Australian scientists were the first in the world to apply the concept of the glycaemic index to sport and exercise. Canadian scientists invented the G.I. Approach to help classify carbohydrates but Australian researchers could see that what they were doing had important implications for sporting performance. The rest of the world is still catching up. Manipulating the G.I. of the diet can give you the winning edge—whether you are one of the elite or a weekend warrior.

Misconceptions about carbohydrates. In the past we were taught that simple carbohydrates (sugars) were digested and absorbed rapidly while complex carbohydrates (starches) were digested slowly. We assumed (completely incorrectly) that simple carbohydrates gave the most rapid rises in blood sugar while complex carbohydrates produced gradual rises. Unfortunately, these assumptions had no factual or scientific basis. They were based on structural considerations, smaller molecules, like sugars, being thought to be easier to digest than larger ones, like starches. Even though incorrect, the logical nature of these assumptions meant that they were rarely ever questioned.

*112\42\4*

The controversy about the influences of nature versus nurture has been going on for centuries. The last 20 years of the 20th century have seen tremendous advances in molecular sciences, which have enabled a greater appreciation of the importance of genetics in many areas of human biology. The human-genome project, which commenced in the 1980s, plans to map all human genes (a directory that will provide genetic ‘addresses’ equivalent to about eight major city phone books) by the year 2010. In the end, it is likely that what will be proven is what we have always known, that parents are responsible for a lot, including the degree of body fatness in their children. On the other hand, genetic influences do not necessarily imply predetermination. The influence of a genotype (the genetic ‘blueprint’) which favours obesity will only be translated into the phenotype (the manifest characteristics of the genotype of an obese person) under certain conditions. Unlike having blue eyes or fair hair, the genetic expression of fatness is only manifest given the right conditions. In other words, an environment which favours energy surplus is virtually a prerequisite for the obesity genes to show themselves.

The studies of genotype and body fat are usually based on comparisons of body size in families and some of the most informative studies involve twins. Identical twins share 100 per cent of their genes, whereas non identical twins only share 50 per cent of their genes. By comparing the similarities in body size between the two types of twins, an estimate of the genetic contribution can be made. Three major twin studies carried out in the late 1980s showed some startling findings, in particular, amazing similarities in body fatness and body shape in identical twins who had been reared apart since birth, some never even having met! In general, genes explain about 25-40 per cent of the variation in body fatness, although it has to be remembered that these estimates are based on people living in fairly similar environments.

Some of the most significant research in this area has come from Professor Claude Bouchard and his group at Laval University in Quebec. Their experiments are carried out with pairs of twins who are kept in comfortable holiday-type accommodation for months at a time, and compare responses to various eating and exercise regimes. Their findings confirm that there is a wide range of responses to identical environmental influences and that the degree of response (such as the degree of weight gained for a given calorie excess) is largely genetically determined.

Genetic influences are unlikely to be the result of a single ‘fat gene’. Genes probably influence all aspects of energy balance including food preferences, nutrient digestion and processing, fat burning and storage and physical activity levels. In fact, to the mid-1990s, a total of 24 genes had been specifically identified as related to some aspect of obesity, but scientists believe several hundreds more are likely to be involved.

One key factor which appears to be at least partly inherited, for example, is food preference. Researchers at the University of Cincinnati examined preferences for 17 different types of foods ranging from fruit to snacks, chips and hamburgers. Comparisons were made between young (9-18-year-old) identical and non-identical twins living together. Frequency of eating and preferences for different foods were rated on a series of scales which indicated that genetic factors (e.g. in identical twins) do, indeed, appear to account for certain food preferences. The main heritable factor in preference appears to be sensitivity to, and preference for, bitter compounds in foods. Preferences for orange juice, broccoli, cottage cheese, chicken, sweetened cereal and hamburgers, for example, all appear to have a hereditary component.

*176\186\4*

Energy in the biological cycle originates from the sun. Plants convert solar energy to chemical energy through a process called photosynthesis. Humans then eat plants and/or animals which also eat plants. From these we obtain the calorie/containing components or macronutrients known as carbohydrates, proteins, fats and alcohol, which contain stored energy. These are then broken down by the body’s cells to provide energy. The thickness of the arrows also illustrates the ease with which each nutrient is converted to energy or stored as fat in fat cells, a thicker arrow indicating easier conversion.

The body’s cells trap the chemical energy released from food in a high-energy compound known as adenosine triphosphate (ATP) which is stored in small quantities in every cell. When energy is needed (say to transport glucose into the cell), the ATP gets broken down to adenosine diphosphate (ADP), thereby releasing the energy needed for the cell’s processes.

Energy derived from fat, carbohydrate, a protein and alcohol is used in the body for catabolic processes which are involved in the break down of cell tissue and for anabolic processes which build up cell tissue. If protein is called upon to fuel these processes, the basic protein units (.amino acids) are first converted to glucose through a process called gluconeogenesis. In addition to supplying the energy for these processes, the four nutrients, but especially protein, can also be the building blocks for growth, such as when muscle size increases with exercise. The sum total of energetic events which occur in the body, i.e. anabolism plus catabolism, is known as metabolism.

