How Does Your Body Nutritional Needs Change As You Age

Food is any material consumed to supply nutriments for an organism. Food is generally of animal, plant or bacterial source, and has necessary nutrients, including proteins, carbohydrates, vitamins, or iron. A primary function of the body is to consume food and process it into energy or other materials useful to an organism, but in the digestive system the food is broken down into simpler substances that can be digested and absorbed into the body through the small intestine. The food that an animal consumes may be divided into two major categories: animal food and plant food. Animal food includes meat, milk, eggs, fish, poultry, and other processed forms of animal protein; plant food refers to fruits, vegetables, nuts, seeds and legumes (such as beans, peas, and corn); the majority of which are plant products with a few being animal foods.

Each type of food will supply a different number of nutrients to an individual, depending on what the food is and the physiological makeup of the person. For instance, plant food generally has more iron and other nutrients than animal food, as plants are more dense in these nutrients than animals. Meat provides much less total protein and iron than other animal foods, although meat is high in protein and iron.

Foods are categorized into three major groups according to their physiological characteristics. Fruits, vegetables, nuts, and grains are all part of the first group, whereas meats, dairy, roots, and other living things are part of the second group. Animal food is the largest source of food, supplying all the calories and nutrients needed by humans for general health and maintenance, as well as many other essential nutrients that cannot be obtained from plant food. In addition, animal food is the richest in dietary fiber.