Athletic Nutrition, Carbohydrates and Glycemic Index:
Carbohydrates are the nutrients which can be most efficiently broken down to produce energy: preferred energy source in athlete nutrition.
▪ A big percentage of an athletic nutrition should be from complex carbohydrates as they tend to contain other nutrients such as proteins, minerals, vitamins and water, have a high nutrient density and are not linked to any diseases whereas high levels of sugar is linked to type 2 diabetes and dental problems.
▪ Complex carbohydrates are generally found in cereals, seeds, vegetables, beans, potatoes and whole grain seeds. Simple carbs are found in sugar, milk sugar, honey, fruit sugar and corn syrup.
▪ Carbs are transformed into smaller sugars that get used as energy, the rest is stored in muscles and liver as glycogen. Once the glycogen stores are filled up, any extra gets stored as fat.
▪ Sufficient carbohydrate consumption can stop protein from being used as an energy source. If protein is needed as an energy source, it will not be able to build and maintain tissues. And this also puts pressure on kidneys as they have to work harder to get rid of the byproducts of this protein breakdown.
▪ Glycogen is an easily accessible source of energy for exercise. To avoid running out of energy, begin the exercise with full glycogen stores, fill them up during and after the exercise then you will be ready for the next exercise.
Use of Glycemic Index in athletic nutrition may have some value when considering pre- and post- training meals. These are eaten according to whether they are rated as low, medium or high.
▪ It is suggested low to moderate ranked foods- pasta, porridge be consumed several hours prior to exercise due to their long slow release of glucose into the blood stream. While high glycemic index foods- corn flakes, honey, sports drinks, sweets should be consumed during or post exercise because they quickly release glucose into the blood stream which will be rapidly taken up into the muscles.
▪ Carbohydrates in the form of sugars are the body’s prime energy source. They are a ready source of energy that can fuel about 90 mins of continuous exercise, which represents an energy reserve of about 2000kcal within the body. Carbs are required by the body because it is the most effective means of producing energy. The GI therefore is a useful guide.
▪ For pre-exercise snacks, the food needs between one and four hours to be fully digested and supplying energy. Snacking on high GI foods before exercise can increase the blood sugar level to an extent that insulin is released which causes the glucose to be taken from the blood stream and stored. This may be detrimental as the glucose will be required by the working muscles.
▪ Therefore eating high GI foods for instant energy before a workout may have the reverse effect. During exercise this insulin response is dampened, so glucose will supply the cells with glucose from the blood. Isotonic sports drinks are therefore a beneficial way of sustaining endurance performance as they are quickly absorbed and supply the cells with glucose for energy.
Please see Athletic Nutrition article for more information.