Food is the main source of energy and nourishment for animals and humans. It is essential for growth and repair of body tissues. Food contains vitamins, minerals and other nutrients necessary for life. However, many people in developed countries have diets that are too high in fats and salt and low in fruits and vegetables. Consequently, malnutrition is a serious problem in many parts of the world.
Among the major sources of food are plants, animals and fats. Fats provide twice as much energy as carbohydrates and are important for the protection of internal organs. Animal fats include butter, lard and milk. They are also used in cooking. Other common fats are vegetable oils, such as corn oil, soybean, rapeseed, and cottonseed.
Several hundred GRAS substances, including sugar, sodium, salt and spices, have been approved for use in foods. These are considered safe by experts.
Some food additives are intended to improve the consistency, flavour, appearance, and shelf life of the product. Others, such as colouring agents, are designed to offset the loss of natural colour.
A list of all ingredients is required on any packaged food. The first ingredient listed is usually the one that is present in the highest proportion by weight. For example, chocolate is made from cocoa, cocoa butter, and sugar. Similarly, the last ingredient on a label is the one that is present in the smallest proportion by weight.
Most of the food that is consumed by consumers is packaged. Many of these packaged foods are regulated by the USDA and must meet targets set for each food group. Depending on the type of food, the targets may be expressed as the percentage of characterising ingredients, the quantity of nutrients per serve, or the number of calories for each serving. In addition to providing nutritional value, most foods need to be non-perishable.
Foods that are processed are also regulated by the FDA. Products that have been processed are allowed to have coloring agents, flavorings, and preservatives. All of these are permitted colors, as long as they are subject to rigorous safety standards.
While most packaged foods are required to show the percentage of characterising ingredients, some of these products do not have to list them. Manufacturers may choose to use a variety of ingredients, and some ingredients are considered compound ingredients, as they are a result of a combination of other ingredients.
One reason that the number of food additives has increased is that manufacturers must meet consumer demands for tasty, non-perishable, and affordable foods. This is especially true in a developing country where famine is a real possibility.
Some food additives are approved by the FDA and are called GRAS ingredients. These substances are based on published scientific evidence and are considered safe by health experts. Besides improving the texture and appearance of a product, these compounds are used to control acidity, alkalinity, and stabilisers.
During the industrialisation period, many of the food products that were produced were adulterated. The process was common, but few scientific means were available to detect such alterations.