Mars One: “The Living Unit is a Lander that has a unique, inflatable living section and an airlock used by the astronauts when leaving the sealed, habitable settlement. The Living Unit will be set in place by the Rovers and filled with breathable air by the Life Support Unit prior to the arrival of the astronauts. In addition, the Lander contains construction materials for the astronauts to construct rooms, floors and install electrical outlets. The Lander itself contains the 'wet areas', such as the shower and kitchen. The inflatable Living Unit will be built around existing technologies in use as Space Inflatables with such equipment as NASA's space suits and landing airbags on the three Mars rovers prior to Curiosity.”
Some food will be brought along, but the idea is for the colonists to eat the fresh food they produce on Mars. Also, bugs reproduce rapidly and can convert material that is inedible to humans into body mass, so small insect farms could produce a steady stream of food containing valuable fats and amino acids.