Proponents of raw foodism argue that cooking food increases the risk of some of the detrimental effects on food or health. They point out that during cooking of vegetables and fruit containing vitamin C, the vitamin elutes into the cooking water and becomes degraded through oxidation. Peeling vegetables can also substantially reduce the vitamin C content, especially in the case of potatoes where most vitamin C is in the skin. However, research has shown that in the specific case of carotenoids a greater proportion is absorbed from cooked vegetables than from raw vegetables.
Many people choose to forgo food from animal sources to varying degrees (e.g. flexitarianism, pescetarianism, vegetarianism, veganism) for health reasons, issues surrounding morality, or to reduce their personal impact on the environment, although some of the public assumptions about which diets have lower impacts are known to be incorrect. Raw foodism is another contemporary trend. These diets may require multivitamin supplements to meet ordinary nutritional needs.
Medical foods are foods that are specially formulated and intended for the dietary management of a disease that has distinctive nutritional needs that cannot be met by normal diet alone. In the United States they were defined in the Food and Drug Administration's 1988 Orphan Drug Act Amendments and are subject to the general food and safety labeling requirements of the Federal Food, Drug, and Cosmetic Act. In Europe the European Food Safety Authority established definitions for "foods for special medical purposes" (FSMPs) in 2015.
Live food is commonly used as feed for a variety of species of exotic pets and zoo animals, ranging from alligators to various snakes, frogs and lizards, but also including other, non-reptile, non-amphibian carnivores and omnivores (for instance, skunks, which are omnivorous mammals, can be technically be fed a limited amount of live food, though this is not known to be a common practice). Common live food ranges from crickets (used as an inexpensive form of feed for carnivorous and omnivorous reptiles such as bearded dragons and commonly available in pet stores for this reason), waxworms, mealworms and to a lesser extent cockroaches and locusts, to small birds and mammals such as mice or chickens.
Food marketing brings together the producer and the consumer. The marketing of even a single food product can be a complicated process involving many producers and companies. For example, fifty-six companies are involved in making one can of chicken noodle soup. These businesses include not only chicken and vegetable processors but also the companies that transport the ingredients and those who print labels and manufacture cans. The food marketing system is the largest direct and indirect non-government employer in the United States.
Some foods not from animal or plant sources include various edible fungi, especially mushrooms. Fungi and ambient bacteria are used in the preparation of fermented and pickled foods like leavened bread, alcoholic drinks, cheese, pickles, kombucha, and yogurt. Another example is blue-green algae such as Spirulina. Inorganic substances such as salt, baking soda and cream of tartar are used to preserve or chemically alter an ingredient.