Whole foods are foods that have not been processed or refined. In most cases, they do not contain added sugar, fat, or salt. Examples of whole foods are whole, unpolished grains (grains containing the bran, endosperm, and germ of the original grain); nonhomogenized dairy products; unprocessed meat, poultry, and fish; and fruits, nuts and seeds, legumes, and vegetables. “Whole foods” should not be confused with “organic” foods, which are foods produced without the use of pesticides, fertilizers, hormones, antibiotics, other chemicals, or genetically modified seeds. Whole foods are not necessarily organic in origin, and organic foods can include processed foods.
Processed foods include all food products that have been altered in some way to either turn them into food, extend their shelf life, or prepare them for human or animal consumption. Processed foods can include foods prepared at home as well as in commercial food processing plants. Cat or dog foods and feed mixtures for farm animals are considered processed foods, as are Meals Ready-to-Eat (MREs) for combat troops and specialized foods prepared for mountain climbers, explorers, astronauts, and others working or traveling in environments where cooking would be difficult or impossible.
Convenience foods are a specific category of processed foods, known as tertiary processed foods. They require little preparation prior to eating and are typically packaged in single-serving portions. Convenience foods may include hot ready-to-eat dishes, shelf-stable products intended to be eaten at room temperature, or refrigerated or frozen products that require only heating before consumption. Candy, packaged baked goods, processed meats and cheeses, pasta dishes, TV dinners, frozen pizzas, single-serving portions of applesauce, pudding, fruit juices, soups, flavored milk, and some types of fast food are all examples of convenience foods.
Foods are processed for many different reasons:
Food safety is an important consideration for both whole and processed foods. It is of worldwide concern due to the increased globalization of food production and processing as well as the rise in international travel and tourism. People in the food industry use the acronym FAT TOM to remember the six conditions required for the growth of foodborne disease organisms: Food, Acidity, Time, Temperature, Oxygen, and Moisture. Monitoring these conditions is essential to food safety.
The move toward international standards in safety during food processing began in the 1960s when the National Aeronautics and Space Administration (NASA) asked the Pillsbury Company to invent and manufacture processed foods for space flights. To ensure the safety of the specialized foods required, the company instituted a preventive approach known as Hazard Analysis and Critical Control Points (HACCP). The U.S. Department of Agriculture (USDA) and the Food and Drug Administration (FDA) have made HACCP programs mandatory for meat, seafood, and juice processors, as well as retail or food service companies, while they are voluntary for other food industries.
In an HACCP program, food processors look for food safety hazards, defined as any biological, chemical, or physical property that would make a food unfit for human consumption. They then identify critical control points, which are points during the processing at which a food safety hazard can be prevented, eliminated, or reduced to an acceptable level. Other steps in an HACCP program include establishing critical limits for each control point; setting up a monitoring system; establishing corrective actions to be taken when critical limits are not met; setting up recordkeeping procedures; and verifying from time to time that the HACCP system is working as intended. The HACCP system is now used by a number of developed countries worldwide and has been extended to the manufacture of pharmaceuticals and cosmetics as well as processed foods.
The origins of food processing go back to human prehistory, as early humans are known to have cooked meat and dried it to preserve it. With the development of agriculture, various methods of crushing or milling whole grains to remove the husks and produce flour were created. Such cooking methods as boiling, baking, steaming, poaching, frying, and grilling, as well as fermentation and pickling, were known to the ancient Egyptians, Chinese, Greeks, Romans, and Native Americans. Prior to the invention of modern canning methods, salting and smoking were the major methods of food preservation for ancient and medieval soldiers and sailors.
Modern canning developed in response to military demands. It grew out of the work of Nicolas Appert (1749–1841), a French confectioner who won a prize offered by Napoleon in 1800 for anyone who could devise a safe and effective method of preserving food for an army on the march. Appert won the prize in 1810 after some years of experimentation. Appert's method involved placing foods in wide-mouthed glass jars, leaving some air space at the top, sealing the jars firmly with a cork, and dunking the jars in boiling water and boiling them for as much time as Appert thought appropriate for cooking the contents thoroughly. Appert's invention was followed the next year by Peter Durand, a British merchant who used tinned cans instead of glass jars to preserve food. Durand was granted a patent by King George III.
The pasteurization of milk was discovered by microbiologist Louis Pasteur (1822–1895) in 1862. In the twentieth century, food processing grew as an industry, and new techniques developed in response to the needs of troops in World Wars I and II, the space race, and the rising standards of living in the developed countries after 1945. Such advances as freeze drying, juice concentrates, and the use of artificial flavors and preservatives were all twentieth-century inventions, as was the introduction of TV dinners, convenience foods, and fast foods.
