Our friend and expert dietitian Leanne Tee gives some valuable advice on carbo loading before a big race.
Because carbohydrates are a critical fuel source during physical activity, it follows that depleting your body’s carbohydrate stores during exercise will result in fatigue and compromised performance. Optimising the way your body stores and uses carbohydrates will help to delay fatigue and improve your performance on race day. Carbohydrate energy is stored as glycogen in your muscles and liver. The goal before an endurance race should be to increase carbohydrate intake and taper exercise so as to ensure that glycogen stores are as high as possible. This is known as carbo loading. Carbo loading is an important strategy for events lasting longer than 90 minutes, such as marathons and prolonged cycling or triathlon races. In these events the same muscle group is typically being used continually and an athlete’s ability to sustain performance would be compromised by the depletion of muscle glycogen stores. It has been estimated that carbo loading may help postpone fatigue and extend the duration of steady exercise by about 20%. It may improve performance over a set distance or workload by about 2% to 3%. However, the common misconception about carbo loading is that you can eat a high-carb meal the night before a race and that this will be enough to optimise your muscle glycogen stores. For carb loading to work effectively you will need to start carbo loading and tapering your training about 3 to 4 days before the event.
Here are the basics:
- Increase your carbohydrate intake 36 to 48 hours before an endurance event:
The recommended intake is about 10g to 12g carbohydrate per kg body weight each day. It is important that you plan your intake carefully so that you do not over-eat, which will leave you feeling bloated and uncomfortable. Note that a small weight gain of about 2kg is normal if you carbo load correctly.
- Over the last 24 hours choose low-fibre sources of carbohydrate:
Choose low fibre carbohydrates 24 hours before the event to avoid possible gastrointestinal discomfort, which can be a huge disadvantage on race day. For example, choose white bread and rolls, wraps, refined crackers (rice cakes, salty crackers and water biscuits), low fibre cereals (corn flakes), instant oats, white pasta, white rice, potato and gnocchi.
- Cut back on fat:
To maximise your carbohydrate intake choose foods that are low in fat. High fat foods take longer to digest and may cause you to feel full. You might then compromise on your carbohydrate intake. A high fat meal can also cause gastric discomfort when eaten in large amounts. For example, avoid creamy and cheesy sauces as well as oily or fried food. Here is an example of a carbo loading menu for a 60 kg athlete (providing 10 g carbohydrate per kg) for one day: It is important to note that carbo loading is not effective or indicated for all individuals, and the best way to determine whether it works for you is to test it with the support of a medical professional while training. To contact a registered dietitian in your area who can assist you with dietary advice specific to your individual needs, visit www.adsa.org.za References and further reading: Burke L, Deakin V (2010). Clinical Sports Nutrition, 4th Ed. McGraw-Hill, Australia.