and older adults, particularly those living in conflict and poverty and those who are marginalized (24). Since many people lack access to healthy diets due to various constraints and shocks to food systems, social protection mechanisms must be implemented for low-income populations. Governments need to provide assistance to ensure that populations can meet their nutritional needs and manage the risks and shocks they face (79, 80). The social protection mechanism may look different for each localized context, not just by way of who needs coverage concerning their vulnerability and marginalization, but packages of different policies (e.g., agricultural, food, trade, etc.) that impact those populations.

In contrast, many living in Central and Eastern Europe, Central Asia, high-income countries, Latin America and the Caribbean, the Middle East and North Africa, Southeast and East Asia, and high-consumers in countries of all incomes could afford to decrease their consumption of ASFs, particularly when they are not living through a critical stage of the life cycle that demands higher nutrient needs. However, any reductions in ASF consumption should be accompanied by efforts to replace them with nutrient-dense, plant-based foods like vegetables (especially dark leafy greens), legumes, and seeds, given that micronutrient deficiencies are ubiquitous across countries of all incomes (7). This could mean incentivizing high-income country households to move away from meat as the centerpiece at every meal and use meat more for flavoring and relish, including diverse plant-based protein-rich foods on the plate. Sustainability concerns can also be addressed through increased consumption of nutrient-dense ASFs with low environmental impacts, including mollusks, insects, and whole small fish (81). This behavior change can also be done through food environment choice architecture modifications or price disincentives that reflect the true cost of foods (82). For those living in lower-income countries and consuming too few nutrient-dense foods, more ASFs and promoting more nutrient-dense plant-based foods beyond just grains could benefit their nutritional status. To ensure that a diverse set of foods are available in markets, there need to be significant investments in improving and transforming food supply chain infrastructure using renewable energy market incentives while also increasing purchasing power and employing social protection mechanisms to safeguard the access of families in need.

Research demonstrates that iron, zinc, calcium, and vitamin B12 are critical nutrient gaps related to low ASF consumption, which require extra attention. ASFs and plant-based foods, particularly dark leafy green vegetables, seeds, and legumes, can help fill those gaps and should be promoted and affordable. More incentives for smallholders to produce horticultural foods and ASFs in the places where these commodities can be grown should be instilled by the private sector and governments.

While the evidence signals that ASFs are rich sources of nutrients commonly lacking globally, there are research and data gaps that should be addressed. As for research gaps, there is a need to understand how much ASF and which types are optimal for each population to provide adequate nutrition and minimize DR-NCD risk. Studies that model the health and sustainability of global diets need to account for the bioavailability of iron, zinc, and other nutrients, which are reduced among vegan, vegetarian, and flexitarian diets (51). Given the need to moderate ASFs to meet global sustainability targets (58) and parallel efforts to promote alternative ASFs, more research is needed to understand the health implications of replacing ASFs with alternatives, including plant-based, fungi-based, algae-based, insect-based, and cell-based proteins. Issues concerning the essential nutrient bioavailability of alternative ASFs are important to address (83), as are the vast differences in metabolomic profiles between ASFs and their alternatives (84).

Data gaps in global and nationally representative dietary and micronutrient status data for populations disaggregated by age and sex are substantial. The paucity of more detailed global food consumption patterns (85), particularly in LMICs (86, 87), presents a crucial limitation to the analyses presented here. Recent efforts to model dietary intakes contribute to filling some of the data gaps. Still, challenges remain in understanding differences in modeled results across databases (88) and their implications for meeting nutrient needs through food. In addition, within-country differences in the consumption of nutrient-dense foods, including ASFs, are often not captured, further obscuring intake deficits in subpopulations whose varying socioeconomic status, cultural practices, and preferences may augment nutritional vulnerability, especially of young children, adolescent girls, women of reproductive age, and the elderly (25, 87, 89). While adolescent boys and men are not particularly biologically vulnerable to micronutrient deficiencies, without data on their diets and micronutrient status, efforts to address inequities are hampered. Sociocultural and socioeconomic factors that influence ASF consumption are important to capture in different contexts if consumption patterns are to be understood. Some evidence shows that factors such as occupation, interpersonal relationships, land ownership, and perceptions of celebration or luxury foods influence ASF allocation within households (90). To be evidence-based and adaptive in our decision-making and policy approaches, data gaps on population-level micronutrient deficiencies and diets need to be filled (7, 24, 79).

