Food is any material consumed in order to give nutrition to an organism. Food is generally of animal, plant or fungi origin, and usually contains vital nutrients, including proteins, carbohydrates, vitamins, or any combination thereof, which the body needs in order to function properly. It is the main source of energy for the body, regulates the functions of all organs and tissues, stores energy (such as that used during exercise), and is the major element involved in the building and maintenance of all cells. Food can be classified into three main categories: plant foods, animal foods, and fungi foods. Plants include all kinds of vegetables and fruits, grains, seeds, and roots; animals include milk, meat, eggs, fowl, and fish; and fungi include molds, yeasts,romyces, protozoa, salivary glands, and other microorganism that are not vegetable or animal origin.
The physiological makeup of humans is substantially different from that of other animals, and this has been the basis for the basis of the diet of some of the more ancient human cultures. Primitive people had to hunt and gather food, because the plants that they ate were not always available to them. In many cases, humans had to eat what their ancestors had already eaten before them. As people developed into complex beings, the need for food developed along with the ability to produce it. As food became more abundant, and human development progressed, so did the necessity for food.
There are two major ways that humans consume food: by cutting it up into smaller pieces and consuming the entire substance, or by eating the whole thing. In the process of cutting down food into smaller pieces, some of the nutrients that the food might contain are lost, because the small blades of the knife cannot break down the large substance into a digestible matter. In the process of eating the whole thing, the substance breaks down into more than its usual volume, so that most if not all of the nutrients remain. By understanding how nutrition relates to digestion, you can understand why you need to pay special attention to the foods that you ingest, and you can also understand why some types of food will be more appropriate for your body than others. By using the information that you have gained on this topic, you should be able to choose the foods that you consume based on how well the nutritional properties of them are represented in your body.