Fueling For 70.3

This is from a September 2012 Lava Magazine article written by Ben Greenfield.  There is no direct link to the article since Lava requires a digital subscription.

Completing my first 70.3 event this year, I spent a lot of time researching how to fuel during the race.  Sprint triathlons are fairly easy to stay properly fueled.  Olympic triathlons are very similar to sprint distance, the only difference is the frequency in which one fuels.  However, jumping from olympic to half-ironman (HIM), there is a big difference.   The first thing I learned was to front-load the calories by doing the majority of my fueling during the bike leg.

"Ultimately, if you've kept your calories topped off on the bike, you won't need to concentrate as much on fueling during the run, and your goal is to give yourself just enough hydration and sugar to get by so that you can concentrate on maintaining a high run intensity"

Ben does recommend a starting point for calorie consumption:  Women: 250-350 calories per hour on the bike, followed by 150-200 calories per hour on the run.  Men: 300-400 calories per hour on the bike and 200-250 calories per hour on the run.  Again, these are starting points that need to be perfected during training.  Since I weigh around 190 pounds, my consumption was higher than the recommended amount.  Not by much though.  Per my HIM race report:

"I had my GARMIN set to beep every 15 minutes to remind me to hydrate.  I had four water bottles on my bike: Two behind the seat and one on the seat tube.  These were filled with nutrition.  I had one bottle between the arms filled with water.  There was also a salt tab dispenser under that water bottle.  Every 15 minutes I’d drink, every 45 minutes I had a salt tab and a gel.  It worked perfectly.  Thank you GARMIN."

I felt my nutrition was perfect, except I did get very hungry on the bike.  I'll make an adjustment by adding a solid food to my bike fueling.  I did carry much of my fuel with me because I had no idea how my body was going to react to the fuel at the aid-stations (Ironman Perform).  Ben Greenfield agrees with my approach:

"I tell many athletes I coach to stick to their own fuel on the bike and then switch to aid station gels and Coke for the run.  You can get away with this fuel switch because you will be consuming far fewer calories during the half-marathon."

During the run, I did not carry any fuel other than gels and salt-tabs.  I normally run with a fuel-belt, however there was an aid-station every mile, thus no need to bring the belt.   I lived off of Coke, Gu Chomps and pretzels.  I had no GI issues at all.

As stated earlier, the calorie recommendation is just a starting point.  However, Ben Greenfield does give a sample fueling strategy in the article:

1. 5-10 minutes pre-swim: 1 gel or 4-6 ounces of sports drink.


2. Coming out of T1: 1 gel every 20-30 minutes (or concentrated sports drink).  Break-up the monotony of gels and liquids with chewable fuel sources at the end of each hour (this is where I made my mistake).


3. During the bike ride:  Drink plain water when thirsty.  Continue fueling and do not go into T2 hungry (oops) or thirsty.


4. Coming out of T2: Eat 50-100 calories if you have not had any fuel in the past 15 minutes.


5. During run: 1 gel every 20-30 minutes or small sips of Coke at every aid-station.  Drink plain water when thirsty.


6. Final miles:  Intensity usually increases so limit fueling.  Otherwise you could run into GI issues.