10 hours is a long time to go without sitting down and enjoying a good meal – it’s even longer when you are propelling your body.
Fueling has a huge impact on your ability to soldier on after you hit a rough patch. Not only does it provide fuel for your muscles, it provides fuel for your brain. I find that my performance tends to suffer more because my brain is being starved for fuel then my body. I get grumpy and unhappy when I bonk, for me that’s an instant indication that I am short on fuel – and I need to rectify the situation ASAP – otherwise at the next tough physical challenge my body will complain, and my brain will capitulate. This is exactly what happened at Kona in 2007. I was cruising along pretty well, but because of some bad choices on the bike nutrition my stomach was shutdown and no sugar was headed to my head. When I turned the corner to run up Palini drive, my legs said “Brain – how are we going to get up this mofo?” Brain responded “I don’t know guys, that hill scares me.” So I walked up it – and ended up walking a big part of the last 15 miles.
Unfortunately there is no magic formula for nutrition. You can’t take your body weight and plug it into a formula and get a number of calories per hour. You can get a starting point, but the composition of those calories, the timing, and even the exact number all need to be tested through out your training.
I started out my Ironman Career on Cliff Bars, Gatorade, and water. It got me through a couple strong races, but I always ended up with a icky stomach. I moved on to Infinit – in concentrated bottles and water. I think the concept of infit is great, but I had issues with it locking up my stomach and always feeling a little on edge in terms of bonking on longer efforts – perhaps my chosen formula just needed tweaking. Currently I’m using water, salt tabs (thermolyte) and powergels. In all cases the calorie count is similar ~2,0000 calories. Ultimately it comes down to personal preference and what works for you. Don’t be afraid to try something new on a training ride – better to bonk in June 90 miles from home then at mile 90 on Race day.
Beyond that it is wise to be prepared for the unexpected – what if you can’t stomach X on race day? What if it’s really hot? Windy and you are on the bike longer? What if you are working your tested plan, and you feel yourself start to bonk?
I think it is a good idea to sit down and think about some of those questions and have an answer? What will you do if your fueling plan encounters road block X? Burn the plan into your brain and if something crops up on race day, stay rational, remember your Business Continuity Plan, and execute it. Don’t panic.