Food is any material consumed to supply nutritional support to an organism. In the human diet, food is generally of animal, plant or fungi origin, and usually includes essential nutrients, including proteins, carbohydrates, vitamins, or iron. The majority of food is water soluble, which means it is either digested in the small intestine by bacteria in the colon or passes through the bloodstream to reach the rest of the body in urine or feces. Some food is so soluble that it can be partially absorbed in the small intestine, and some, called super foods, is so complex that it needs to be digested and then metabolized inside the body. Food that is not metabolized is called fatty food, and most people prefer a diet rich in fat instead of food with complex carbohydrates. Fat is needed for energy production and the storage of carbohydrate energy, but is also a good source of fuel for exercise.
A balanced diet consists of the foods necessary for the maintenance of health, the development of the physical body, and the elimination of wastes. A well-balanced diet may include food from each of the five major food groups: carbohydrates, proteins, vegetables, fruits, and dairy products. Carbohydrates include breads, cereals, pasta, rice, potatoes, sugar, and fruit; proteins are meat, poultry, fish, eggs, beans, legumes, nuts, and vegetables; and fruits are fresh fruits, vegetables, legumes, nuts, and other legume based food. A healthy diet should contain some amounts of each of all the food groups.
Food processing methods can alter the nutrient content and therefore the value of the food. Processing methods, such as cooking, processing, freezing, juicing, milling, grinding, and fermenting, alter the chemical and physical properties of the food. Often, the composition of the processed food cannot be maintained as it was when it was raw, and the inherent chemical and physical properties are disturbed. Therefore, the nutritional values of these foods may be affected. Therefore, it is essential that the food we eat contains the correct proportion of macronutrients, including fibre, protein, carbohydrate, and fat.