better reflects what people eat. The evidence to date on the health effects of dietary patterns is consistent with the WHO and GBD findings, suggesting a focus on plant-based diets and lower level of food processing (FAO and WHO 2019) **.**

**While there is evidence of diets changing globally over time, there are no harmonized metrics monitoring diet quality or how diets are evolving** (Verger et al. 2023) **. Diets are assessed in a variety of ways, based on the population of interest and type of data available** . For example, breastfeeding practices are measured for infants and children 0-23 months of age. Measures distinguish those who are exclusively breastfed up to six months and continue to be breastfed while receiving complementary food up to 23 months from those who entirely stop breastfeeding at any time and receive instead breast-milk substitutes such as commercial infant formula and/or animal milk. For LMICs, the micronutrient adequacy of the diet is estimated using updated standardized methods for the assessment of minimum diet diversity (MDD) in children 6-23 months of age (WHO and UNICEF 2021) and minimum diet diversity in non-pregnant women of reproductive age (15-49 years, MDD-W) (FAO 2021). However, diet diversity is also assessed among other age groups (Arimond et al. 2021) and pregnant women (e.g. by the most recent Demographic Health Surveys). Since the consensus on standardized metrics for monitoring healthy diets is just emerging (Verger et al. 2023), current evidence focuses on dietary risk factors associated with negative nutrition and health outcomes, such as inadequate consumption of fruits, vegetables, legumes, whole grains, meat, dairy and fiber, or overconsumption of salt, trans-fatty acids, red meat, processed meat and sugarsweetened beverages.

# **_Outcomes of interest_**

**Second, the outcomes of interest are all forms of malnutrition and diet-related co-morbidities such as type II diabetes and hypertension** defined as including undernutrition (such as child wasting, child stunting, child/adult thinness or child/adult micronutrient deficiencies), overweight and obesity, and diet-related NCDs such as heart disease, stroke, diabetes and certain cancers (WHO 2023b). As overweight and obesity increase in poorer populations of LMICs, the coexistence of undernutrition (e.g. stunting) and overweight or obesity in the same individual, one form of the ‘double burden of malnutrition’, is also increasing (Popkin, Corvalan, and GrummerStrawn 2020). The Developmental Origins of Health and Disease (DOHAD) theory proposes a biological basis for why diets with inadequate energy and nutrient levels during early pre-conception and pregnancy predispose offspring to higher risks of obesity and associated NCDs in adulthood (Wells et al. 2020). Coexisting micronutrient deficiencies, estimated to affect over half of preschool-aged children and two-thirds of non-pregnant women of reproductive age (Stevens et al. 2022), contribute to a “triple burden” of malnutrition. Furthermore, co-morbidities associated with overweight and obesity, such as type II diabetes (T2DM) and hypertension are common (Agrawal and Agrawal 2016), including among children (Obita and Alkhatib 2022).

Malnutrition status based on anthropometric measures of weight and height are defined by age group. In children under five, we focus on stunting (height-for-age z-score <-2 SD); wasting (weight-for-height z-score <-2 SD); and overweight (weight-for-height z-score >2 SD) (de Onis 2006). In older children and adolescents, measures of thinness (BMI for age z-score <-2 SD) and obesity (BMI for age >+2 SD) are most relevant (Butte, Garza, and de Onis 2007). Similarly, in individuals 20+ years, BMI-based measures of thinness (BMI <18.5); overweight (BMI 25-29) and obesity (BMI 30+) are used to describe nutrition outcomes of concern (Abarca-Gómez et al. 2017). Micronutrient deficiencies commonly are defined using biochemical measures in children and adults, including, for example iron deficiency (inflammation-adjusted serum ferritin concentration), vitamin A deficiency (inflammation-adjusted serum retinol concentration) and anemia (hemoglobin concentration). Diet-related NCDs are defined using clinical measures, including diabetes (raised fasting blood glucose levels) and hypertension (raised blood pressure) as the two most critical metabolic risk factors for a range of diseases (World Cancer Research Fund International and The NCD Alliance 2014). We chose diabetes and hypertension as the diagnosis was linked to the highest metabolic risk factors associated with raised blood glucose and raised blood pressure aligned with the WHO STEPwise approach to NCD risk factor surveillance in LMICs (WHO, n.d.).

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