in urban areas. In all LMICs, other than in South Asia and Sub-Saharan Africa, rural overweight and obesity is growing faster than in urban areas, albeit originally from lower levels (Popkin, Corvaland and GrummerStrawn 2020). These different patterns have implications for agrifood and health policies.

# 3. Metrics for Healthy/Unhealthy Diets (Diet Quality)

Table 2 summarizes information on some commonly used dietary metrics available at different life-cycle stages, discussed in this section. Further details on sources, availability and methods of measurement are given in Appendix Tables 1, 2 and 3.

The growing burden of overweight and obesity, as well as NCDs, has required the development of novel healthy diet metrics to complement the more well-established metrics for energy sufficiency and nutrient adequacy of the diet (Table 2). The focus of the measures of (in)sufficiency and (in)adequacy has primarily been in children under 5 and in women of reproductive age (15-49), perhaps because these are the periods of greatest vulnerability to malnutrition and greatest probability of adverse outcomes. However, the outcomes of unhealthy diets affect all age groups, and new efforts to collect these data therefore also include adolescents (a period where eating habits may be established and maintained into adulthood) and adult men (who are also at risk of diet-related NCDs). In LMICs there has been to date less attention to older adults, while high-income countries with larger proportions of this age-group are already collecting data. There are very few data on younger school-age children (ages 5 through 12).

Detailed definitions and sources for diet variables are described in the Appendix Tables 1, 2 and 3, (corresponding to the lifecycle stages distinguished in Table 2) along with information on the number of countries/LMICs for which data are currently available. Since our focus is global, we have not included metrics specific to individual countries or regions. Data on metrics of nutritional and health status are well established and not reviewed here; UNICEF and WHO maintain global databases in this area (see Appendix Tables 4 and 5). Schooling outcomes and standardized test outcomes are available from UNESCO and key ones are included in the World Bank World Development Indicators database.

To help assess **energy sufficiency** , data on per capita food supply have been collated regularly at national level by FAO (and give some indication as to whether availability meets nutrient requirements). Measures compare food available and distributed and what is needed, according to the composition of the population by age, gender and physical activity levels. The Prevalence of Undernourishment (PoU, one of the suite of food security measures maintained by FAO) provides an estimate on how many people lack enough dietary energy for a healthy and active life. The prevalence of moderate or severe food insecurity based on the Food Insecurity Experience Scale (FIES, also maintained by FAO) provides an estimate on how many people do not have access to nutritious and sufficient food due lack of money or other resources. Energy sufficiency can also be assessed at the individual-level using quantitative dietary recall data.

To assess **nutrient adequacy** , quantitative data from dietary recall is considered to be the preferred source. However, given the difficulties in maintaining nationally-representative, up-to-date, quantitative data, metrics currently in widespread use employ recall to measure whether or not individuals consumed food from each of various food groups. One widespread summary population-level dietary indicator is that of **minimum diet diversity (MDD)** ; however, this has been developed only for young children and women. For children 6-23 months of age, MDD is defined as consumption of at least five out of eight food groups including breastmilk in the preceding 24 hours (WHO and UNICEF, 2021). For non-pregnant women of reproductive age (15-49 years), MDD-W is defined as consumption of at least five out of 10 food groups over the last 24 hours (FAO 2021). MDD-W has been validated as a proxy indicator for a minimally 5