Carbohydrates for Nutrition and Exercise

When consumed, complex carbohydrates break down into simpler monomers (ex. glucose, fructose and galactose) that are transported in the body via the bloodstream. Specifically, glucose supplies energy for the brain, nervous system and muscle metabolism. Fruits, vegetables and whole grains are excellent sources of complex carbohydrates and other nutrients.

In terms of fitness and exercise, carbohydrates are a major fuel source for ATP synthesis. Carbohydrates are particularly important for long endurance activities that span over an hour: Given the limited glycogen stored in our bodies, it is necessary to consume adequate carbohydrates prior, during, and immediately to these long distance events to avoid muscle protein breakdown.

Carbo-loading

There are various methods to carbo-loading, or to maximize glycogen stores before endurance competitions. The most effective, and safest, manner to do so is to maintain a well-balanced, high carbohydrate diet and boost carbohydrate consumption two or three days before competition. Bloating and heaviness are common side-effects of carbo-loading because of the high water content in carbohydrates.

Glycemic Index

A glycemic index value is attached to food and refers to the speed that glucose enters the bloodstream following a meal.

High glycemic index foods include potatoes, white bread, instant rice, watermelon and rice krispies. These foods prove a quick release of glucose and are an excellent fuel source right before, and during, an event.

Low glycemic index foods are optimal for everyday tasks and endurance activities that require a regular and slow release of energy. Some examples of are beans, lentils, pasta, pears, apples and nuts.

Fibre

Dietary fibre comes from the cellulose of plants. Fibre is largely undigested and abrades the walls of your intestine. In turn, mucus is secreted from your digestion tract that helps regulates bowel function. The Canada Health Guide recommends that you should include at least 25 g of fibre into your daily diet.

The following are good sources of fibre:

  • Whole grains such as whole wheat, brown rice, whole rye and barley
  • Wheat and oat bran
  • Vegetables and fruit
  • Legumes such as dried beans, peas and lentils