'Hungry Planet: What the World Eats' When you look at these pictures think about this: How will the excreta production of each family differ? How much fertiliser and water was required to make this food? Each chapter of their book features a portrait of a family, photographed alongside a week's worth of groceries. There's also a detailed list of all the food and the total cost.

The Aboubakar family of Darfur province, Sudan, in front of their tent in the Breidjing Refugee Camp, in eastern Chad, with a week's worth of food.

The Dong family in the living room of their one-bedroom apartment in Beijing, with a week's worth of food.

The Melander family -- Jörg, 45, and Susanne, 43, with sons Kjell, 10, and Finn, in the dining room of their home in Bargteheide, Germany, with a week's worth of food.

The Revis family in the kitchen of their home in suburban Raleigh, N.C., with a week's worth of food.