Introduction Progress in reducing global levels of undernourishment has slowed considerably over the last decade, with estimates from the Food and Agriculture Organization (FAO) showing that worldwide 925 million people are still categorised as being chronically undernourished (FAO 2014). The prevalence of undernourishment globally is unacceptably high and accounts for 11.3 per cent of the population worldwide, with the developing world bearing much of the burden. There are also wide regional disparities, with countries in sub-Saharan Africa and South Asia making the slowest progress in achieving food and nutrition security. The FAO has recently estimated that the global cost of undernourishment, including inadequate overall calorie intakes and micronutrient defi ciencies, is 2-3 per cent of global GDP, equivalent to US$1.4-2.1 trillion per year (FAO 2013: ix). Understanding the nature of food and nutrition security in low-income settings is therefore critical in ensuring the sustainability of economic growth.