Performance enhancement in perspective

There are countless nutritional products aimed at the sportsperson, which claim to have some performance-enhancing ability. These substances, called `ergogenic aids', theoretically improve performance to a point above that obtainable through a good training programme. Athletes are very susceptible to any claims for even the slightest improvement in performance, as fractions of a second could mean the difference between winning or losing.

Many ergogenic aids are basically expensive forms of proteins, minerals and vitamins. Their effectiveness is often unproven, based on folklore and reliant on the ignorance of the consumer (for example, substances such as Royal Jelly and wheat germ oil). On the other hand, some performance-enhancing principles are based on reputable scientific evidence that have been shown to improve performance in the laboratory (such as carbohydrate supercompensation - see overleaf).

However, it is interesting that even in cases where the supplement or _special diet has no physical basis, an athlete can sometimes gain purely psychological benefit from consuming something he or she believes in.

Proteins and amino acids

Although certain athletes may need an increased amount of protein, taking excessive amounts in the form of powdered or liquid supplements is unnecessary. Despite the claims of manufacturers, large quantities of protein will have no beneficial effects on muscle growth, strength or on performance. Any excess will simply be used as an energy source or stored as fat. In addition, kidney function may be hampered and dehydration caused as a result of taking in too much protein.

The supplements currently in vogue - especially among body builders and weight lifters - are amino acids, the 'building blocks' of proteins. The theory is that certain amino acids stimulate growth hormones. The increase however is slight and has no practical effect. Amino acids are not 'fat burners' or detoxifiers as has been claimed. Although tablets taken for this purpose are extremely expensive, the amount of amino acids in them is very small. In fact, a single egg contains far more than that found in seven or more amino acid tablets!

Vitamins and minerals

As mentioned earlier in this chapter, supplementing vitamins and minerals has no performance-enhancing properties in an athlete whose normal diet is not deficient. The effects of taking megadoses of certain vitamins may even impair performance.

Manufacturers and quasi-nutritionists have given certain substances vitamin status, although they are not scientifically classified as vitamins. For example, pangamic acid (otherwise known as vitamin B15) supposedly prevents various diseases, slows the ageing process and improves physical performance. None of these claims has been substantiated. Laetrile or vitamin B17 is a source of cyanide and has been banned. Other `pseudovitamins' are orotic acid (vitamin B13), bioflavenoids and vitamin B-T (or carnitine), all of which do not function as vitamins.

Carbohydrate loading

`Carbo-loading' is a phrase which has passed into common use. It has been proved scientifically that carbohydrate loading (otherwise known as carbohydrate supercompensation) is one of the practices which is effective in improving performance. It may be explained in the following way: Exercise which lasts for longer than 60-90 minutes is dependent on the amount of glucose available. Glycogen (glucose) stores in the muscle and liver are small, so enlarging them allows an athlete to continue exercising at a higher intensity for longer. A carbohydrate-loading programme increases the amount of muscle glycogen stored before you need to use it.

The best method of doing this is to gradually reduce the amount of training you do during the six days preceding an event and, during the final three days, eat a diet that is high in carbohydrate (500-600 grams per day). The extra glycogen stored in this way allows the athlete to continue exercising for longer.

Carbohydrates, fluids and sodium during exercise

It has been proved that supplying the body with carbohydrate during endurance-type exercise has a glycogen sparing effect which allows an athlete to exercise for longer. Many studies have been done in attempts to find a solution that will allow the maximum amount of water to be absorbed, while at the same time providing an optimal amount of carbohydrate. So far, it seems that a form of carbohydrate known as 'glucose polymers' has the best absorption rate. These are chains of glucose molecules linked together. A solution containing about 10 per cent carbohydrate in the form of glucose polymers supplies the most glucose to the body during exercise, and at the same time provides sufficient water replacement. (It is important to remember that a carbohydrate solution is only of benefit during prolonged exercise.)

Adding sodium to replacement fluids increases the concentration of the fluid. It was initially thought that this would hamper the absorption of the fluid, but the most recent findings suggest that the addition of a very small amount of salt (1-2 grams per litre) is in fact necessary for absorption.

