A famous historical quote, “Let your food be your medicine,” specified by Hippocrates, is the fundamental basis of the development of functional food. Novel foods known as “functional foods” are created by combining ingredients at a safe and high concentration to have the desired effect, aiming to improve or prevent health problems. Dietary fiber, probiotics, vitamins, materials, and macronutrients are the potential ingredients responsible for the desired functionalities in functional foods. These bioactive substances are plentiful and diverse in cereals, vegetables, and beverages, including proteins, vitamins, minerals, fatty acids, antioxidants, phenolics, flavonoids, and primary and secondary metabolites. All of these ingredients are capable of encountering diseases, such as diabetes mellitus, aging, neurodegenerative disorders, kidney disorders, cardiovascular problems and hypertension, metabolic syndrome and cancers, oxidative stress and inflammations, and so on. This chapter’s primary goal is to discuss functional foods, their nutritional and functional worth, and the health advantages of cereals, vegetables, minerals, beverages, proteins, and vitamins.