Troup wrote:
While marathoners need more body fat than most people assume. An individual with 4-6% BF, which is common in sprinters and bodybuilders will not be a good marathoner. Of course, a good marathoner won't be 20% BF either.
Nope. each lb. of fat contains 3600 Kcal. A 140 lb lean American male would have ~7 lbs of body fat if he was 5% body fat. Since you burn carbohydrates as well during a marathon-intensity effort, this person would have enough fat for several marathons.
Fat burns in a carbohydrate-flame, so it doesn't work like having a 25,000 Kcal gas tank on board, but that is how many Kcal are stored on that person as fat.
The two-hours worth of glycogen must have around 1500-1800 Kcal.
I don't know where this idea came from that sprinters are leaner than distance runners. The best sprinters are taking different drugs than the best distance runners, and they ARE drugs that burn body fat, but where do you get the idea that a marathoner needs more fat "on board"?
How would that jive with pro cyclists, who race in 5-8 hour events?