One of the basic necessities for every form of live on our planet is food, without this most life will eventually perish. An average human needs around 2000 to 2500 kilo calories per day to stay fit and healthy, depending on physical activity. Although, there is enough food being produced in the world to provide all with the basic needs, not everyone receives enough food each day, where others consume too much, see figure below.
Our diet is mostly made up out of plants and animals. Plants give us vegetables, fruits bread, serials and many more. Animals give us mostly meat and other animal parts (e.g. liver, heart etc.). The cultivation and production of food require large amounts of land and effort. Currently around 40% of our total land is used for the cultivation of crops or the keeping of animals. For example in the figure below the percentage of lad use for agriculture is given for the U.S.