There are a number of different methods of food processing:
In addition to the various methods of food preparation, food processing also includes the packaging of foods as well as the application of edible coatings to fresh fruits and vegetables.
Currently, there is no recommended intake of whole foods versus processed foods. An increasing proportion of the world's foods are processed rather than being served as whole foods. A study published in 2009 reported that highly processed foods made up 50%–90% of the nutrients consumed in Europe, depending on the specific country. Another study of Inuit living near the Arctic Circle reported in 2009 that whole foods accounted for less than 40% of tribal members' diets, with the proportion of store-bought processed foods steadily increasing.
Reasons given for the growing worldwide shift toward processed foods include the general perceived safety of processed foods, the speed of modern methods of food transportation, and greater awareness of and desire for the variety of foods available around the world. This awareness in turn is the result of such communications media as television and the Internet, increased tourism, and increased population mobility.
The USDA's Dietary Guidelines for Americans 2010 states that people should lower the number of calories they take in from solid fats and added sugars, as well as foods containing refined grains, and especially any refined-grain products containing solid fats, added sugars, and excess sodium (salt). Most Americans two years and older eat a diet high in sodium, consuming approximately 3,400 mg each, in comparison to the 2,400 mg recommendation. Most of the sodium in American diets comes from processed foods where salt has been added. The USDA recommends eating more fresh foods and fewer processed foods to help limit sodium intake. The guidelines advise that half of a person's daily intake of grains should be whole grains—for a person consuming a 2,000 calorie diet, this would be no more than three one-ounce equivalents of processed grains per day (one ounce being about 1/3 cup of pasta or one slice of bread).
Solid fats and added sugars, mostly from processed foods, contribute to nearly 800 calories, or 35% of total calories per day for the average person in the United States. The USDA guidelines allow for about 5%–15% of total calories to come from added fats and sugars, or 32 grams in a 2,000 calorie diet. The majority of sugars consumed in “typical” Western diets are sugars added to foods during processing, accounting for 16% of a person's total caloric intake. These added sugars are used in processed foods to sweeten the flavor of foods and beverages and improve their palatability (taste). They also assist in preservation purposes and to provide viscosity, texture, body, and browning capacity to foods that have been processed. In general, the main intake of sugar in the United States is not from whole foods such as fresh fruit but instead comes from highly processed foods such as soda, energy drinks, and sports drinks (36% of added sugar intake); grain-based desserts (13%); sugar-sweetened fruit drinks (10%); dairy-based desserts (6%); and candy (6%).
According to the USDA, 19% of the total calories in American diets comes from solid (saturated) fats, which contribute few essential nutrients and no dietary fiber. The top food sources of solid fats in the United States are foods that are processed and include grain-based desserts (11% of all solid fat intake); pizza (9%); regular (full-fat) cheese (8%); sausage, franks, bacon, and ribs (7%); and fried white potatoes (5%). The guidelines state that no more than 10% of total daily calories should come from saturated fats but emphasize trying to consume less than 7%.
Consumers deciding on food purchases need to take a number of factors into consideration when choosing between whole or processed foods:
There are many documented risks of eating a diet that is based on processed foods over whole foods. Research has linked an increased risk of cardiovascular disease, diabetes, and cancer with a high consumption of processed meats, especially meat processed with nitrates/nitrites. High sugar intake increases risk for dental caries, and consuming large amounts of saturated fats has a strong link to increasing both total cholesterol and low-density lipoprotein (LDL, or “bad”) cholesterol, which both increase the risk of developing cardiovascular disease. People with hypertension, diabetes, or chronic kidney disease must eat a diet low in sodium, which is difficult to achieve if eating processed foods. Much evidence has documented a link between decreased sodium intake and lowered blood pressure. The Dietary Approaches to Stop Hypertension (DASH diet) is an eating plan that is based mostly on whole foods to help reduce high blood pressure. Having elevated blood pressure above the normal range increases an individual's risk of cardiovascular disease, congestive heart failure, and kidney disease.
Risks from whole foods include:
The risks of consuming processed foods include:
Parents may need to consult with a doctor or registered dietitian to make sure that children or other dependent people in their care are eating a variety of healthful foods, whether whole or processed; that the foods are properly stored and prepared; that the person is not purchasing or consuming foods excluded by a special diet; and that junk foods are kept to a minimum.
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Rebecca J. Frey, PhD
Revised by Megan Porter, RD