To provide the energy for these events, the body has three major reserve energy stores; glucose which is stored in the liver and muscle as glycogen, protein which is stored primarily in muscle, and fat, the majority of which is stored as depot fat, subcutaneously, around the internal organs and intramuscularly.

Eventually all energy is reduced to heat, therefore the energy produced by living organisms is measured in terms of heat production as kilocalories (kcal). One kilocalorie is defined as the amount of heat energy required to raise 1 kilogram of water 1° Celsius (C) at 15°C. The energy values of food are measured in a similar way through direct calorimetry where a food item is placed in a chamber called a ‘bomb calorimeter’ and combusted in a vat of water. Using the conversion formula above, the rise in water temperature is recorded as kilocalories. The four basic food components have the approximate energy values per gram.

It is important to understand the abbreviations of terms as these are often confused in the popular press. What the lay person usually refers to as T calorie’ is actually 1000 calories’, or 1 kilocalorie’. One real calorie is actually a very small unit, and hence it is multiplied by 1000 to give a kilocalorie (or kcal). This is sometimes also referred to as 1 Calorie (spelt with a capital C). New metric measures also confuse the issue with 1 cal being equivalent to 4.184 joules, or 1 kcal being equal to 4.184 kilojoules (notation ‘kJ’). To round off the figures, 1 kcal is generally regarded as being equal to 4.2 kJ.

*37\186\4*

A hernia means that something is being pushed through a hole. During the last few months of pregnancy, the male baby’s testes which sit close by the kidney begin to descend. They pass via a hole or canal in the front wall of the abdomen, down in the pubic or inguinal region (as it is called) and slip into the scrotum, the sac on each side of the penis, where they remain for the rest of the individual’s life. During this journey, they drag with them a thin sheet of tissue which is continuous with the lining of the abdominal cavity. Normally the canal through which they pass closes up before birth, and the lining, called the tunica vaginalis, seals off around the testes and the rest also simply seals off.

Inguinal hernias

Occasionally, things do not go as planned. The tiny canal may not close off. Also, the lining may not seal off. This means that both are open. The result is that the contents of the abdominal cavity may be forced through the canal into the scrotal sac. In minor cases, this will appear as a bulge in the groin. It is usually worse with standing, coughing or straining (for example, when a bowel action is occurring). Often the material flows back and forth through the hole, vanishing if the boy lies down. But sometimes in bigger hernias, the material may penetrate right down to the scrotal sac, and it may stay there.

The main fear is that it may gradually swell and be trapped by the neck of the canal which suddenly becomes tight. If it is a piece of bowel, a sudden surgical emergency called a bowel obstruction may occur. Food is no longer able to pass along the bowel. The blood supply may be cut off. Unless there is an operation immediately, the bowel may turn gangrenous and the boy become acutely and dangerously ill.

Incarceration is the term given to a hernia that will not easily slip back into the body. Obstruction occurs when the passage of food is blocked. Both are serious and need prompt medical attention.

If there is a visible inguinal hernia on the left side, there is a 50 per cent chance there will also be one on the right side, even though it may have not yet put in appearance. On the other hand, for some strange reason, if there is a hernia on the right side, there is only a 10 per cent chance that a hernial sac will be present on the left side too! Don’t ask why—nobody knows. It’s just one of those strange quirks of life.

Hernias can also occur in females, and are related to development of the ovaries and their descent. They are most likely to be present on both sides if present.

Treatment of inguinal hernias

There is only one form of treatment for hernias, and that is by surgery. This is usually carried out at a time when the child is in good health. The hernia is reduced (as the doctors say)—that means the contents are pushed back into the abdominal cavity where they belong. The canal is stitched up securely, and usually recurrences do not take place. It is a successful operation and may prevent serious consequences.

If complications have already occurred, and the bowel has become incarcerated and strangulation (obstruction) taken place, it may be a matter of urgency to operate before serious irreversible damage occurs with the bowel.

Sometimes incarceration can be corrected manually by pushing the bowel back towards the abdominal cavity. With strangulation, the abdomen becomes distended, and there is vomiting and the signs of bowel obstruction. Surgery may quickly relieve the symptoms and the condition.

Incarceration is fairly common in children under the age of one year. Strangulation tends to follow incarceration. Any lump noted in the groin should be reported to the doctor promptly. Do not leave it there, hoping it will vanish. Most cases will not, and a serious emergency may occur when most inopportune.

Scrotal swellings (hydrocele)

A swelling in the scrotum is fairly common in babies, particularly the newborn. Fortunately, most disappear on their own accord by the age of six months. Some persist, or may recur during childhood.

