Food is any material consumed to give basic nutritional support to the organisms. Generally speaking food is of plant, animal, or microbial origin, and normally contains necessary nutrients, including proteins, vitamins, carbohydrates, and minerals. A variety of diets are available for the general public to meet their needs for food. In a nutritionally dense diet, food provides all energy needs of an individual or family. Food sources are categorized into three main categories: animal foods, plant foods, and fungi or microorganisms.
Animal foods are those that derive their nourishment from animals, birds, mammals or insects. Fish and shellfish are an excellent source of protein, as are poultry, eggs and lentils. Meat and other processed or prepared meats, dairy products and processed milk are excellent animal foods. Meat used in the food industry comes from cattle, pork, goat, poultry and fish.
Plant foods are foods that derive their nutrient value from plants, which includes fruits, vegetables, and whole grains. Fruits, such as orange juice, prunes, melons, apples and most other fruit juices, are a rich source of antioxidants, vitamins and minerals, as well as fiber. Vegetables such as spinach, carrots, beets, beans and okra are high in carbohydrates but low in fat. Grains such as millet, sorghum, polenta and flax seeds are good sources of dietary fiber. Fungi and microorganisms such as yeast and mold, on the other hand, are food sources that are rich in nutrients but not nutrient-rich in calories.