Nutrition before exercise

Studies have shown that eating before exercise can improve performance. The meal, snack or drink consumed before exercise is used to compliment a healthy daily eating plan. This is the last opportunity to top up fuel and fluid stores needed for exercise. It is important that you test the pre-exercise food or drink before major events so that you feel comfortable and confident for the race. Remember that food eaten before exercise is only useful once it has been digested and absorbed. This means you need to time your food intake so that the fuel becomes available during the exercise period.

Choice of pre-exercise food

The best options are carbohydrate based foods that are low in fibre, low fat and moderate to low protein. These foods are easily digested and are less likely to cause stomach discomfort during the cycle. The time quantity of food consumed also influences time of digestion, large quantities of foods take longer to digest than smaller quantities. You need to experiment to find the timing that best suits your individual needs. A general guide is to have a meal about 3-4 hours before exercise or a lighter snack about 1-2 hours before exercise. If you have a poor appetite from nerves or awkward meal times and are unable to eat a meal or snack, you might a liquid meal or fruit smoothie easier to consume.

Suitable choices for pre-event meals and snacks:

Pre-event snack ideas (1-2 hours before):

·   Banana + water
·   Sports bar / cereal bar + juice
·   Low fibre cereal (e.g. Original ProNutro) + low fat milk + water
·   Oats (higher in fibre but generally well tolerated) + low fat milk + water
·   White/ brown/ rye toast + honey thin spread peanut butter/ marmite + water
·   Liquid meal supplement e.g. Ensure, Nutren Active
·  Homemade fruit smoothie (Low fat milk/ yoghurt+ fruit + oats + fruit juice

Pre-event meal ideas (4 hours before):

·   Low fibre cereal (e.g. Original ProNutro)+ low fat milk +  sliced banana
·   Scrambled egg on toast (white/ brown/ rye) +  fruit juice
·   English muffins + fruit + yoghurt + water
·   Pasta with tomato based sauce + water
·   Sandwiches/ rolls + lean cold meats/ low fat cheese + water
·   Baked potatoes with low fat filling (cottage cheese/ tuna/ lean cold meat)

Remember: Test your snack options before a training session to ensure stomach comfort during a race.

Are foods with a low glycaemic index better?

The type of carbohydrate in food or drinks can have varying affects on blood glucose levels. High glycaemic carbohydrates provide a rapid release of glucose into the blood stream which is short lived while low glycaemic carbohydrates provide a slower release of glucose which is sustained over a longer period of time. It is assumed that low glycaemic carbohydrates consumed in a pre-exercise meal are more useful during exercise as they provide a more sustained release of glucose which delays the onset of hypoglycaemia (low blood glucose levels). However, research on the performance benefits is inconclusive. It is important to remember that many low GI options foods such as muesli, All Bran Flakes, oats, wholegrain bread are high in fibre and are more likely to cause stomach discomfort during exercise.

Possible negative effects of carbohydrate 1 hour before exercise

Having a carbohydrate based drink or snack before exercise appears to be beneficial to performance in most athletes. However, very few athletes experience reactive hypoglycaemia (low blood glucose levels) when consuming carbohydrate less than1 hour before exercise and experience symptoms such as fatigue, shakiness and dizziness. This reaction occurs when insulin levels increase in response to the blood glucose level. Insulin clears glucose from the blood into muscle cells and when this coincides with the start of exercise, blood glucose levels dip. The body will quickly correct this dip without any symptoms, however, some individuals are more sensitive to this drop in blood glucose levels and the symptoms can affect performance. Athletes can overcome these symptoms by:
  • experimenting to find the best time to eat or drink before exercise.
  • consume smaller amounts of carbohydrate to reduce the insulin response.
  • consume a low glycaemic carbohydrate before exercise such as a fruit smoothie, rye toast, small amount of pasta, original Pronutro
  • consume small amounts of carbohydrate, regularly during exercise.


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