# **1 Introduction**

Despite recent economic growth, increased health spending and improved coverage of key health interventions, the Philippines continues to struggle with persistently high child undernutrition. In nationally representative 2015 survey data, nearly 1 in 3 children under age 5 were stunted, a principal marker of undernutrition, and that figure was essentially unchanged from a decade previous. The World Bank’s Systematic Country Diagnostic highlights addressing the high level of undernutrition as a principal policy for the country. The government’s core planning document, the Philippine Development Plan, also recognizes the undernutrition challenge, and the government’s nutrition strategy, the Philippine Plan of Action for Nutrition, sets out an ambitious target of reducing stunting to 20 percent by 2022.<sup>1</sup> Policy attention to the issue is motivated by a large body of international research which shows that undernutrition in utero and early childhood has severe consequences. Childhood undernutrition is associated with increased risks of morbidity, mortality and cognitive deficits.<sup>2</sup> Longitudinal studies show links between childhood undernutrition and reduced schooling, learning outcomes, and economic productivity as an adult. One of these studies is the Cebu Longitudinal Health and Nutrition Study, which has tracked children born in the Philippines in the early 1980s. Children in the Cebu study who were stunted between birth and age 2 were found to have on average lower cognitive test scores at the ages of 8 and 11 years, delayed enrollment in school, higher absenteeism and repetition of grades, and a lower likelihood of holding a formal job in early adulthood.<sup>3</sup> Recent studies suggest that the total costs of childhood undernutrition in the Philippines is in the range of 1.5 to 3 percent of GDP per year.<sup>4,5</sup> There is growing evidence that cognitive, motor and socio-emotional deficits in early childhood, as well as schooling and learning outcomes later in life, are mediated through the brain’s architecture as it develops in an environment cut off from adequate nutrition, stimulation and care. The vast majority of neural development occurs between conception and infancy and the neural circuits that underpin key functions such as seeing and hearing, speech production and higher cognitive ability are established before the age of two.<sup>6</sup> Key processes such as the creation of neurons, the growth of axons and dendrites, synapse formation and pruning as well as myelination are dependent on key micronutrients.<sup>7</sup> New studies that use neuroimaging technologies to measure brain size and structure show alarming differences in brain architecture associated with chronic malnutrition and sensory deprivation.<sup>8</sup> While the Philippines has an excellent survey program that routinely monitors the nutritional status of children, there is limited published empirical evidence on the size, direction, interdependence and relative importance of stunting’s risk factors and interventions. The objective of this paper is to help fill that knowledge gap by conducting a systematic analysis of potential drivers of stunting. The paper begins with a discussion of the data used for the analysis, and then reviews the broad patterns of stunting in the Philippines and across countries. It next describes a conceptual framework for understanding undernutrition and presents the analysis and discussion.

# **2 Data**

The analysis in this report relies on the nationally representative 2015 National Nutrition Survey (NNS) conducted by the Department of Science and Technology’s Food and Nutrition Research Institute (DOST-FNRI). The 2015 NNS is an ‘updating’ survey, meaning that it was implemented in the years intervening the more comprehensive NNS surveys which are conducted every 5 years. The 2015 NNS 2