The question posed was, "If you run or bike long distances, I'm hoping you can help answer a question my coworker has. (Or point us to a web link or something.) My boss and I got her to go paleo after reading Taubes' books. She training for a 120 mile bike race at high elevation (10,000 ft and above) and she's wondering how that's going to work into the paleo lifestyle. She usually loaded up on carbs before a big ride. Is that still what she should do now? She has several 50 mile rides planned before the big event, so she's willing to experiment with different things."
Great question! I am an endurance runner and have been eating paleo for a couple of years now. Nutrition while running was something I needed to tackle early on when I switched from the SAD to eating low carb, then to paleo. Traditional endurance "foods" never really sat well in my stomach (Gu, Power Bar, Hammer, etc), and I was making do with consuming granola bars and sometimes cliff bars which I digested better while running. Or, I would not eat at all (very bad idea).
Based on my experience with endurance events since switching to the paleo diet, I do not recommend the traditional 'carb load' the night before an event (or even long training run/ride). Including some healthy starchy carbs (potato, maybe polished white rice, etc) with your meal the night before is great to make sure your glycogen stores aren't depleted before you start the next day, but 'loading' (big traditional pasta dinners, or carb-only meals) seems unnecessary and likely harmful.
For races, my goal is to keep my glycogen stores from getting completely depleted, to consume enough salt, and to get enough fat, protein, and potassium to keep me going. Since I don't do the commercial endurance foods, I worked with Greg to come up with a good mix for me and my needs. I shoot for about 250-300 calories per hour. The Perkins Goo recipe (per hour) is: 1TB almond butter, 10 grams' worth of a scoop of protein powder, 1TB glucose syrup (Karo), some salt, and some water to make it your preferred texture. Mixing the banana in is good (flavor and a little fructose for liver stores), but on a bike it may be easier to drink the goo and eat about 1/2 banana. When I premixed my goo for a 12 hour event this past weekend, I mixed a big batch based on what I needed for 12 hours, then added enough water so that I could easily judge how much I needed to consume each hour, which ended up being 1/3 cup.
A really big lesson I learned firsthand at an endurance event back in March was how important to stay ahead of dehydration and glycogen depletion curves on longer events (you can get away with all sorts of goofiness if it is less than 2-3 hours, but you can seriously hurt yourself if you aren't careful in events longer than 4-5). At that event, I just wasn't feeling good so I was skipping the goo and not drinking enough water; and half-way through the race I was dehydrated and couldn't catch up. I had to stop running completely after only 9 hours because of severe leg pain (diffuse, on every footfall, even when walking). In contrast, this past Saturday I ran another 12 hour trail run (w/ total of 54 miles) diligently drinking enough water and eating my goo every hour, and I didn't have any troubles.
The Paleo Diet for Athletes is a great resource for endurance athletes (though I am more limiting in my carb intake than is recommended in the book). I used it to better understand my needs in endurance events, and the dangers of not meeting those needs, to design a lot of the above -- the rest was basically trying things out to see what would let me perform my best.