Alcohol

Not surprisingly, it has been proved that alcohol has no beneficial effect on exercise. In reality alcohol is a depressant that slows reaction time, impairs muscle reflexes and disturbs coordination. In addition, it causes dehydration which interferes with fluid balance and has a negative effect on performance.

Caffeine

Some athletes use caffeine as a stimulant and to increase the amount of free fatty acids in the blood. Theoretically, more fat is then available to be used for energy, resulting in glycogen sparing (see above). However, an excessive amount of caffeine is necessary to produce this effect and, apart from the fact that a very high concentration of it in the urine can disqualify a competitive athlete, there are several other disadvantages to using caffeine in this way. The main one is that it has a diuretic effect, which results in increased fluid losses and a greater risk of dehydration. In addition, overconsumption of caffeine can result in headaches and nausea and it is therefore not advisable to use large doses of this stimulant in an attempt to enhance performance.

Other imposters

Royal jelly, wheat germ oil, ginseng, extracts of various herbs and numerous other products have all at one time or another been touted as performance-enhancers. The truth is, however, that the only possible effect most of these substances could have would be a psychological one.

What kind of carbohydrate? continue...

Protein

The amount of protein needed by athletes is a controversial subject which has been debated for many years. Traditionally, weightlifters and athletes in other 'power' sports have believed that consuming vast quantities of protein will enhance muscle development. On the other hand, scientists have generally maintained that the protein needs of all athletes can be met by the same recommended daily allowances (RDA) as those for sedentary individuals.

Many research studies over the past decade have not resolved the controversy. However, as a very small amount of protein is used for energy during endurance sports, certain researchers now believe that the RDA of 0,8 grams per kilogram body mass per day might be insufficient for those who are involved in endurance-type exercise. Some (but not all) studies also seem to indicate that exercise which needs a good deal of strength (such as weight-lifting) may increase protein requirements. At the same time, there is no evidence that excessive amounts of protein (such as the 2-2,5 grams per kilogram body mass, per day commonly consumed by power trainers) will have any added benefit.

How much protein does an athlete in fact require? While there are no definite recommendations, studies have suggested this may be between 1 and 1,5 grams per kilogram body mass per day or 12 to 15%of the total energy intake. But before you reach for that protein _supplement, it must be emphasised that protein deficiencies among athletes are extremely rare. For example, a diet consisting of 14 300 kilojoules (3 400 calories), 14 % of which is derived from protein, provides about 119 grams of protein. An athlete who weighs 80 kg will therefore consume about 1,5^-grams of protein per kilogram per day. This diet is thus quite capable of supplying the increased protein requirements of strenuous physical activity.

Vitamins

Vitamins play an important role in regulating and assisting the breaking down of macronutrients for energy production and muscular contraction, as well as the formation of red blood cells. All of these functions are essential in exercise performance. Two questions are usually asked when looking at the vitamin-exercise connection:

• Does exercise affect vitamin requirements?
• Does vitamin supplementation improve exercise performance?

Vitamin requirements depend on the energy source of the working muscle. Exercise has been shown to increase the need for vitamin C and riboflavin (vitamin B2). However, it has also been proved that supplementation fails to increase the ability of athletes to train. Low thiamine (vitamin B1) intakes show no measurable effect on performance. Vitamin deficiencies in sportsmen and women are very uncommon and any increased demand for vitamins is usually met simply by the increased overall energy intake of the athlete. Studies of the effects of vitamin supplementation on performance have consistently found that there is no improvement in performance in athletes who have a balanced diet with an adequate vitamin intake. However, special care must be taken by those athletes who consume less than 5 000 kJ (1 200 cal) per day to ensure that their diets contain enough in the way of vitamins. This low energy intake is more common among female endurance athletes and ballet dancers.

Minerals

Like vitamins, minerals play an essential role in various exercise- related functions. The most important macrominerals and trace elements in an athlete's diet are sodium, potassium, magnesium, calcium and iron.

