Maximise your marathon chances

Press, 26 May 1984, Page 14

Maximise your marathon chances

Good eating

Janice Bremer DIETITIAN

The thousands of entries for the marathon in Christchurch on Sunday, June 3, has the dietitians’ telephone lines hot with queries on how to secure optimal performance on the day. Hours of pounding the streets to clock up those necessary 100-plus training kilometres each week certainly has the runners seeking to achieve their goals for the marathon — whether it is to finish, to better the last performance or to win. While the winners of the marathon ordeal may be largely determined by their specific training programme, superimposed upon a hereditary endowment to store more muscle glycogen (rapidly available energy) to last the distance while maintaining a fast pace. This stored fuel is derived from food. No health food, nor dietary 7 manipulation, however, will turn a nourished, fit athlete into a superchampion. But glycogen storage, caffeine ingestion (coffee drinking) and hyperhydration (water drinking) may benefit the trained endurance athlete in events of one hour or more — that is, a marathon or half marathon. Fuel supply Our bodies require oxygen to burn food for energy. As the demand for energy increases, as in exercise, the demand for oxygen also increases. The body can only keep up a pace at which breathing enables sufficient oxygen to enter the body to be available to the working muscles. The body can exercise only for periods of less than two minutes exclusively without oxygen. Beyond that, oxygen is required. The requirements for fuel supply during a long race are: (1) An oxygen supply sufficient to enable the intense use of energy to sustain a racing pace. (2) A fuel supply that is readily available for use. (3) A water supply, to dissipate the heat produced by the use of energy, so that continuous perspiration is maintained. Training develops the capacity to breathe in more oxygen, to store more immediately avail-

able fuel, and reduce the risk of overheating. The fuel and water supplies, however, can be influenced by dietary measures. What is glycogen? Glycogen is the storage form of glucose or sugar in the body. It is the energy or fuel supply most efficiently used in intensive exercise because it requires less oxygen. Intense exercise requires glycogen as fuel, while low-intensity exercise can be fuelled by the breakdown of body fats. Most runners are spent when their glycogen is gone. Training raises the level of running speed at which fats can be used, so that very highly trained athletes can burn fat almost as efficiently as glycogen. This means that their glycogen will last longer. Glycogen storage is essential only in events for longer than one hour; or for events of more than two hours. Training for weeks and months before the event improves the over-all capacity to store glycogen. The objective of dietary manipulation is to “superload” the glycogen stores by first depleting them, then refilling them. This process creates a greater level of glycogen (up to two to three times normal) in the muscles than before the depletion. It is a futile exercise if the stores are then not protected or “spared.” Depletion of glycogen stores occurs when: • There is training or heavy physical exercise a few days prior to the event. • Insufficient carbo-

hydrate (starchy and sugar) foods are eaten. • The early race pace is too fast to be easily sustained (gasping for breath). An increase of glycogen stores over the week before a marathon will improve speed and endurance for many runners. “Cargo loading” The early studies on carbohydrate loading involved two phases of diet: a glycogen depleting diet followed by a depleting run then three to four days of a “loading” diet. The first phase of this programme may have the drawbacks of extreme tiredness, irritability, dehydration, and an unpalatable, unhealthy diet — all occurring in the week before the race. Leading sports medicine writers now 7 favour this modified version: (1) On the fourth day before the event (Wednesday) eat light meals, and go for a run of moderate intensity from one to one and a half hours. (2) For the next two days have minimal or no deliberate exercise while eating a diet of foods largely comprising carbohydrates (80 per cent of calories) along with plenty of water. (3) On the day before the marathon (Saturday), rest and continue with the high carbohydrate diet. (4) On the marathon day, have a meal three to four hours before the event and fluids just before and during the event. The “diet” ® Meals should be largely starchy carbohydrate foods ’ — unbuttered bread rolls and low-fat crackers; potatoes, rice, spaghetti, noodles and other pastas cooked without fats; starchy or sweet vegetables such as corn, creamed corn, parsnip, kumara, peas, etc; baked beans, other cooked starchy beans; fruits and fruit juices; grains and breakfast cereals, porridge, low-fat flour products and baking (leave out the butter, try cottage cheese instead). 9 The above meals can be made more palatable with small amounts of sugar — honey, syrup,

