Eating During Exercise
Excerpt from Nutrition for the Long Run, by Heidi Smith, Sport Dietitian
(A book inspired by Canada Get Fit)
The most effective way to spare glycogen stores and increase endurance is to consume carbohydrates during exercise lasting longer than 90 minutes. Mos of us have enough blycogen to last 1.5 hours of continuous high intensity exercise. However, after 90 minutes without a source of carbohydrate from food or drink, complete exhaustion is just around the corner. Complete exhaustion is also known as “bonking” or “hitting the wall”. To avoid “The Wall” aim to consume 0.7 – 1 gram of carbohydrate per kg. of body weight per hour during exercise. This works out to about 30 – 60 grams of carbohydrate per hour of exercise. You should start consuming carbohydrate after the first 60 – 90 minutes.
Carbohydrate is the only fuel your body needs during exercise therefore seek food and drink sources low in protein or fat. Popular sources include sport drinks, bars and gels.
Guidelines when choosing food to consume during exercise:
1. Look for carbohydrate foods that are low in fibre since it is too slow to digest during exercise.
2. For high intensity exercise, avoid fats and protein since they will also slow digestion.
3. Consider how convenient the food is to carry and eat while exercising.
4. Be sure to consume a mimum of 2 – 4 cups of fluid with any solid food you choose. Consuming a food without adequate fluid can cause stomach upset and indigestion.
5. Consume foods in small amounts over the hour rather than all at once.
6. Always try a food several times during training to be sure it works for you before trying it in a race.
Common foods used during exercise: bagel, banana, raisins, dried apricots, arrowroots, pretzels, graham crackers, fig bars, sport drink, gels, sport beans, shot blocks.