Do you often experience gastrointestinal problems during training or competition?

Gastro-intestinal (GI) problems are very common among athletes, especially in endurance sports. Symptoms may include upper GI complaints (belching, vomiting, bloating, stomach cramps, nausea) and lower GI complaints (cramping, flatulence, diarrhoea). These symptoms could impair performance during competition.

The main causes of exercise-related GI problems are:

– Physiological: reduced blood in the intestinal tract, stress and anxiety
– Mechanical: for example bouncing effect of running
– Nutritional: high fibre, fat, protein, fructose or lactose intake; dehydration; hyperosmolar beverages, like fruit juices and soft drinks

Here are some nutritional recommendations to prevent GI problems:

1) 24 to 48 hours before and during exercise, avoid:

– high fibre foods. Choose refined cereal products (white bread, white rice and white pasta) instead of whole grain cereal products. Choose low-fibre fruits and vegetables, such as canned fruits, fruit compote, ripe bananas, grapes, well-cooked vegetables without seeds or skins, carrots, zucchini, tomatoes.
– high fat foods and excess of protein
– dairy products that contain lactose, if you are prone to GI problems. Opt for lactose-free milk or soy drink.
– dehydration, because it can exacerbate the symptoms. Start your competition well hydrated but neither overhydrate.
– high fructose foods: fruit juices and fructose-glucose syrup found in processed sweets and drinks
– hyperosmolar beverages, such as fruit juices and soft drinks. Prefer isotonic beverages, like sports drinks.
– ice cold drinks. The optimal temperature for drinks is 10 to 15°C.
– heavily spiced foods

2) Try liquid meals, for example fruit smoothies with instant oats.

3) Train your gut. The gut is an adaptable organ and can be trained to increase gastric emptying:

– train with large volumes of fluid
– do some of your training sessions immediately after meal to accustom your gut
– train with high carbohydrate intake during exercise

The volumes should be progressively increased and the adaptation time takes a few weeks. This should of course only be done in prior consultation with your coach and tests should not be conducted during important training sessions or competitions!

4) Practise repeatedly your competition nutrition strategies during training sessions that match the intensity and duration of the competition event.

Clinical Sports Nutrition, Louise Burke & Vicki Deakin
Practical Sports Nutrition, Louise Burke