The increase of the Western-type diet and life-style, with high content of highly processed fats, salt and sugar, as well as sedentary life, is directly linked to an increasing incidence of chronic diseases such as diabetes and obesity, cancer, cardiovascular diseases or stroke, and inflammatory-related diseases, which are a great challenge in global health and are usually associated with negative effects of globalization: rapid urbanization, diet and increased sedentary life worldwide. This has brought new interest and increased research into plant-based diets. In this context, the implementation in the diet of legumes, cereals and pseudo-cereals, due to their nutraceutical properties, which is interesting as well as advisable. These foods, in addition of having a high nutritional value themselves, have synergistic properties as part of a balanced diet. For example, most legumes are rich in lysine which is scarce in cereals, and these are rich in sulphur amino acids, such as methionine, while these amino acids are scarce in legumes and are of great importance for the central nervous system development. These foods or part of a food, due to their qualities, and that they provide health benefits can be classified as nutraceuticals. In addition, due to their health benefits beyond nutritional properties, can be classified as functional foods, promoting prevention and treatment for the above mentioned diseases, among others. This double function is due mainly to the proteins and the presence of various secondary metabolites and bioactive compounds in these foods of plant (grain and seed) origin. Last discovered knowledge and research features will be described in the present book chapter.