Barf, barf, slosh, slosh, Oh how unfunny it is.
The simplest way to !!FAIL!! on STP, seems to be to have plenty or no food!
So, there you are, 150 miles from Seattle, starving, starting to get a bit weak and tired, so what do you do? Wow! Those burgers and fries at the "support" stand sure smell good! Look at the milkshake! Gotta have one! Gotta have one.... or not.
Been there, done that, have the !!FAIL!! to prove it!
As a newbie, I started out doing what I did as a kid: jump on the bike and ride.
I make sure I had some water to drink, but that was about it. I figured it would help with weight control and that was that.
What a clueless wonder I was!
I forgot/didn't remember/I was little, realize how short my bike rides were: I was proud that I rode the .2 of a mile to my friends house: that was a big deal! and riding to the mill 1/2 mile away? That usually involved a couple of stops.
Fast forward (entirely too fast, I think) to my "neat bike" I got in '98. I would ride that about 20 miles and it seemed to be a long ride, so I made sure to be back by then. I never got longer than 20 miles (or so) and it wasn't clear why.
Then, in Oregon, I road with a group, and, after about 25 miles I bonked: my legs turned to rubber and I could only ride at about 5-6 miles per hour! It was grim pushing myself to keep up and get home.
I quickly learned that this was "bonking": a person has burned up all the readily available fuel.
A person starts with 500-700 kcal's worth and it is usually replenished by converting fat. But those little fat cells are reluctance to "give to the cause" and demand lots and lots of oxygen.
Even young sprouts can get into trouble: ever see someone "time trial" or "hammer" for more than just a short time? Of course not. The kids know they're only go to hammer for about 1/2 hour before !bonk!.
But, what if you're one of the older set? And you want to ride 200 miles in 16 hours?
Ouch, that's a problem. Gotta eat something!
OK, so if no food doesn't work, then load'em up before you start!
Yeah, sure, eat a huge breakfast, see how it works for you. For me? Not so well.
The Stomach Curmudgeon
will get'ya! That's the body's crusty minion that is the guardian of the exit - nothing gets past before it is ready!
I tried having a decent breakfast before one Portland Century ride to give myself more energy for the 100 miles. It was 2 hours before I would start so I had eggs, bacon, milk, in significant quantities.
About 10 miles into the ride, around Molalla, I started fading: my stomach was very full, fuller than when I started (although I had been drinking), and I was getting that nauseous feeling. While I didn't barf, it was a close thing.
This was, of course, before I knew about MHR, etc.
I ended up dropping the hill on Sawtell Road by taking a beautiful cutoff, Wilhoit to Thomas Roads, not in the route) and only completed the shorten half of the ride.
The good news is that after being off the bike 2 hours, I was just fine!
At the REI station, 25 miles into STP, someone had left their breakfast on the ground. Didn't clean it up and it was pretty gross.
I bet you know that feeling....
Coming down the hill from Hawi, 70 miles into the 112 mile ride, the temperature was only about 90 but I was starting to feel dehydrated. Not a nice feeling since my stomach was, literally, sloshing with plenty of water! I had been drinking my liter/hour and should have been fine, but I wasn't.
So there I was, stomach full of water, sloshing, but it wasn't making it "in"! Bummer!
I went into the Kawaihae Historical center and rested and sipped water for the better part of an hour before I got back on the bike to ride the 35 miles to town. On the way back, I didn't drink any energy drink nor eat any energy gel: all I wanted was "water" which, fortunately, was well stocked from the stop in Kawaihae.
Being "hit on the head", I researched and found out about "osmotic ratio", or, as I call them: The Osmotic Police!!
I found the following to be very interesting discussion on how to !!FAIL!!. I note, it is only a half Ironman distance:
http://www.rice.edu/~jenky/sports/abd.pain.html
Another study looked at carbo loading in the days prior to exercise. One group ate the traditional pasta and rice diet, while another group ate less, but substituted the difference with a maltodextrin drink (supplement). Both groups had similar muscle glycogen concentrations (as determined by muscle biopsy) and treadmill times until exhaustion, but the supplement group had less GI complaints.
Minimize residue in the upper digestive tract - this may benefit some who suffer during a race. Athletes may accomplish this by supplementing with a high carbo beverage, and decreasing their intake of fiber and "heavy" foods the day before, and the morning of, a race. It is important that caloric needs not be compromised.
A final point to consider is that most athletes adapt and have less GI complaints as their training progresses. There certainly is no one right answer for everyone, but hopefully as you learn more and experiment with your diet and hydration, the symptoms will lessen.
Severe, progressive GI symptoms may be signs of a more serious problem and athletes are advised to consult their doctor.