The global food supply system is facing serious new challenges from economic and related crises and climate change, which directly affect the nutritional well-being of the poor by reducing their access to nutritious food. To cope, vulnerable populations prioritize consumption of calorie-rich but nutrient-poor food. Consequently, dietary quality and eventually quantity decline, increasing micronutrient malnutrition (or hidden hunger) and exacerbating preexisting vulnerabilities that lead to poorer health, lower incomes, and reduced physical and intellectual capabilities. This article introduces the series of papers in this supplement, which explore the relationships between crises and their cumulative impacts among vulnerable populations, particularly through hidden hunger.