Diet a vital part of preparation for worlds DAEGU -- As Kenya asserted itself as the long distance running country at the 2011 World Championships in Daegu , what may surprise most is the sheer amount of food these athletes need in order achieve these feats . When running extreme distances , the human body consumes a massive amount of energy , which comes from the only rapidly available source , glycogen . “ It ’ s like a car that runs fast and far , you need a lot of gas to fuel the vehicle , of course the amount matters depending on the make of the car , ” Korea ’ s marathon manager Yoo Jae - suk told The Korea Herald . Aerobic athletes focused on endurance rely on the ready availability of glycogen , which is converted from carbohydrates , rather than fat . Fat is consumed at such a slow pace that when runners deplete their glycogen stores and begin to tap into fat for energy , runners suddenly find themselves unable to move . So in order for long distance runners to ensure that they will have a steady supply of glycogen for the race , the athletes undergo training drastically increasing their carbohydrate intake , or “ carb - loading . ” This is done by slowly increasing the amount of carbohydrates consumed in addition to their normal diet , according to the Australian Institute of Sport . For athletes like Korea ’ s Kim Seong - eun , who came in 28 th during the finals on the opening day of the Championships , and her teammates Lee Suk - jeong , Chung Yoon - hee and Park Jung - suk , they needed to eat some 5 , 000 calories before the big race . “ They definitely eat a lot of carbohydrates , but we don ’ t set how much they need to eat . Each individual athlete is different , ” said Yoo . The U . K . National Health Service recommends an average of 2 , 000 calories a day for an adult woman . Before undertaking what seems like a bread , pasta and , in Korea ’ s case , rice overdose , athletes begin the month prior by focusing on consuming iron and calcium along with the a normal diet , consisting of protein and vegetables . Some two to three weeks before the meet , runners will reduce their diet to around 80 percent of their normal amount . Some seven days before the race , athletes add bigger loads of vitamin C to their diet , and replace their carbohydrates with protein , called the depletion phase , according to the Australian government run research facility . “ A week before the start of the games they are eating anywhere from five to six servings of protein , ” said Yoo . A day before the big race , some athletes will consume up to 5 , 000 calories throughout the day , consuming 60 percent of the calories purely through carbohydrates . “ If you put it generally , the runners need some 5 , 000 calories , but of course some eat more or less . Marathon runners in particular need to eat well and they need to eat a lot , ” said Yoo . “ They eat much more compared to other athletes . ” That is why if marathon running is aerobic , then sprinting is purely anaerobic relying on strong bursts of energy rather that long stores . Simply said , sprinters focus more on weight management and achieving low body fat levels . Sprinters will work hard to maintain a trim profile , eating larger amounts on training days , but reducing intake during days off . By Robert Lee ( robert @ heraldm . com )