The cause is similar to hernias. Instead of sealing off at birth, the tunica vaginalis which surrounds the testes still communicates with the abdominal cavity. The connection may only be minimal, but it allows fluid to accumulate in the scrotum, and the swelling may be large. If a torch is shone into the swelling, it appears as a large fluid-filled bag. Sizes may vary tremendously.

Treatment of hydrocele

Treatment must be carried out by the doctor and the sooner this is done the better. If left, pressure may damage the testes. Simple removal of fluid by a needle will give temporary relief. But in any case that does persist, surgical intervention will bring about a rapid and complete cure. It is not a major operation.

Umbilical (navel) hernia

Another fairly common site for hernias is the navel, referred to then as an umbilical hernia. This means that the umbilical ring has not closed up at birth. Before birth, the baby received nutritional needs and oxygen via the umbilical vessels attached to the placenta. This large organ (which became the afterbirth at the time of confinement) was firmly secured to the side wall of the mother’s womb. It had access to the mother’s blood supply, and here exchanges of food, oxygen and other vital needs took place.

Soon after birth, when the umbilical vessels became redundant and oxygen was received via the baby’s own lungs and food via the baby’s own mouth, the umbilical ring usually closed down. Occasionally this did not happen. So, with a persisting hole present (covered only by an outer layer of skin and some fat), with any straining of the abdomen the contents tend to be forced into the weak area. Therefore, a swelling may occur at the navel.

This is most evident if the child is straining (having a bowel action, or trying to pass urine, or crying or yelling). In fact, the hernia can sometimes become large. Some fearful parents are terrified lest the whole thing explode with an almighty bang. I assure you this never happens. On other occasions, the covering can look awfully thin, and even turn a bit blue.

However, none of the hazardous events occur as might take place with inguinal hernias. No incarceration of the bowel contents, no strangulation, no bowel obstruction. These are seldom if ever reported.

Treatment of umbilical hernias

The treatment consists of not treating it. The majority are cared for by the body itself. The umbilical ring invariably closes down of its own accord, with no interference.

The old ideas of taping the sides together is worthless. Do not shove a marble or a two cent coin into the hole and tape it there either. This idea belongs to the Dark Ages. It has no place in modern medical care, so do not try it.

If the condition seems to be getting worse (which is unusual but occasionally happens), see the doctor. Some instances need a surgical repair. But be directed by the doctor in these matters, and follow the doctor’s advice. The child may be referred to a paediatric surgeon for further investigation.

Other hernias may occasionally occur in other regions, but they are relatively uncommon and unimportant. However, any abnormal swelling in any part of the body (abdomen or elsewhere) should be examined by the doctor. This is a general rule for all parts of the body.

*58\87\2*

Little by little, babies grow up and commence looking around for more solid food to fill their needs. So, at breakfast time gradually phase in soft fruits, such as a banana either mashed with some water or milk or, later on, peeled so that the infant can eat it without your help. (Independence soon sets in!) Also, you may offer some softened cereal or porridge, some of yours to begin with. Try sieving it for the first few days.

Purchasing special baby foods is usually unnecessary, and many are relatively expensive. On the other hand, you may offer the baby these if you wish to, and many different varieties are available. I must admit that my four children all loved their tinned foods, and even now (aged over 21 years) still dig out a tin from the pantry occasionally. As I’ve often said, habits started in babyhood often persist. Food is no exception.

Babies usually love sucking a crust, or piece of toast, or a rusk. Be careful to supervise this and do not leave the baby alone, for a chunk may inadvertently slip down the windpipe and cause trouble.

The baby will soon start using a cup—you can show him the first few times, and he will rapidly follow the idea and soon become expert. Offer water or unsweetened orange juice.

At lunch-time, offer some meat moistened with warm water. Later on, offer a piece of meat to suck. Or perhaps a largish chicken bone with meat hanging to it. Give soft fruit or pieces of vegetable such as tomato. Eggs are very useful and highly nutritious—you may spoon feed the baby with soft-boiled egg, or you may prepare a small sandwich from chopped-up or mashed-up hard-boiled egg.

Evening meals may consist of cooked meat and vegetables. Add minimum or no salt or sugar to the food. If you are cooking the baby’s food with the family meal, take it out first before adding salt or sugar to the rest of the family’s food. It is best to offer vegetables separately, rather than mixed up in a messy hotchpotch. Unsweetened stewed fruit, plain dessert, custards or yoghurt are suitable. The baby will like something to chew on, so offer foods similar to those recommended for lunch-time. Adequate fluids are necessary, so always offer water.

Gradually, as babies thrive and grow longer and heavier, they will want to increase the range and amount of food eaten. They will usually let you know when they are hungry and when they have met their needs. Little by little, their food intake and variety will become very similar to that of the rest of the family. Making a baby part of the family circle is important, and the sooner the child eats the same type of food the better. It is easier for the cook and it means that the baby is gradually taking his or her place in the social setting of the family.

*11\87\2*