Cereals provide the largest single source of protein in the diet of most people in the world. However, cereals in general are not a good balanced food. They often lack sufficient proteins, and the proteins have an inherently unsatisfactory nutritional balance of amino acids such as lysine and tryptophan, which are essential for proper growth and health. A large proportion of people living in tropical and subtropical countries in Central and South America, Africa and Asia, exist on diets consisting largely of cereals and consequently suffer varying degrees of protein deficiency. Although some attempts have been made to alleviate this deficiency by the use of animal protein, leaf protein, fish meal and legume protein, the impact on the problem has been insignificant.
The protein content of wheat grown in the USA has declined by nearly one-third as a result of a decade of fossil-fuel-based farming which has reduced the soil's vitality. Food quality is reduced by intensive farming because of a combination of factors: artificial fertilizers, topsoil loss, loss of soil structure and organic matter, soil compaction by heavy machinery, and burning out soil organisms with chemicals.