Food is any material consumed to supply nutrients to an organism for growth, health or maintenance. Food is generally of animal, plant or fungi origin, and usually contains essential vitamins, including proteins, carbohydrates, fat, minerals or salts, and is consumed either to supply energy to the body or to act as a food source. The word food actually refers to anything that provides food and is not necessarily intended for human consumption. Humans consume food to satisfy their needs and to maintain health; whereas animals eat food for the purpose of increasing their reproductive capacity and/or to promote growth.
Foods are grouped into three main categories, including Plants, Animals and Fungi. Plants are classified as per Vegetable family, including beans, spinach, cabbage, tomatoes, squash, cabbages, carrots, corn, peas, herbs, potatoes, rice, and so on. Animals include fish, animals such as pigs, cattle, poultry, bovines, ham, ducks, mice, frogs, and so on. Fungi include yeast, mold, mushrooms, yeasts (Candida albicans), romances, salivarius, staphylococcus, candida, bacteria, yeasts (Proteobacteria sp. nov., bakersley tongue, Lactobacillus acidophilus, L. bulgaricus, Saccharomyces chevalieri, S. cerevisiae, Enterocarpus eximius), and sometimes manure which are classified under Fungi.
Under the classification of foods, there are several subcategories, including nutritional foods, edible substances, ready-to-eat foods, dietary supplements, frozen foods, processed foods and food additives. The nutrient content of different foods can be determined by scientific method such as analysis of whole grains, fresh fruits, vegetables, meats, and dairy products; or by using common method such as weighing. Commonly, nutrient values of most of the foods are provided on the label along with details about the amount of each nutrient present in edible substances. However, not all nutrients are included in the foods because some nutrients are naturally found in some foods, whereas some are required by man in food. Moreover, some nutrients are totally absent in the edible substances.