For people who are healthy, a healthy diet is not complicated and contains mostly fruits, vegetables, and whole grains, and includes little to no processed food and sweetened beverages. The requirements for a healthy diet can be met from a variety of plant-based and animal-based foods, although a non-animal source of vitamin B12 is needed for those following a vegan diet.[29] Various nutrition guides are published by medical and governmental institutions to educate individuals on what they should be eating to be healthy. Nutrition facts labels are also mandatory in some countries to allow consumers to choose between foods based on the components relevant to health.[30]

Between the extremes of optimal health and death from starvation or malnutrition, there is an array of disease states that can be caused or alleviated by changes in diet. Deficiencies, excesses, and imbalances in diet can produce negative impacts on health, which may lead to various health problems such as scurvy, obesity, or osteoporosis, diabetes, cardiovascular diseases as well as psychological and behavioral problems. The science of nutrition attempts to understand how and why specific dietary aspects influence health.
Various types of cook-tops are used as well. They carry the same variations of fuel types as the ovens mentioned above. Cook-tops are used to heat vessels placed on top of the heat source, such as a sauté pan, sauce pot, frying pan, or pressure cooker. These pieces of equipment can use either a moist or dry cooking method and include methods such as steaming, simmering, boiling, and poaching for moist methods, while the dry methods include sautéing, pan frying, and deep-frying.[93]
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]
Some experts have said that speculation has merely aggravated other factors, such as climate change, competition with bio-fuels and overall rising demand.[122] However, some such as Jayati Ghosh, professor of economics at Jawaharlal Nehru University in New Delhi, have pointed out that prices have increased irrespective of supply and demand issues: Ghosh points to world wheat prices, which doubled in the period from June to December 2010, despite there being no fall in global supply.[122]

Freezing food preserves it from the time it is prepared to the time it is eaten. Since early times, farmers, fishermen, and trappers have preserved grains and produce in unheated buildings during the winter season.[20] Freezing food slows down decomposition by turning residual moisture into ice, inhibiting the growth of most bacterial species. In the food commodity industry, there are two processes: mechanical and cryogenic (or flash freezing). The freezing kinetics is important to preserve the food quality and texture. Quicker freezing generates smaller ice crystals and maintains cellular structure. Cryogenic freezing is the quickest freezing technology available due to the ultra low liquid nitrogen temperature −196 °C (−320 °F).[21]
As previously discussed, the body is designed by natural selection to enjoy sweet and fattening foods for evolutionary diets, ideal for hunters and gatherers. Thus, sweet and fattening foods in nature are typically rare and are very pleasurable to eat. In modern times, with advanced technology, enjoyable foods are easily available to consumers. Unfortunately, this promotes obesity in adults and children alike.
There are very many methods of cooking, most of which have been known since antiquity. These include baking, roasting, frying, grilling, barbecuing, smoking, boiling, steaming and braising. A more recent innovation is microwaving. Various methods use differing levels of heat and moisture and vary in cooking time. The method chosen greatly affects the end result because some foods are more appropriate to some methods than others. Some major hot cooking techniques include:

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.


Also, the natural sugar in fruit does affect your carbohydrate intake — especially if you eat a lot of fruit. This may temporarily raise your blood sugar or certain blood fats. However, this effect is lessened if you are losing weight. If you have diabetes or any other health conditions or concerns, work with your doctor to adjust the Mayo Clinic Diet for your situation. For example, people with diabetes should aim for more vegetables than fruits, if possible. It's a good idea to snack on vegetables, rather than snacking only on fruit.
German research in 2003 showed significant benefits in reducing breast cancer risk when large amounts of raw vegetable matter are included in the diet. The authors attribute some of this effect to heat-labile phytonutrients.[27] Sulforaphane, a glucosinolate breakdown product, which may be found in vegetables such as broccoli, has been shown to be protective against prostate cancer, however, much of it is destroyed when the vegetable is boiled.[28][29]
A particular diet may be chosen to seek weight loss or weight gain. Changing a subject's dietary intake, or "going on a diet", can change the energy balance and increase or decrease the amount of fat stored by the body. Some foods are specifically recommended, or even altered, for conformity to the requirements of a particular diet. These diets are often recommended in conjunction with exercise. Specific weight loss programs can be harmful to health, while others may be beneficial and can thus be coined as healthy diets. The terms "healthy diet" and "diet for weight management" are often related, as the two promote healthy weight management. Having a healthy diet is a way to prevent health problems, and will provide the body with the right balance of vitamins, minerals, and other nutrients.[4]
Foods that spoil easily, such as meats, dairy, and seafood, must be prepared a certain way to avoid contaminating the people for whom they are prepared. As such, the rule of thumb is that cold foods (such as dairy products) should be kept cold and hot foods (such as soup) should be kept hot until storage. Cold meats, such as chicken, that are to be cooked should not be placed at room temperature for thawing, at the risk of dangerous bacterial growth, such as Salmonella or E. coli.[139]

Kosher foods are those that conform to the Jewish dietary regulations of kashrut (dietary law), primarily derived from Leviticus and Deuteronomy. Food that may be consumed according to halakha (law) is termed kosher (/ˈkoʊʃər/) in English, from the Ashkenazi pronunciation of the Hebrew term kashér (כָּשֵׁר), meaning "fit" (in this context, fit for consumption). Food that is not in accordance with law is called treif (/treɪf/; Yiddish: טרײף‎, derived from Hebrew: טְרֵפָה‎ trāfáh) meaning "torn."
In whole grain foods, the higher fiber content effectively displaces some of the starch component of the flour. Since certain fibers have no food energy, this results in a modest energy reduction. Another technique relies on the intentional addition of other reduced-food-energy ingredients, such as resistant starch or dietary fiber, to replace part of the flour and achieve a more significant energy reduction.
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