What do all of these situations have in common? They all require energy to be performed, and just like a car gas fuel to perform; your body needs fuel to perform all of these activities. The main nutrient that provides energy for our bodies, especially during physical activity, are carbohydrates. In fact, our brains almost exclusively use carbohydrates for energy (yes – thinking does require energy). Carbohydrates are a group of compounds including sugars, starches and fibres (our bodies don’t use fibre for energy, but they are still important for good health).
Carbohydrate recommendations for athletes range from 6-10 grams per kilogram (2.7-4.5 g/lb) body weight per day, depending on daily energy expenditure, type of sport, sex, and environmental conditions. Youth athletes may need even more to support energy needs for growth.
|Sugars||Table sugar, honey, maple syrup||~ 5 grams per teaspoon|
|Fruit and fruit juices||~ 15 grams per ½ cup|
|Starches||Root vegetables such as potatoes, yams and squash||~ 25 grams per ½ cup|
|Bread||~ 25 grams per slice|
|Grains such as rice, oatmeal, barley, quinoa||15-20 grams per ½ cup|
|Pasta||~ 25 grams per ½ cup|
|Legumes||Kidney beans, chick peas, lentils||~ 22 grams per ½ cup|
|Dairy||Milk||12 grams per 1 cup|
When considering your carbohydrate intake for sport performance, there are two important factors to keep in mind – timing and type. Timing refers to pre-, during and post-exercise and type refers to the glycemic index of the carbohydrates. Glycemic index is a measure of how quickly a carbohydrate containing food raises blood sugar levels after consumption. High glycemic foods raise blood sugar levels quickly and include foods like most fruit, sugars and processed grains like white bread and white rice. Low glycemic foods raise blood sugar levels at a slower rate and include high fibre carbohydrates such as vegetables, legumes and some whole grains. Medium glycemic foods are somewhere in the middle and include whole grain bread and pasta, starchy vegetables and some fruit.
Immediately before exercise, focus on medium to high glycemic carbohydrates, which are digested more quickly and will help to top up your energy stores.
During exercise, focus on water for the first 30-60 minutes of activity, and add high glycemic carbohydrates, such as those found in sport beverages and gels, for activities lasting longer than 30-60 minutes.
Immediately after exercise is the prime refuelling time. Your muscles essentially act as a sponge to soak up nutrients in your blood to help repair tissues and replenish your glycogen stores for your next activity. Within the first 60 minutes after activity, focus on high to medium glycemic carbohydrates.
The remainder of the day consume medium to low glycemic carbohydrates at meals and snacks. Make sure to balance these meals with proteins and healthy fats as well.
Though carbohydrates are our bodies’ main source of energy, we also need to consume B vitamins to help our bodies make use of the carbohydrates that we eat. The B vitamins include riboflavin, thiamin, niacin, folate, B6 and B12 and are cofactors in the enzymes that convert carbohydrates to energy. Good sources of B vitamins include fortified and whole grains (particularly the germ of grains), spinach, dairy products like milk and yogurt, mushrooms and meat products.
Here is an example of typical day for a typical 13 year old, 100 lb athlete.
Canadian Diabetes Association. The Glycemic Index. [Cited September 24, 2013]
Dietitians of Canada. B-vitamins. [Cited September 24, 2013]
Dietitians of Canada. Position Pater on Nutrition and Athletic Performance. [Cited September 24, 2013]
Holway FE, Spriet LL. Sport-specific nutrition: Practical strategies for team sports. Journal of Sports Sciences. 2011;29(sup1):S115-S125.
Montfort-Steiger V, Williams CA. Carbohydrate intake considerations for young athletes. J Sports Sci Med. 2007;6:343-352.