A raw food diet consists of raw fruits, vegetables, and grains. Although some warming is allowed, no foods can be heated above 115ºF (46ºC). Above this temperature, the natural enzymes in foods may be destroyed. Raw food advocates contend that these enzymes improve digestion and fight many chronic diseases. However, the enzyme concerns are unfounded. The human body creates and uses a variety of enzymes, and does not rely on those found in foods. During normal digestion, stomach acid breaks down enzymes in food anyway, making them useless. Therefore, you do not need to avoid cooking in order to preserve enzymes.
This emphasis on fruits, vegetables, and grains is in line with most nutrition recommendations. These foods are full of vitamins, minerals, fiber, and phytochemicals, while being low in calories, fat, and sodium. However, the severe limitations of this diet make it difficult to follow and create a risk for malnutrition.
Protein is a concern. Nuts and seeds provide protein and therefore must be eaten in great quantities to fulfill protein needs. Vitamin B12, which is only found in animal products, must be taken in supplement form. The low calorie content of the foods in a raw food diet make it necessary to eat a large quantity of food each day to meet basic calorie needs.
Raw food advocates believe that cooking not only destroys enzymes, but also makes food toxic. To support this belief, some raw food proponents cite the National Academies of Science 1982 report, Diet, Nutrition, and Cancer, which names acrylamide and heterocyclic amines (HCAs) as possible carcinogens. These chemicals are formed in foods during cooking. However, neither the American Cancer Society (ACS) nor the National Cancer Institute (NCI) goes so far as to recommend a raw food diet to reduce the risk of cancer from these chemicals. Instead, they stress that following a healthful diet—one rich in fruits, vegetables, and whole grains, both raw and cooked—is still the best known way to reduce cancer risk.
The foods with the highest levels of acrylamide are those that should be limited in a healthful diet anyway, such as potato chips and French fries. Experts see no need to avoid cooked potatoes entirely. Likewise, HCAs, which are formed when meat is cooked at above 300°F (149ºC) or above, may increase cancer risk. However, HCAs can be reduced through minor shifts in cooking methods, rather than significant dietary changes. For example, varying cooking methods; microwaving meat before frying, broiling, or barbecuing; and not making gravy from meat drippings.
While cooking decreases the levels of certain vitamins, it also increases the body’s absorption of carotenoids like beta-carotene and lycopene, both of which have beneficial properties. It is best to vary your diet—both in foods and in means of preparation.
Another benefit to cooking is that it kills bacteria. Food safety is an issue for all foods, not just meats and eggs. People following a raw food diet must take extra care in washing or peeling their foods before eating, as many staples of the raw food diet have been linked to food borne-illness. These include cantaloupe, sprouts, raspberries, green onions, and lettuce.
More than just a dietary habit, the raw food way of eating is part of a greater life philosophy. Many people who choose to follow this highly restrictive diet are striving to be closer to nature. The raw foods diet continues to be associated with a variety of social, spiritual, environmental, and psychological ideologies.
Raw foods are certainly healthful, there’s no disagreement about that. However, there is no evidence that consuming only raw foods—as opposed to a diet of both raw and cooked foods—prevents sickness and enhances mental acuity.
According to the US Department of Agriculture's dietary guidelines, each food provides a wide array of nutrients, so it is important to include all food groups in your daily diet.
Choose My Plate—US Department of Agriculture
Eat Right—Academy of Nutrition and Dietetics
Dietitians of Canada
Acrylamide in food and cancer risk. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/factsheet/risk/acrylamide-in-food. Updated July 29, 2008. Accessed January 27, 2016.
Carotenoids. Linus Pauling Institute website. Available at: http://lpi.oregonstate.edu/infocenter/phytochemicals/carotenoids/. Accessed January 27, 2016.
Chemicals in meat cooked at high temperatures and cancer risk. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/factsheet/Risk/heterocyclic-amines. Updated October 19, 2015. Accessed January 27, 2016.
Commission on Life Sciences. Diet, Nutrition, and Cancer [e-book]. The National Academies Press; 1982. Available at: http://books.nap.edu/books/0309032806/html/index.html. Accessed January 27, 2016.
Dietary guidelines for Americans 2005. Health.gov—US Department of Health and Human Services website. Available at: http://www.health.gov/dietaryguidelines/dga2005/document/html/chapter2.htm. Updated July 9, 2008. Accessed January 27, 2016.
Last reviewed January 2016 by Maria Adams, MS, MPH, RD