Study Guide to Accompany NASM Essentials of Sports Performance Training
Sport diet guide
Whatever your sport, nutrition should be an integral part of your training and competition strategy. Although the emphasis will vary according to the activity you're involved in, there is a consensus among sports scientists on guidelines that athletes should be aiming for.
The International Conference on Foods, Nutrition and Sports in Lausanne (1991) agreed the following nutrient intakes to be optimum for most sports: 60-70% of calories in the diet from carbohydrates, 12% from protein and the remainder (18-28%) from fat. This in effect means eating a diet far higher in carbohydrate and lower in fat and protein than average.
Later in this article we will go on to consider detailed requirements for different types of sports activity. But first, we'll take a look at the three key ingredients in sports nutrition: carbohydrates, fluid and iron.
The carbohydrate connection
Carbohydrate is a crucial fuel for exercise. The body makes its own carbohydrate store, known as glycogen, which is stashed away in the liver and muscles. Glycogen is the body's fuel of choice for any exercise more intense than a gentle jog. This is because it can be broken down to provide energy more quickly than fat (the body's other major energy store). However, the snag with glycogen is that only limited amounts of it can be stored. This means that regular training, as well as competition where activity is at least an hour long, carries the risk of glycogen depletion. Low glycogen stores will mean a more sluggish performance and an increased risk of injury.
Strategies to minimise this problem include carbohydrate loading (see box, and the following article), ensuring that a high-carbohydrate diet is eaten the whole time during training to avoid burnout; also, consuming carbohydrates during exercise (eg, a cycle ride) or between rounds (eg, a tennis tournament) can cut down on glycogen loss and keep performance boosted.
Thrive: The Vegan Nutrition Guide to Optimal Performance in Sports and Life
If you're in regular training, eating lots of carbohydrate-rich foods will encourage your body to store glycogen (see Table I for carbo contents of various foods). A guideline to aim for is 8-lOg carbohydrate per kg of body weight per day. For an average man (70kg), this would mean aiming for a daily intake of 560-700g; for an average woman (55kg), between 440-550g. Tips for boosting your carbo intake The twin strategies are to cut back on fat and to increase carbohydrates:
1 Base meals around carbohydrate foods - potatoes, pasta, rice, bread.
2 Eat smaller portions of fat-rich foods (eg meat, pies, cheese) and fill up with extra potatoes or bread.
3 Porridge made with water makes a high-carbohydrate start to the day.
4 Drink fruit juice with meals, and a milky drink at bedtime.
5 Cut bread extra-thick for sandwiches.
6 Try carbohydrate-rich snacks that are also low in fat: eg fresh or dried fruit, water biscuits spread with jam.
7 Choose pasta sauces based on tomatoes or vegetables rather than meat or cheese.
Timing your carbo intake
If you need to replenish your glycogen stores quickly (eg you're training every one or two days) it's best to take advantage of the fact that the body is more likely to make glycogen immediately AFTER exercising - the sooner, the better. Some foods are better than others for this - the best are those with a high 'glycaemic index' (a term which means they will bring about a large surge in blood sugar). Examples of such foods are: bread (white or wholemeal), rice, potatoes, raisins, bananas, glucose, sucrose and honey. If you can't face eating straight after exercising, try a carbo-rich drink instead.