Hey Jeff, I have a couple questions regarding nutrition for a half ironman that I have coming up. This is my first half iron, and I feel overall pretty good about my level of training. The other day however, I went out for a 56 mile ride and bonked pretty bad around mile 40. I purposely went out in the heat trying to mimic conditions for the race but am concerned that I don’t have my nutrition right as far as before and during race eating/drinking.
Is there any specific rule that you follow? I took 3 sports gels and use powder in my bottles. I usually take some sort of bar/chomps but didn’t for this ride. I usually just have a protein bar/piece of fruit before my workouts.
Andrew, thanks for your email. Generally speaking, we need to take in around 4 calories a minute, or 240 calories an hour, when we engage in endurance work of 90 minutes or more. This is in addition to our stored glycogen. Gels are about 100 calories each, but I find that I can’t tolerate more than about one an hour, so I usually take in what I can and run a calorie deficit.
On the bike things are a little looser because digestion is easier (less stress on your body because less of it is in motion; you’re sitting, after all). I basically aim to consume as much as I can comfortably absorb while cycling, starting out with about 300 calories in the morning (you don’t want too much stomach content, or you can get side stitches). I also aim to take in electrolytes; usually I alternate nutrition and electrolytes every half hour.
What will be best for you is to find what works for you, as you’ve been planning. See what you can absorb and feel comfortable eating, and work your plan around that. Some people have very specific tolerances, others are real omnivores. The key is to just know all this before your race.