A challenge instigated by a group of friends with different diets and eating habits takes the viewers of Sustenance on a global journey in search of the dimensions of sustainability. Sustenance is a feature-length documentary about food's journey around the world and its consequences. It explores and debunks popular theories about food's sustainability and tries to shed light on the ethical aspect of food production relating to both human beings and the ecosystem. Sustenance's participants are renowned food activists, experts, authors, environmentalists, and farmers; figures such as Lierre Keith, Allan Savory, Joel Salatin, Nora Gedgaudas, and Derrick Jensen.