Sodium and potassium, which are usually referred to as 'electrolytes', play a major role in the amount of fluid in the body. Trivial amounts of both are lost in sweat, but even those athletes who sweat excessively rarely need to supplement their diets with either salt (sodium chloride) or potassium. The average diet contains 3 to 4 times more salt than necessary and simply by eating sufficient fresh fruit and vegetables, our potassium requirements are easily met. Magnesium deficiency is rare in athletes, partly due to the fact that it occurs in many foods and partly because sweat losses are very small. Magnesium does play an important role in the formation of glycogen, the storage form of carbohydrate in muscles and the liver.

Iron plays a major role in relation to exercise. The lack of it is the most common nutritional deficiency in the world and the most important in relation to runners, especially female runners. Energy intakes of less than 5 000 kJ (1 200 cal) are not enough to supply the amount of iron which a female sportswoman needs. Iron supplementation may then be necessary.

Water

Water can also be referred to as a nutrient as it is so essential to life. One of its many functions in exercise is that of heat regulation. The amount of water needed during an exercise event depends mainly on the duration and intensity of the exercise and the body weight of the athlete. As a general guide, 500 ml per hour is thought to cover most athletes' requirements.

What kind of carbohydrate?

Athletes often don't know what form of carbohydrate they should be consuming. Does it make a difference if you eat carbohydrate mostly in the form of sugar or should you eat only complex carbohydrates (such as bread, pasta, rice, cereals and potatoes)? Some people regard sugar as 'deadly', while others wouldn't do without it and consider it a necessary part of their diets. Nutritionists advise that sugar and sugary foods should be limited to between 5 and 10 % of total daily energy intake. In other words, a moderate amount of sugar and sugary foods is not considered harmful. The higher the energy content of your diet, the larger the quantity of sugar you can eat. However, sugar and foods containing a large amount of sugar should never take the place of unrefined complex carbohydrates such as wholewheat bread, whole grain cereals and sweetcorn, as these supply other vital nutrients which sugar does not.

Sugar is a useful addition to the diets of athletes who need large amounts of energy, as it supplies a 'calorie-dense' food source. Athletes who take part in triathlons, for example, may find that they simply do not have the time when training two to three times a day to eat the amount of food they need to perform well. By including a small amount of calorie-dense foods - such as those rich in sugar - in their diets, these triathletes are able to fulfill their energy requirements without spending all their free time eating! However, those athletes who try to maintain very low body weights and who consequently eat very little, should obviously keep sugar and foods high in sugar to a minimum.

The fibre factor

Fibre, though not classed as a nutrient, and not actually absorbed by the body, is an important component of our diets, whether we are athletes or sedentary individuals. Found exclusively in plant foods, a low intake of fibre has been linked to various 'Western' diseases. Much of the natural fibre in plant foods is lost in food refinement and this together with a high consumption of animal foods, results in the average Westernized diet being low in fibre. We should all aim to eat at least 30 grams of fibre per day.

Fat

Fat is the other nutrient that is a chief source of energy in our diets. Athletes and the public in general should aim to consume no more than 30% of their total daily energy in the form of fat. Endurance athletes who consume between 60 to 70 % of their energy in the form of carbohydrates, may have to limit their fat intake to 20-25 % of their total calories to allow for those calories obtained from carbohydrates and protein. The main advantage of fat is that it is a very concentrated source of energy (9 calories/37,8 kilojoules per gram). When fat is used as a source of fuel during exercise, it has the advantage of 'sparing' glycogen. A diet high in saturated fat and cholesterol can cause raised blood cholesterol levels, even in athletes who train vigorously, so both should play a limited role in any diet.

Junk Foods, Sugar, and Violence

My little great-nephew Alex (the one who became a vegetarian at four years old) has a horrifying reaction to sugar. Within minutes of consuming even small amounts—in drinks or food—a charming little boy becomes an uncontrollable child, shouting and even hitting people. And it seems that he is one of many, as several of his friends at school are also on sugar-free diets.

My son Grub has a friend who was diagnosed with bipolar personality disorder. As he is a very large man there were times when his behavior was frightening—he actually chased his father around the kitchen table with a knife during one of his manic episodes. It was just after this that Grub read an article about the effect of sugar on the metabolism of some people, and convinced his friend to cut out sugar from his diet. The result was amazing—he became a much calmer person immediately. So I was fascinated to read about a study linking sugar and violence among prisoners.

