Food is any substance eaten to provide nutritional support to an organism. In most human beings, food is of animal, plant or bacterial source, and generally consists of essential nutrients, including vitamins, proteins, fats, carbohydrates or minerals. The physiological processes involved in food digestion involve break down of food materials to the various forms needed by the body for normal functioning. There are three main categories of food: animal food, plant food and inorganic food.
Animal food refers to meat, fish and other seafood that is consumed on a daily basis. Plants, such as vegetables, fruits, nuts, seeds, and whole grains are consumed on a less regular basis. Animal-based foods contain mostly protein, whereas plant-based foods contain mostly fat, vitamins and minerals. Animal-based foods are rich in vitamins A, B, C, D, E and K; whereas plant-based foods are rich in vitamins A, C, D, E, and K; and usually contain only trace amounts of folic acid and riboflavin, iron and calcium. Animal-based foods are usually rich in fat and salt, whereas plant-based foods are rich in fiber and phytochemicals. Meat is also a good source of protein, as are eggs.
Vegetables, fruit, nuts, seeds, whole grains and legumes are rich in a variety of nutrients, including vitamins, minerals, calories and phytochemicals, and are usually eaten on a daily basis. Fruits and vegetables are an excellent source of nutrition, as they are rich in vitamins A, C, D, E and K; and are easy to digest and absorb. The minerals found in fruits and vegetables consist of chromium, iron, manganese, sodium, potassium, silicon, calcium, magnesium, thiamine, niacin and riboflavin. Legumes, beans and nuts are also good sources of vitamins A, C, D, E and K; and are easily digested.