Food is any material consumed to supply nutrition to an organism. In the dietary world, food is generally of animal, plant or even fungi origin, and usually contains necessary nutrients, including proteins, carbohydrates, vitamins, or other minerals. Food is used to provide sustenance and energy to an individual or to maintain a community. Every living thing is capable of producing food, but only plants and animals can survive by consuming food from the environment. Most living things obtain nourishment from the food they consume, including animal and plant matter.

Plants generally obtain carbohydrates from the plants they consume and in the process of photosynthesis the sugars are transformed into starch, which is the main source of energy and sustenance for animals and most vertebrates. Animal food generally contains a combination of proteins, fat, vegetables, fruits and cereals and can provide an animal with both eating and energy. Milk, meat and bones are some animal-related products that are the primary sources of protein. Fruits and vegetables are the main sources of carbohydrates and are the main source of energy for animals and humans.

The major groups of foods that are generally categorized as foods that are central to human diet are carbohydrates, proteins, fat, vitamins and minerals, which together constitute the diet. The average intakes of the main food groups are from 70 g per day for a man of average height and a consumption of one or less g of each of the other food groups for a woman of the same height. Food is categorized in four groups: whole grain; brown or white rice, pasta and other pastas; fruits, vegetables, legumes and nuts; dairy products, with milk, cheese, yogurt and butter being the major categories. Fats constitute the largest proportion of fat in the diet and the proportion of saturated fat is greater in meats than in any other foods.