Originally Posted by boneshaker
I agree with you Alan. Certainly cyclists are more often dehydrated than hyper-hydrated, but if the poster has to stop frequently to pee they are probably not dehydrated. Bonking because of a lack of water is not fun.
As far as food is concerned, try some different things on ~50 ish mile rides. At that distance you probably don't NEED food to have enough energy, but you will certainly be able to feel how your body reacts to the calories. It's how I learned about fig bars which are great for me. If I'm in calorie debt bad enough I can feel them almost immediately. People react differently to different foods though so experiment around a bit. Organized rides are good for this because they will feed you at the stops. A word of warning... foods with a lot of fiber can turn out badly. Stay away from anything that takes your body effort to digest. Digestion takes blood and when your body is using the blood to power your muscles it doesn't need to fight with your stomach. A few years ago at the STP I saw some poor guy turning inside out because he ate a lot of pineapple and his body couldn't handle it. I'm sure it tasted great at the stops, but 200 mile days are not the place to introduce new foods.
Speaking of long rides, I missed a ride with friends out to Larch Mtn this weekend and I'm bummed about it. That's one of my favorite rides as well...
Being cold can cause your body to want to dump liquid too. Figuring out the balance; how much to wear, how much to drink, how much to eat, is critical to smooth, enjoyable riding. As you've noted though, your body has the systems that will let you know what needs be done to get things balanced out right.
I haven't read studies, but my impression is that the bonk isn't caused by lack of water...dehydration...but by lack of nutrition. Sugar for one, but also...I guess it's carbs. That's why fig bars work well. They're mostly fruit with a little baked cookie dough. I used to use them too. Lately, I've just been carrying dried figs, but that's for the short rides I've been doing.
Just once did I do STP, in one day. Wasn't one of the really speedy riders. At the pit stops, I stopped, had part of a muffin, and some other things. No pigging out. Letting myself feel very full when riding, is a 'no-go'. Eating a little bit, to the point of 'feeling right', is the objective (depending on the energy expended, that can be quite a bit of food though.). Same with water.
I guess some guys just pour the water in as they ride. Not me though. Water just sitting there, pushing my stomach out, never struck me as doing much good. When my mouth gets dry, I drink. Simple.