Background

Food consumption
But why is the focus on food and proteins? After water, food is the most basic human need. There are many different diets and what kinds of food are consumed where, strongly depends on geography, culture and income. A general trend can be described of food consumption patterns in relation to income (e.g. see Grigg, 1995). Diets of people with low income rely on staple foods: coarse cereals such as barley and millet, and roots and tubers such as tapioca. With a rise in income the initial response is to satisfy the demand for food, and the consumption of staples increases. Once the basic need has been satisfied, more expensive cereals like wheat and rice replace the coarse staples. With a further rise in income more luxurious foodstuffs such as fruits, vegetables, meats and sweets gradually replace part of the cereals. Finally a point of saturation is reached - there is after all only so much food you can eat - with a diet generally high in animal proteins, in sugars and in fats.

Proteins
The craving for animal food seems to be rather universal. During the last forty years, the supply of animal proteins has steadily increased from 7 kg to 10 kg per person globally (by comparison, animal protein supply in the European Union has reached the point of saturation at 20 to 27 kg!). During the same period, the total supply of animal protein production more than doubled from 25 billion kg to 60 billion kg due to the increased number of people.
The production of animal proteins is inefficient: 2 to 15 kg of plant foods are required to produce 1 kg of animal products. Presently, 40% of the global cereals harvest is used to feed the animals and satisfy the demand for their products. In theory, a reduction of animal proteins in high income diets would reduce such inefficient use of grains and spare the resources (land, water, nitrogen) required for their production and would thus be more sustainable.