Originally Posted by
GhostRider62
Me too.
After 3-5 days, the stomach is like a blast furnace. Something changes. Whatever I throw in, it goes poof. It demands something along the lines of 4 Egg Mcmuffins for breakfast and 2 Quarter Pounders with cheese, two apple pies, and a large shake for dinner. I can drink various carb solutions but that isn't practical on a long ride. 400 kcals/hr is 100 grams and let's say it is a 24 hour 400k. That would be over 5 pounds of sugars to carry. There are very good reasons we crave fats and proteins.
That's all due to the fact that you're riding at a relatively low intensity to do that sort of thing. I've seen riders with the worst digestive problems on the the first major climb of the day when they are still relatively fresh and going hard. Low blood flow in the intestinal wall is what I'd guess.
It's not going to take you 24 hours to ride a 400k at that level of burn, 800kJ/hour. It only took me 15 hours saddle time to ride a mountain 400 at 250 kcal/hour. I did it on probably 80+% carbs, still riding well at the end, no problems. I can't burn much fat in Z3. Now on a multi-day brevet, that's another story. Not much Z3, nope. No way could I have ridden another 400 the next day. I was toast. Fueling choices depend on what you're doing, which dictates pace which dictates optimal fueling.