With big calendar races like Quest Glendalough & Shore 2 Summit coming this weekend, the queries have started to filter through again. One of the more common questions we receive is on “Carb Loading” and do I need to carb load and if so how much? So before I answer that, lets see why we need Carbs at all…
Why we need Carbs?
Carbohydrates are sugars and starches that fuel our bodies, much like petrol fuels your car. Each gram of carb contains 4 calories worth of fuel. The human body stores this fuel as glycogen in both our muscles and liver. These glycogen reserves are relied upon to stabilize blood sugars and allow optimal muscle function. Runners who can balance out 45-65% carbs per meal will store up to 2 carbs per pound of muscle tissue and an additional 100-125 grams within the liver. This amount will keep a runner going for up to 2 hours at a moderate intensity, make the consumption of additional carbs necessary for races lasting longer in an effort to avoid muscle depletion, consequent dizziness (aka Boking) and profound muscle fatigue (aka the wall).
In the week leading up to your race (if its over the 3 hour marker), you will need to start “carb loading”. You will need to consume 4-5 grams of easy to digest (low fibre) carbs per pound of lean body mass each day up to the 72 hour marker. Such easy to digest carbs might be bananas, plain bagels, white rice, potato, rice based cereals, sports drinks and energy bars. A single-day or 48-hour carb-loading protocol may be effective for shorter races, especially if the athlete is training through the race meaning no reduction in training volume is being implemented pre-race.
Aim for about 100-150 grams of easy to digest carbs in the 2-3 hours leading up to the race, Be sure to about an hour digestion time for every 200-300 calories consumed. A sample pre-race meal to be consumed in the 2- 3 hours leading up to race start would be a plain bagel topped with a smear of peanut butter and honey plus 20-24 ounces of sports drink.
Aim for approximately 25-33% your body weight in grams each hour of racing beyond 45 mins. E.g. 180lb racer should look at consuming 45-60 grams of carbs each hour of racing. To maximize carb absorption into the muscles and extend your endurance, choose products whose ingredients list include multiple types of carbs. e.g. glucose/dextrose, sucrose, maltodextrin and fructose. These are commonly found in energy gels, energy bars, sports drinks and energy chews.
Aim for 50-100 grams of carb, preferably in liquid form to promote quicker re-hydration.