FAO, UNICEF & WHO | July 2024
Background
Healthy diets are essential for good nutrition and health. They help protect against all forms of malnutrition and many noncommunicable diseases (NCDs), such as heart disease, diabetes mellitus, and diet-related cancers (1–7). Access to a healthy diet is a fundamental human right (8).
Unhealthy diets are responsible for the highest burden of morbidity and mortality globally when considering all known risk factors. Many countries, particularly low- and middle-income ones, face nutrition and health issues caused by the coexistence of undernutrition, micronutrient deficiencies, and overweight and obesity. In 2017, one in five deaths globally—equivalent to 11 million deaths—was associated with poor diets and diet-related chronic diseases (9, 10). According to WHO estimates, the total annual number of deaths attributable to NCDs will increase from 36 million in 2008 to 55 million by 2030 if effective preventive measures are not taken (3).
In addition to affecting human health, dietary choices have significant implications for planetary health, as consumer demand is a major driver of food system trends that are, from a historical perspective, resource-depleting, inefficient, and contribute significantly to greenhouse gas emissions (7).
It is vital for countries to monitor their populations’ diets to inform actions towards improving the health of both people and the planet. The healthiness of diets must be tracked in global frameworks, such as the Sustainable Development Goals (SDGs), to help monitor how the world’s population is faring. Currently, few countries regularly assess diets, and there are no dietary indicators in global monitoring frameworks.
Recognising the importance of diets for health and the lack of consensus on how to measure and monitor healthy diets at scale, FAO, UNICEF, and WHO have joined forces to chart a way forward via the Healthy Diets Monitoring Initiative (HDMI) (11–15). The joint mission of HDMI is “to enable national and global decision-makers and stakeholders to monitor and achieve healthy diets for people and the planet”. See Annex 1 for more information on HDMI.
Given the broad scope of the mission statement, HDMI aims first to establish guidance for measuring healthy diets for public health. The current guidance document focuses on healthy diets for healthy people. This version provides an overview of the range of purposes for measuring the healthiness of diets and offers examples of the dietary assessment methods, types of dietary intake data, surveys, and metrics currently available to monitor healthy diets. A subsequent version will offer more detailed recommendations regarding the selection and operationalisation of metrics for healthy diet monitoring for healthy people.
In a later phase, HDMI intends to issue guidance on how to monitor healthy diets for both public and planetary health (i.e., including environmental sustainability considerations).
1.1 Objectives
The objectives of this guidance document are to provide an overview of:
- the purposes for which dietary intake data can be used;
- dietary assessment methods, types of dietary intake data, and surveys to collect data on the healthiness of diets;
- currently available healthy diet metrics and the core properties of healthy diets captured by them, according to the current body of evidence; and
- choices regarding dietary assessment methods and metrics for healthy diet monitoring.
1.2 Target audience
The target audience of this guidance document comprises individuals involved in using and interpreting dietary metrics. More specifically, the document is intended for:
- National governments:
- National statistics offices (reporting to governments on Sustainable Development Goals and World Health Assembly nutrition targets); and
- Ministries of health and agriculture.
- International and national organisations with an interest in diets and nutrition;
- Researchers and academia;
- Public health nutritionists and registered dietitians;
- Technical advisors on nutrition or dietary intake for policymakers; and
- Survey designers, managers, and implementers.
1.3 Approach for content development
The Core Group of the Healthy Diets Monitoring Initiative (HDMI) conceptualised and led the production of this document. It was prepared by a working group of experts who undertook its development, writing, and revision. Detailed information on the purposes of measuring healthy diets, types of dietary intake data, surveys for dietary data collection, dietary assessment methods, metric characteristics, and recommendations was derived from previous HDMI technical expert consultation reports and other publications.
Draft versions of the document were reviewed by all members of the Core Group. The final draft was also reviewed by subject-matter experts.
1.4 The properties of a healthy diet
The exact composition of a healthy diet will vary depending on age, sex, physiological status, lifestyle, degree of physical activity, cultural context, availability and affordability of local foods, and dietary customs, among other factors. However, the fundamental properties¹ of a healthy diet remain the same (16).
Based on a thorough review of the evidence, the HDMI (13,15) identified the following four properties that best reflect healthy diets for monitoring purposes:
- Nutrient adequacy: Sufficient quantity and quality of nutrient (micronutrient, macronutrient, and energy) intake to meet requirements, without excess.
- Macronutrient balance: A balance of energy-yielding macronutrients: carbohydrates, proteins, and fats.
- Diversity: Diets composed of a diverse range of foods from distinct healthy food groups. Dietary diversity between and within food groups increases the probability of meeting nutrient requirements.
- Moderation: Limited intake of foods and nutrients associated with NCD risks when consumed in excess (e.g., processed meat, sugar-sweetened beverages, salt, trans fats).
Monitoring these priority properties provides information on the healthiness of diets relevant to all forms of malnutrition: stunting, wasting, and underweight; micronutrient deficiencies; overweight, obesity, and other diet-related NCDs.
By expert consensus (13,15), two additional properties of healthy diets—food safety and nutrient density—were considered² but not selected as priorities for this document, as they are typically properties of foods rather than diets.
- Food safety: It is essential to ensure that food is safe for human consumption—that is, free from microbial pathogens, food-borne macroparasites, toxins, harmful residues, and chemical contaminants. However, it is challenging to assess dietary exposure to these hazards alongside the healthiness of diets, as such assessments require detailed, multi-day quantitative dietary data and data on microorganism levels, as well as chemical contaminant and residue levels in foods. Therefore, it is recommended to measure food safety using separate metrics that assess adequate levels of protection, acceptable exposure levels, or conformity with international food standards (17).
- Nutrient density: Nutrient density is a property of individual foods. Although nutrient density can be measured across a composite diet, the process is complex. Moreover, higher nutrient density is not always desirable (e.g., in the case of sugar, salt, or trans fats). Finally, while nutrient adequacy and nutrient density are distinct properties, they are closely related.
Download here the document “Guidance for monitoring healthy diets globally” in English
