I just finished what was for me a pretty big 'endurance event'. No, it wasn't a race except perhaps against the limits of daylight so we had to keep a good pace going. Also since I was in the saddle for better than 8.5 hours I faced many of the challenges I've faced endurance races in the past. The biggest problem I've had in the past on endurance events tend to relate to nutrition. Eventually after riding for 6-8 hours solid I eventually wind up eating either too much or too little, sometimes I just lose my appetite altogether. This time around I tried something recommended to me by my cousin, a liquid calorie replacement called Carbo-Pro.

The big selling point to me on the product was the 'flavorless' aspect of it. Many energy drinks and supplements are sweet or have a chalky taste to me. Carbo Pro is a powder you mix with water or an sports drink and it's nearly flavorless but adds 300 calories or easy to digest and turn into fuel. On my ride I mixed it either with a little gatorade or drank it straight with water and it really did the job. As I said above, we were pedalling for 8.5-9 hours and on the ride for over 10 hours and about 80% of my calories came from carbo pro. By the end of the ride my legs were raging, but I never bonked and more important I felt charged up and ready to go... at least until I started pedaling

I haven't experimented with any competing products, so I'm not going to rave about how much better it is than anything else, but if you have nutrition issues on long events you might give this a shot or Hammer Nutrition's equivalent HEED. I have heard HEED is flavored and that didn't appeal to me though.