Some Facts about 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. Diet needs vary according to age, weight, condition of health, climate and amount of activity. Dietetics is the science of feeding individuals or groups. 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, or vitamin B-12 causes anaemia.

There are special diets intended 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 usually referred to as calories. 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.

Your body needs energy, protein, minerals, vitamins and fibre. In order to get all of these it is important to have a varied and balanced diet, and to eat the right amount. Your body ‘burns’ food to get energy: the amount of energy provided by food is measured in units called calories.

How many calories do you need? This depends on your weight and on what you do. When you are asleep, your body uses nearly one calorie an hour for every kilogram of weight. So a person who weighs seventy kilos uses about 560 calories while sleeping for eight hours; in other words, he needs about 1680 calories just to stay alive for 24 hours, even without doing anything. More calories are needed for different activities – from 100 calories an hour for reading or watching TV, to 350 calories an hour for playing football. To calculate the number of calories needed per day for an average person, first find out that person’s ideal weight.

(Your ideal weight is what you should weight. It depends on your height and your build, and it may be very different from your present weight!) Then multiply the correct weight (in kilograms) by 40 for a woman, or 46 for a man. A 57-kilo woman may need about 2300 calories a day – more if she does heavy physical work or a lot of sport, less if she is very inactive.

(B) Here are a few hints to help you succeed in your diet. Read them carefully and do exercises below.