When violence or natural disaster strikes vulnerable communities, good data on the hunger that often results can be hard to come by. For aid workers, knowing where food is scarce and how families are coping is crucial to alleviate suffering. M.J. talks to Jean-Martin Bauer, founder of the World Food Programme’s mobile Vulnerability Analysis and Mapping (mVAM) unit, about how mobile phones in the most remote and dangerous corners of our world are changing how we understand and fight hunger.