Food and Sport

by Leanne Young, Reg. Dietician

Being active is an essential part of a healthy lifestyle and a healthy body. Being active provides many health benefits.

These include:

Increased metabolic rate
Improved lung efficiency and circulation
Toned muscles
Sleep better
Maintains bone strength

Guidelines for healthy eating include the following:

Maintain a healthy body weight by eating well and by daily physical activity;
Eat well by including a variety of foods from each of the four food groups each day;
Vegetable and fruits;
Breads and cereals, preferable wholegrain;
Milk and milk products, preferable low-fat options;
Lean mean, poultry, seafood, eggs or alternatives;
Prepare foods or choose pre-prepared foods drinks and snacks with minimal added fat, especially saturated fat that are low in salt, with little added sugar, limit your intake of high sugar foods;
Drink plenty of liquids each day, especially water;
If choosing to drink alcohol, limit your intake;
Purchase, prepare, cook and store food to ensure food safety.

Increased interest in fitness and health has made people more aware that they can affect their health and physical performance. For professional athletes the quality and quantity of food can enhance performance, help maintain fitness and avoid injuries.
Muscles use glucose as the preferred energy source for exercise. The glucose comes from the body's stores of glycogen. Normal glycogen stores provide enough fuel for about 1.5 hour's running. For events or training sessions longer than this, stores can become depleted. Once your stores of glycogen are exhausted, muscles cannot work efficiently and your performance is reduced. This means that the ideal training diet provides around 55-60 per cent of the kilojoules from carbohydrates. Foods like breads, breakfast cereals, rice, pasta, vegetables and fruit should be a large part of your meals as they are nutritious and filling.

Some suggestions for 'carbo boosting' meals:

Baked potato with vegetable filling;
Baked beans or spaghetti on toast;
Chilli con carne;
Sushi;
Pasta with tomato and vegetable sauce;
Breakfast cereal with low fat milk and fruit;
Fresh fruit salad and low fat yoghurt.

As some athletes are training for long periods of time they burn up a lot of energy, some sugar-containing foods and drinks can be added to the diet. These are an advantage because they are not as bulky or filling so it is easier to top up carbohydrate intake with them. The typical NZ diet has only 45-47 per cent of kilojoules coming from carbohydrate which may not be enough to replenish glycogen stores adequately for an athlete.

Glycaemic Index (GI)
As carbohydrate foods are digested glucose is released from the food into the bloodstream. Different foods have different effects on blood glucose levels. Glycaemic Index is a ranking of foods that tells us whether a food will raise blood sugar levels dramatically, moderately or just a little. An athlete can include low GI foods to delay fatigue and supply slow-release energy such as baked beans, low fat yoghurt, rolled oats pasta or apple before an event. After exercise, high GI foods such as sports drinks, breads or rice bubbles can help to replenish glycogen stores in the muscles faster.

Fluids
It is really important to make sure you drink enough fluids. Drinking at least 6-8 glasses of water a day is ideal but if you are exercising you will need even more. Athletes who lose a lot of body fluid risk not only limiting their performance but also over heating, dehydration and heat stroke. Fluid before, during and after training or competing is essential to replace sweat losses, especially in hot weather. Be well hydrated before activity and replace losses soon afterwards. The amount of sweat lost will vary, depending on a number of factors including, temperature and humidity, the duration and intensity of the sport and the fitness level of the athlete. Remember that thirst is not a reliable indicator of how much fluid your body needs. Drink cool - not icy cold - water or sports drinks past the point of quenching your thirst. Before and during a race drink small amounts at frequent intervals. Afterwards drink as much as you can fit in and keep topping up for a couple of hours. Another tip to remember is that alcohol does not provide hydration; in fact it makes the body more dehydrated.

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