Preparing food without electricity or gas is unthinkable in our industrialized countries, but it is daily routine in other parts of the world. Eating only uncooked food is not recommended for the human body, because some biomaterials are only eatable when boiled - like soy, beans, chick peas or lentils. These legumes are an important source of protein for people with limited access to animal products such as milk or meat. However, they contain lectines, which - when eaten raw - hinder the oxygen transport in the blood. In order to make these components harmless, they need to be cooked with heat.
Cooking on open fire is environmentally unfriendly, but it is inevitable as long as other means of energy are not available. In many developing countries wood is the only available source of energy for cooking. This can accelerate deforestation and be harmful to nature and people in general. Therefore, more sustainable means for cooking food are required in face of rapidly growing populations in many undeveloped regions of world.