Stephen J. Schoenthaler, Ph.D., a sociology professor at the Stanislaus campus of California State University, had a hunch there was a link between three alarming statistical curves: the number of incidences of useless violence, the increased consumption of fast foods, and the increased consumption of processed sugars. He convinced a large-scale prison facility in Virginia to help him conduct a study with inmates. Initially the prisoners were fed a typical American diet that included white bread, hamburgers, sausages, fried potatoes, cookies, sweet snacks, and soft drinks. After a few days they were switched to a whole food diet that included plenty of fresh vegetables, fruits, whole meal bread, as well as fish and lean meats.

The results were remarkable. Once they moved on to healthy foods, behavior problems, such as violence and verbal abusiveness, immediately decreased. When they were switched back to the soft drinks and fatty foods, behavior problems returned. The findings created a stir in the national prison network, and Schoenthaler became a much sought after nutritional advisor. He also conducted an interesting study with approximately 8,000 teenagers at nine juvenile correctional facilities. In each site, the standard diet—high in sugar and other refined carbohydrates—was switched to include plenty of fruits, vegetables, and whole grains, as well as vitamins and mineral supplements. During that year, the facilities reported that the incidence of physical violence, verbal abuse, and escape and suicide attempts decreased by almost half.

After twenty years of studying nutrition and behavior at juvenile and adult correctional facilities and in public schools, Schoenthaler is now convinced that the effects of diet are so powerful that everyone should be held responsible for what they eat, just as they are for what they drink when driving. Which means we must do a better and better job of educating people, and ensuring that all these junk foods that we know are causing so many problems are removed from the stores and from our kitchen cupboards.

WASTE NOT, WANT NOT

One of the main threats to our health and the health of our planet is overconsumption. More than a billion of the most poverty-stricken people in the world are suffering and in some cases dying from lack of enough food. Meanwhile, it's estimated that a billion of the wealthiest people in the world are at risk of debilitating diseases and death partly because they are eating too much of the wrong kinds of food.

A person living in an industrialized country consumes, on average, twice as much grain, three times as much meat, nine times as much paper, and eleven times as much gasoline as someone in a developing country, according to the World Resources Institute. With all this consumption comes a huge amount of waste. Timothy W. Jones, an anthropologist at the University of Arizona, spent ten years studying food waste, examining farms and orchards, warehouses and retail outlets, dining rooms and landfills. His research shows that an average family of four currently tosses out $590 per year in meat, fruits, vegetables, and grain products. Nationwide, he says, household food waste alone adds up to $43 billion.

When I first returned from Tanzania, having experienced true poverty firsthand, to the so-called developed world, the thing that utterly shocked me was the waste. The waste of packaging. The throw-away this, that, and the other. And the waste of food. That was the greatest shock of all. The size of the portions of food served, especially in America. The amount left over in restaurants, after school meals, in the homes I visited. And the reason for my distress was not only that I had just spent many years living among people who had almost nothing, but also because I can never forget the lean war years of my childhood. We were taught that waste was one of the greatest sins.

WHAT YOU CAN DO

Tempting and convenient as it can be, we should all avoid fast foods whenever possible and I certainly have given you plenty of incentive for doing so. Each one of us can also make a concerted effort to create as little waste as possible, each day. We can remember to start with smaller piles of food on our plates and ask for reduced portions at social gatherings and restaurants. We can always order more food or go back for seconds. Why not begin small and keep adding if you are still hungry?

When we bring groups of students together for a Roots & Shoots summit, we provide buckets for recycling various waste products, including food. After the first meal we carefully weigh this bucket of food scraps. The kids are horrified when they realize how much they have put on their plates, only to throw it out afterward. The amount of waste is then equated to how long that amount of food would feed a family living in poverty.

If you have a garden, you can make compost from food waste, as we do at my home in Bournemouth. But you can compost even if you do not have a garden. I met a group of youngsters from South Central Los Angeles, in the inner city, who collected food scraps from local residents, and broke it down by using worms. This is known as vermiculture—which can actually be located in the living room for there is no smell! Moreover, it gives the very best quality soil, which the children sold to local parks and greenhouses. They had created a flourishing business!