A functional food is a food given an additional function (often one related to health-promotion or disease prevention) by adding new ingredients or more of existing ingredients.[23] The term may also apply to traits purposely bred into existing edible plants, such as purple or gold potatoes having enriched anthocyanin or carotenoid contents, respectively.[24] Functional foods may be "designed to have physiological benefits and/or reduce the risk of chronic disease beyond basic nutritional functions, and may be similar in appearance to conventional food and consumed as part of a regular diet".[25]

Vitamins and minerals are required for normal metabolism but which the body cannot manufacture itself and which must therefore come from external sources. Vitamins come from several sources including fresh fruit and vegetables (Vitamin C), carrots, liver (Vitamin A), cereal bran, bread, liver (B vitamins), fish liver oil (Vitamin D) and fresh green vegetables (Vitamin K). Many minerals are also essential in small quantities including iron, calcium, magnesium, sodium chloride and sulfur; and in very small quantities copper, zinc and selenium. The micronutrients, minerals, and vitamins[16] in fruit and vegetables may be destroyed or eluted by cooking. Vitamin C is especially prone to oxidation during cooking and may be completely destroyed by protracted cooking.[17][not in citation given] The bioavailability of some vitamins such as thiamin, vitamin B6, niacin, folate, and carotenoids are increased with cooking by being freed from the food microstructure.[18] Blanching or steaming vegetables is a way of minimizing vitamin and mineral loss in cooking.
Anyone who eats a vegetarian diet knows that one of the most common questions asked is “Where do you get your protein?” But this gallery of recipes is your answer. We rounded up our favorite meat-free meals that also pack a serious punch of protein. With over 20 grams of protein per serving, these dishes are anything but rabbit food. Our hearty meals will keep you full and nourished by using vegetarian protein sources like tofu, eggs, lentils, tempeh, cheese, and beans. 
Anticarcinogens that may help prevent cancer can also be found in many food especially fruit and vegetables. Antioxidants are important groups of compounds that may help remove potentially harmful chemicals. It is however often difficult to identify the specific components in diet that serve to increase or decrease cancer risk since many food, such as beef steak and broccoli, contain low concentrations of both carcinogens and anticarcinogens.[144] There are many international certifications in cooking field, such as Monde Selection、A.A. Certification、iTQi. They use the high quality evaluation methods to make the food become more safe.
Dietary habits play a significant role in the health and mortality of all humans. Imbalances between the consumed fuels and expended energy results in either starvation or excessive reserves of adipose tissue, known as body fat.[149] Poor intake of various vitamins and minerals can lead to diseases that can have far-reaching effects on health. For instance, 30% of the world's population either has, or is at risk for developing, iodine deficiency.[150] It is estimated that at least 3 million children are blind due to vitamin A deficiency.[151] Vitamin C deficiency results in scurvy.[152] Calcium, Vitamin D, and phosphorus are inter-related; the consumption of each may affect the absorption of the others. Kwashiorkor and marasmus are childhood disorders caused by lack of dietary protein.[153]
Certain cultures highlight animal and vegetable foods in a raw state. Salads consisting of raw vegetables or fruits are common in many cuisines. Sashimi in Japanese cuisine consists of raw sliced fish or other meat, and sushi often incorporates raw fish or seafood. Steak tartare and salmon tartare are dishes made from diced or ground raw beef or salmon, mixed with various ingredients and served with baguettes, brioche, or frites.[96] In Italy, carpaccio is a dish of very thinly sliced raw beef, drizzled with a vinaigrette made with olive oil.[97] The health food movement known as raw foodism promotes a mostly vegan diet of raw fruits, vegetables, and grains prepared in various ways, including juicing, food dehydration, sprouting, and other methods of preparation that do not heat the food above 118 °F (47.8 °C).[98] An example of a raw meat dish is ceviche, a Latin American dish made with raw meat that is "cooked" from the highly acidic citric juice from lemons and limes along with other aromatics such as garlic.

In 2005, the population of the United States spent $496 billion on out-of-home dining. Expenditures by type of out-of-home dining were as follows: 40% in full-service restaurants, 37.2% in limited service restaurants (fast food), 6.6% in schools or colleges, 5.4% in bars and vending machines, 4.7% in hotels and motels, 4.0% in recreational places, and 2.2% in others, which includes military bases.[105][better source needed][relevant? – discuss]

Adulteration is a legal term meaning that a food product fails to meet the legal standards. One form of adulteration is an addition of another substance to a food item in order to increase the quantity of the food item in raw form or prepared form, which may result in the loss of actual quality of food item. These substances may be either available food items or non-food items. Among meat and meat products some of the items used to adulterate are water or ice, carcasses, or carcasses of animals other than the animal meant to be consumed.[13]