In an average lifetime you will eat thirty tons of food
From those thirty tons of food your body will derive the building materials it needs both to grow and to repair itself and the energy to keep muscles functioning and organs such as the brain and the liver operating effectively.
Food helps to provide the fuel to keep you warm and to keep your heart pumping.
If you eat too much food then the excess will be turned into fat and stored. The idea of storing food as fat is that if at any time in the future your intake of food is less than your body needs then the stored fat can be used as a reserve supply.
The food that you eat is made up of carbohydrates, fats, proteins, vitamins and minerals.
Carbohydrates have a terrible reputation—particularly among slimmers who always regard them as a threat to dieting success. It is true that some carbohydrates are bad for you.
But other carbohydrates are excellent and essential foodstuffs. If you are going to eat healthily you must know the difference between the good and the bad!
There are three basic types of carbohydrate:
Simple carbohydrates (also known as sugars)
Complex carbohydrates (also known as starches)
Fibre (also known as roughage)
These are the ‘ad carbohydrates—the ones your body can do without. They are full of calories and will provide you with a lot of energy—often very quickly—but by and large they don’t contain anything else of much value. Honey (which is basically a type of sugar) is very much a mysterious exception, and some types of sugar (such as blackstrap molasses) contain a few minerals, but basically sugar is something you can do without.
You should keep your intake of sugar down because sugar causes tooth decay, makes you fat and increases your risk of developing heart disease. There is even evidence now which shows that too much sugar may increase your chances of developing cancer.
Simple carbohydrates—sugars—are broken down very quickly in the body. That is why they provide more or less ‘instant’ energy. Complex carbohydrates—foods such as cereals, pasta, rice, pulses and fruits and vegetables—are digested much more slowly.
You should increase your intake of complex carbohydrates because foods that are rich in starch also tend to contain essentials such as protein, iron and vitamins. They are also often rich in fibre and usually contain relatively few calories. You can easily increase your intake of complex carbohydrates by eating more bread (just buy bread—preferably wholemeal—which tastes good and cut it thicker), more pasta (preferably wholemeal), more pulses (beans and peas), more rice (brown rice is better for you) and more fresh fruit and vegetables. Wholemeal bread and pasta and brown rice are better because they contain more fibre and haven’t had so many of the original vitamins and minerals removed in the manufacturing process. Starchy foods contain a lot of potential energy and also contain a lot of the essential proteins, vitamins and minerals to enable your body to remain healthy and strong.
Your body needs a plentiful and regular supply of roughage. The list of disorders known to be associated with a low fibre diet is constantly growing but already includes cancer, diverticular disease, gallstones, varicose veins and appendicitis. Fibre consists of a number of complex carbohydrates and there are two types: soluble fibre and insoluble fibre. Most foods which contain fibre include both types.
Soluble fibre has two important jobs. First, it forms a sticky substance in your stomach which restricts the amount of fat that your body absorbs from the other food you have eaten. Second, it helps to control the production of insulin (the hormone which controls the level of your blood sugar) and thereby helps to stop you feeling hungry. Soluble fibre is found in most vegetables and fruits, in oats, barley and rye and in pulses such as peas and beans.
Insoluble fibre is found in wheat (and in the bread and cereals which are made from them) and in some vegetables. As you might imagine from the feet that it is insoluble this type of fibre doesn’t turn into a sticky mass but acts like a sponge and simply swells up as it absorbs the liquid in your stomach. It is because it swells up that insoluble fibre helps to make you feel full—and stop you eating so much.
Your body makes its own protein from the amino acids which are in the proteins you eat; it needs protein to grow and to repair damaged tissues. There are twenty-two types of amino acid—all containing nitrogen—in your body. Eight of the amino acids which are used to create adult proteins and ten of the amino acids used to create proteins in children have to be obtained in our diet because our bodies cannot make them. These amino acids are, not surprisingly, known as ‘essential’ amino acids. Any good, balanced diet will contain all the amino acids your body needs—including these ‘essential’ amino acids.
You don’t need to eat meat to get the amino acids your body needs to make protein. Soya beans, seeds and nuts all contain essential ingredients for making protein. Whatever type of protein rich food you eat the protein will be broken down into amino acids which will then be absorbed into your body.
If your diet doesn’t contain enough material to make proteins then the proteins already in your body—usually starting with the ones in your muscles—will be cannibalised to keep you alive. Your body cannot store protein in the same way that it can store fat and so you need a regular supply of protein. If you eat too much protein then the excess is excreted (although some of it will be converted into fat and stored as fat).
You must eat enough protein because:
If you eat too little protein then tissue proteins—particularly muscles—will be broken down.
Protein is essential for growth and for the repair of damaged tissues.
Protein is essential for the production of some enzymes.
But don’t eat too much protein because:
If you eat more protein than your body needs the amino acids in the protein will be broken down and some of the protein will be converted into body fat.
Eating too much protein may also increase the loss of calcium from your body—with an increased risk of osteoporosis developing.
In addition too much protein may put a strain on your liver and kidneys.
Eating too much protein may lead to vitamin deficiency.
Too much protein may produce an increased risk of cancer and heart disease.
Fat has a terrible reputation. The bad image is well deserved. Fat in your diet can cause heart disease and high blood pressure and can increase your chances of having a stroke.
But some fat is essential and the bad reputation that fat has acquired is largely due to the fact that most people eat fat too much of it. Many people get one half of their calorie intake from fat and most people would be healthier if they ate less fat and, in particular, if their consumption of saturated fat was reduced.
In practical terms this means cutting down on the consumption of meat and dairy produce such as milk, cream, butter and cheese for it is these foods which contain large amounts of saturated fat.
There are three types of fatty acid in fat: saturated, unsaturated and polyunsaturated. But different fats contain these three types in different proportions. Saturated fats cause trouble because our bodies cannot digest them properly. The result is that they stay in the blood for a long time, sticking to the inside of the blood vessels. In the end these sticky, indigestible saturated fats clog up the blood vessels—producing a condition called atherosclerosis which leads to high blood pressure, heart disease and strokes. Saturated fats also interfere with the metabolism of other foods and with the removal of wastes. Polyunsaturated fats are much healthier and much more useful.
You can often tell which sort of fat a food contains by looking at it. Foods like butter and lard which are rich in saturated fatty acids are hard at room temperature. Foods containing unsaturated fatty acids tend to be liquid or oily. It is healthier to cook with liquid fats such as sunflower oil or safflower oil (which are rich in polyunsaturated fatty acids) than to cook with solid fats such as lard or butter. (But watch out: palm oil and coconut oil are both plants oils but they do contain quite a lot of saturated fat.)
Cholesterol, which is present in all animal tissues, has some similar properties to fat but is recognised as being potentially dangerous because if the level of cholesterol in your blood reaches too high a concentration it can increase your chances of having a heart attack.
Cholesterol is present in many ordinary foods (cheese, chocolate, cream, eggs, heart kidneys, liver, crab, lobster, brains, caviar) but most of the cholesterol in our bodies comes not from foods that contain cholesterol itself but from other fatty foods.
Your body can make its own cholesterol from saturated fats so if your diet contains a high quantity of saturated fat then your body will make more cholesterol and your blood cholesterol level will probably rise. (Unsaturated fats provide the same amount of energy as saturated fats but tend to reduce blood cholesterol levels).