Diet

Diet is the food and drink that a person takes regularly day after day. The word diet also refers to the amounts or kinds of food needed under special circumstances, such as losing or gaining weight. Dietary needs vary ac­cording to age, weight, condition of health, climate, and amount of activity. Dietetics is the science of feeding in­dividuals or groups. The money available and health and nutritional needs affect the type of feeding prescribed.

Normal diet, or balanced diet, contains all the food elements needed to keep healthy. A person needs min­erals, proteins, vitamins, and certain fats to build and maintain tissues and to regulate body functions. Pro­teins, fats, and carbohydrates are used to provide energy and heat. A diet that lacks any needed food ele­ment may cause certain deficiency diseases. For exam­ple, lack of vitamin C causes scurvy, and lack of iron, fo­late [a B-vitamin), or vitamin B,₂ causes anaemia (see Anaemia; Scurvy).

Diets for losing or gaining weight. Both the energy value of food and the energy spent in daily activity are measured in units of heat called kilocalories. These measurements are also referred to as food calories, or simply calories (see Calorie). Diets for gaining or losing weight are based on the amount of calories taken into the body in food and the amount of calories used up in activity. If people take in more calories than they use up, they will gain weight. They will lose weight if they take in fewer calories than they use up. A diet aimed toward losing or gaining weight should include all the food ele­ments. People should seek the advice of a doctor before beginning such a diet.

Special diets may be prescribed for people suffering from certain diseases. For example, the healthy body needs sugar, but a person with diabetes must limit the use of sugar. Doctors may prescribe low-salt diets for patients with certain heart or kidney diseases.

Some people suffer allergic or skin reactions from certain food products, such as milk, tomatoes, strawber­ries, wheat, potatoes, eggs, fish, nuts, chocolate, or pork. These people should consult a doctor.

Certain groups of people, such as young children or older people, have special dietary needs. Because chil­dren grow rapidly, they need food not only to replace worn-out tissues and provide energy, but also to build new tissue. A well-balanced diet for a child or an adult should include milk and milk products; eggs, lean meat, poultry, fish; or nuts, seeds, and legumes, such as peas and soybeans; fruit and vegetables; and cereals or bread products. Older people need as many nutrients as chil­dren and young adults. But if their activity is reduced, they need fewer calories. Expectant or nursing mothers and babies also need special diets (see Baby [The ex­pectant mother; Feeding procedures]).

Related articles: Allergy, Fat, Metabolism, Calorie, Food, Nutrition, Carbohydrate, Fruit (introduction), Protein, Cooking, Health, Vitamin, Digestive system, Lipid, and Weight control