Article on GI issues - Techniques to Keep Your Gut From Ending Your Race Early

Bambaata

Might be of interest to those going long. Im sure most are on top of this but still worth the read to reiterate the importance of testing nutrition in training. Its more geared towards Ultra running and possibly IM but it still rings true for short distances too. 1 thing i did do this year before my HIM was test, retest and test nutrition some more and luckily i didn't have any issues in my HIM race. Amazes me to hear of people using the course aid stations without actually having used what will be provided in training!

http://trainright.com/gut-check-techniques-to-keep-your-gut-from-ending-your-race-early/

zico10

90 % of things I would have known already, but it is an interesting article and as further reiteration of just how important nutrition is, it's worth the read.
The point that your stomach is an organ that needs to be trained, just like your heart and lungs, is worth bearing in mind. It's going to have a hard job digesting all the extra calories you force into yourself on race-day, if your stomach hasn't been used to it in training.
Likewise your digestive system is a system that needs to be trained, the same you train your respiratory and circulatory systems.
I agree with the last point you make yourself about approaching a race not having tested out the products on offer at the aid stations. However I think a lot of people are too quick to say they react badly to certain products, while failing to look at other factors that might have impacted on their performance. Factors such as dehydration, what you had for breakfast, how close you ate to the race, how much surplus energy you're trying to take on board, etc, are often overlooked and people are too quick to jump to the conclusion that they can't drink Powerade, etc.
It might be an overly simplistic way of looking at things, but if you sit down to watch a movie for 7 nights in a row, drinking 7 different sports drinks or eating 7 different sports bars, it's highly unlikely you're going to be feeling any different at the end of each night.
I'm only speaking from the point of view of ironman, I'll leave it someone else to speak for ultra runners. But unless you have your own huge support crew, that the race organisers allow stand at strategic points throughout the course, then I don't think you can afford to be that fussy in what you consume. I've heard stories of people planning to mix their preferred sports drink with water they pick up at aid stations, having a super concentrated sports drink mixture in one bottle, for dilution with water they again pick up at the aid stations and some other nutrition strategies that leave me scratching my head.