Originally Posted by
Heathpack
Fabulous post @
Machka.
In my training notes, I have written down that your average cyclist has 1600 cal of stored glycogen. My guess was that was based on a 175 pound male and scaling that down for me at 135 pounds, I have used the working assumption that I have about 1200 cal of stored glycogen.
I also am not a hammer type rider, I ride long distances at a moderate effort for the most part and am rarely out of breath on a ride. I think I burn about 400 cal/hr, given my size and riding effort.
My third factor that I consider is that I think I am very well conditioned to my typical ride length/effort.
So considering that I would usually eat about 200 carb cal before I head out for a typical 4hr ride, I figure I have 3-4 hours of stored glycogen, so starting eating at the 2hr mark should leave me a good safety margin. Last weekend, I knew I was doing a tougher/longer ride and ate about 400 carb calories prior to the ride and 1000 carb calories on the bike. I didn't really think this through beforehand, but now I can see that I cut things a little close, by my own calculations (which admittedly are very approximate), I left myself at the end with only 100 carb calories or 15 min of riding. I was pretty tired at the end, which I thought related to the effort expended (maybe I was right) but maybe I was running out of calories too.
Thinking this through right now is a great exercise for me because I'm soon riding a century ride which will be tougher than my normal rides and I will probably ride it a little harder than usual. I think I will make point of eating a little more, I'll have to work out the math on it.
H
Agree with Machka. Very, very important to start eating at your maximum sustainable rate right from the start. I start eating after 15 minutes. To that end, I eat a 400 cal. carb/protein/no fat breakfast far enough in advance that I am hungry at the ride start. IME the first three hours are the most important for eating. Once you have your routine established it takes care of itself. You may not need to eat as much as the end of the ride approaches. I usually slow it down and ramp up the effort, but I've been doing it a long time and know what it should feel like. Many, if not most people make the mistake of not eating at the beginning and then ramping it up toward the end, when it's much too late. Then they say, "Oh, but I ate plenty." Not.
When reasonably conditioned people get overtired on a century, it's always lack of food. If you've been eating enough and staying under LT, you shouldn't get exhausted. Hurt, yes. Pain, yes. Tired, yes. But your legs should be there for you when you need them. I've had some of my strongest efforts at the ends of very long, hard rides when a hour ago I thought I was going to die from the heat and effort. I was able to back off just enough to get enough calories into my legs for one more hour's effort. It's all about the calories. The first American finisher in last year's RAAM says it's an eating contest rather than a normal bike race.
You really don't have to work out the math. You need to get the feel for what your stomach will tolerate. The more you can eat, the better, because then the more watts you can put out without running out of glycogen. The nice thing about shorter LD rides like centuries is that there's a known end. On ultras, one needs to have the glycogen last almost forever, and develop a strategy to do that, as Machka points out.
If you overeat, you'll know it because you'll get "sloshy stomach." The cure for that is to stop eating, back off the effort slightly, take 2 Endurolytes and up your plain water consumption until your stomach empties. That happens when the concentration of nutrients in the stomach gets too high: it won't go across the wall fast enough until it gets diluted. If you don't fix it, you'll bonk. This can happen either from eating too much or not drinking enough. So there's that problem to consider, too. Personal experience is the only way to sort this. I do best on liquid Hammer-style nutrition.
Trying to stay focused on long rides, I eat every 15 minutes and stand for a minute or less every 10 minutes. Checking my status this frequently keeps me in the game.
-DD