I jounal my intake on long rides pretty carefully and was shocked to discover how perpeteum and heed negatively impacted my ability to ride well. After a period, the stomach cramps and nausea when using hammer products made it clear that my body didn't think that it was food. The other products including ensure, spitz, etc weren't helpful after the first 4-5 hrs - it may be the dairy/soy/corn connection (maltodextrin is corn based). Doing v long rides really requires calorie supplementation that I just can't get from just eating hotdogs and granola bars along the way so I've did a lot of exploration to find a solution. I experimented w/ the other grain and non-grain based 'milks' (rice, almond, etc) with unenthusiastic results.
then I tried coconut milk and was quite startled w/ the effect.
I got hooked on the chocolate/mint (good for sour stomach). The quality of energy was immediate and really good. After 10 hrs it doesn't give me stomach issues(which was impossible w/ hammer products). Plain coconut milk (while it doesn't have as many calories) isn't sweet and is drinkable as plain water. This is SUCH a wonderful thing... consuming SWEET everything for 40 hours is just nasty after a while. For some reason, the milk out of the dairy case work better than the shelf-stable products. Coconut milk contains medium chain fatty acids which are metabolized as quickly as glucose. Muscles metabolize MCFAs directly (unlike ordinary lipids). My only hangup w/ MCFAs is that they are a saturated fat.... I don't know what's the health consequence of consuming gallons of the stuff over long periods of time. On the plus side, I've ridden my fastest 200k rides (3 times now) when I was using coconut milk. I can consume an equivalent number of calories using ensure, etc and find that I generally don't ride consistently well. This might be a placebo thing but I'm just happy to not be volcano vomitting on rides. Another up side is that it contains as much or more calcium as milk (as bone loss in endurance cyclists is an issue) and it contains electrolytes. A down side is that it contains virtually no protein. My ability to sustain v long rides requires at least some qood quality protein along the way.
Here's a very old review: (Chapter 5, Babayan)
http://books.google.com/books?hl=en&...q=mcfa&f=false
A nutritionist suggested that I must have the genetics to be a 'fat metabolizer' (I have no idea what THAT means since I store the stuff quite effectively
) and that's why MCFAs work well for me. She suggested that it might not be generally true for most folks. Let us know if it works for you!
On a side note -The one thing that endurance riding has made worse are my negative food sensitivities (I react in much the same way that you do and my data clearly show that wrong food choices on the ride effect my ability to ride well... if it gives me a headache/stomach ache chances are I'm not riding well on it). I started to work w/ the Paleo Diet (limits grains and dairy) and found that when I had to consume something inappropriate from a gas station on a ride, it was less likely to make me sick. Maybe some thought to your daily diet would be helpful.
On a second side note.... emember that you have a digestive system that is designed to process a wide spectrum of molecule types all at once. Focusing on a single solution (or a single source of calories) is limiting your system of its potential.
good luck with RAAM. We look forward to hearing about your preparation for the race!