Materials and Methods

Estimating Priority Micronutrient Density Needs by Life Stage and Sex.

This analysis focuses on six micronutrients of public health significance: iron, zinc, calcium, folate, vitamin A, and vitamin B12. These micronutrients were selected due to the availability of biomarkers indicating their population prevalence worldwide, their public health burden, and their critical role in supporting human growth and development at particular life stages (7, 62, 91, 92).

Population.

We used the 2021 global population from UN Population Statistics for ages 6 mo to 79 y (93). Infants 6 mo of age and younger are assumed to derive their nutrition from breast milk or formula and were thus not included in the study population. For infants aged 7 to 11 mo, 50% of the 0 y was used. The number of pregnant and lactating women was calculated based on the UN Population number of births per age of the woman. Pregnant women are assumed to be 75% of births (9 out of 12 mo). Lactating women are assumed to correspond to 50% of births (6 out of 12 mo).

Energy requirements.

Average requirements for energy from the European Food Safety Authority (EFSA) were used. No energy requirements are available for adults ages 80 and older. Energy requirements for 1 to 3-y-olds reflect physical activity levels (PAL) of 1.4 (low active), while for ages 4 and above, it reflects PAL of 1.6 (moderately active). Only PAL 1.4 is provided for ages 1 to 3. Energy for pregnant and lactating women was calculated as the average energy requirements for women ages 15 to 49 added to the additional pregnancy/lactation requirements. For pregnancy, energy requirements per trimester were averaged. Additional energy requirements for lactating women reflect lactation from 0 to 6 mo postpartum only.

Micronutrient recommendations.

For the six priority micronutrients, we used recommended intakes from two globally recognized sources: population reference intakes (PRI) from the EFSA for all micronutrients except for vitamin B12, which recommended dietary allowances (RDA) are from the Institute of Medicine were considered (94). The choice of the data source is in line with recent efforts to harmonize nutrient reference values based on the latest available review of the evidence (95). Adequate intakes (AI) are used for infants 7 to 11 mo for calcium, folate, and vitamin B12 in the absence of PRI or RDA. Recommended intakes for iron are lower in post- compared to premenopausal women. We assume women 50 and older to be postmenopausal, in line with the 15 to 49 women of reproductive age life stage designation (96).

Mean nutrient needs.

Mean global nutrient needs across all life stages were calculated based on the recommended nutrient intakes per energy intake needs by age and gender. Nutrient density needs (in nutrient amount per calorie) were weighted by the 2021 global population to arrive at the global population mean needs for males and females ages 7 mo through 79 y of age. Nutrient density needs of each life stage were compared to the global population mean needs across all life stages.

Micronutrient Density of Foods.

We plotted the priority micronutrient value of foods for women aged 15 to 49 y based on globally aggregated data (62). Values represent the calories or grams needed to provide an average of one-third of the recommended intakes of vitamin A, folate, vitamin B12, calcium, iron, and zinc. Each micronutrient’s contribution is capped at 100% of recommended intakes. For children 6 to 23 mo, we plotted the calories and grams needed to provide one-third of the recommended iron intake from complementary foods based on data from South and Southeast Asia (69).

Estimated Global Animal-source Food Intakes.

We plotted modeled estimates of daily ASF intakes, excluding unprocessed poultry meat, in grams per person per day from the 2018 Global Dietary Database (70).

Data, Materials, and Software Availability

All study data are included in the main text.