jam; low-fat biscuits or cake: condensed milk mayonnaise (without oil); non-fat milk, cottage cheese, low-fat yoghurt and skim milk powder. Salad and green vegetables will be more important for their colour, variety and texture than their nutritional value. © Have only two small servings of animal protein foods each day as lean meat, fish or poultry with the fat removed and without adding cooking fat, rich gravy or sauce. • Fats are to be avoided if possible (certainly no more than two level dessertspoons daily of the spreading or cooking fats:— that is butter, margarine, cream, oil, cooking fats, sour cream, dressings, cream cheese, ice-cream, fried food, sausages, regular home-made type cookies and cakes, scones, nuts, whole milk, fatty meats, fish and chips, pizzas, pastries, Cheddar cheeses. © Drink plenty of fluids — water, fruit juices, coffee, tea. © It is important that over-eating is avoided — eat to satisfy appetite but frequently — up to 8-10 times each day. Do not go hungry. Remember: © This diet is a “therapeutic” venture for the days before the marathon. Although not dangerous, it is not nutritionally sound as a normal training diet, and it need only be suffered for those few days! ® Evidence that the regime has achieved glycogen storage will be an increase in body weight of half to three kilograms (three grams of water is stored with every gram of glycogen which is helpful for body cooling during the race); and some degree of stiffness may occur, but will be worked out during the event and is of assistance in checking the tendency to run too fast early in the race. © A side effect of in-

creased bowel movement comes with this diet. If causing inconvenience this can be reduced by selecting foods lower in fibre, such as white breads, crackers, juices rather than green veges and more refined cereal foods. Menu suggestions for carbohydrate loading: Breakfast Toast and honey/jam, no butter/margarine; Fruit and breakfast cereal with non-fat milk; Mashed potato — no butter — with tomato and onion on toast. Snack Fruit or fruit juice; Watercrackers. cottage cheese and tomato. Lunch Sandwiches of thick bread with cottage cheese, chicken, and salad fillings; Fruit or fruit juice and/or soup with barley or noodles and bread; Crumpets with jam/honey, no butter; Jelly and fruit. Snack Muffin with jam, no butter; Banana sandwich, no butter. Dinner Small serving of grilled chicken, fish or lean meat; large serving, pasta, potato, rice and/or bread; Vegetables as desired; Fruit and/or jelly or cereal and non-fat yoghurt. Snack Plain fruit loaf or sand wiches, but no butter; Fruit and/or fruit juice. Alternative regime This kind of eating is extremely restrictive. It will be unacceptable for many people to eat most of their bread without butter, to avoid fatty foods, eat little meat, and have pasta with vegetables rather than cheese. For these individuals, and those “fun-running” the half-marathon (and

possibly those who are most highly trained) meals comprising largely the carbohydrate-rich foods, with smaller servings of usual animal foods, combined with little physical activity over the two to three days before the marathon will ensure reasonable glycogen stores. Race day Water is the most important dietary factor on race day. For the fullmarathoners fluid intake early in the marathon race is crucial. This reduces the risks of heat exhaustion, the most life-threatening consequence of endurance running. Particularly for those who will run for more than three hours, it is important that these drinks contain some sugar as more fuel is required at this point. These drinks may either be diluted fruit juice (1:3 ratio juice:water) or '/z tsp glucose for every 100 ml of water, to ensure efficient absorption even during the stress of the marathon. The amount of water required for any individual is largely determined by the air temperature and humidity on the day, the degree of training, the diet, and the person’s body weight (heavier weights need more fluids). Half-marathoners undertaking less than two hours running will need fluids only once to three times during the event. Whether these contain sugar is really a matter of personal preference. Warning: Thirst appears too iate to indicate water requirements. Full marathoners must force themselves to drink. The recommendations are a minimum of 100250 ml (Vz-l paper cupful—every 20 to 30 minutes. On a cool June day 100 ml each feed station should be sufficient for well trained runners.

Pre-race meal To ensure no food is left in the stomach or upper bowel to cause nausea, to avoid toilet stops, and oxygen deprivation through continuing digestion, the meal should be: Eaten three to six hours before the event; be nonfatty — no fried foods; not to contain cooked meat or egg dishes; mainly be starchy foods; low in fibre. When selecting a prerace menu the athlete should first choose familiar and desired food along these lines: Fruit juice, stewed fruit, cereal and non-fat milk, white toast and honey (no butter/margarine), coffee and non-fat milk. During the next three hours diluted fruit juice and water should be consumed. Researchers have shown that two cups of coffee one hour before the race cause the release of fatty acids into the blood which the muscles will preferentially use at the start of the race, conserving glycogen. Caution: An excess of coffee can cause dehydration on a hot day or maycause diarrhoea, anxiety, or sleeplessness. A further 200 to 500 millilitres of the suggested glucose solution or diluted fruit juice should also be consumed in the last hour before the race. (Lack of urine in the few hours prerace indicates a need to drink more.) Sugar taken this way, in these diluted drinks, may also spare glycogen early in the race to extend the potential period of intensive effort. However, excessive sugar eating just before the marathon is not recommended. Summary: Arrive at race day well-trained, well-rested, well-slept, well-fed, and drinking plenty of water, diluted glucose drink, or diluted fruit juice.