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September 2, 2009

Ironman Nutrition Part 1

If I have come to know anything in the last few years it’s that you should never look into the sun with a pair of binoculars.

No that wasn’t it. It was that that… well. That is true though. Anyway.

Ironman raceday is only, and ONLY, about two things. Pacing, and nutrition. The pacing bit we practice and practice and practice beforehand, and the one thing athletes skimp on, due to budget constraints, lack of focus and general dumbassedness is that they don’t practice their nutrition before the actual raceday.

They then shove more calories in their bodies than they need, and WAAAAY more than they practised, on raceday, and expect it to work.

So, in a series that starts today, because if you look at this picture:

You have that many days left, as of today, 2nd September, to practise practise practise before the next likely Ironman you will do.

There are so many theories as to what you should do at Ironman with your nutrition. For me, there are a few golden rules that you should under no circumstance (your mother being held at gunpoint by Paul Wolff demanding you do these things included) even attempt:

1. Never try anything new on race day.
2. In fact, don’t try anything new on race week.
3. Do NOT, like I did at my first race, pile in a 3000 calorie breakfast.
4. Do NOT, like I did in my rookie race, wake up at 2am to eat. That would fall under heading 1 & 2, dumbass.
5. Do NOT sacrifice your training nutrition for the sake of a new set of gear. Better training nutrition far outweighs the advantage of a new race top. Spend your money on making you faster. Recovering better on big training days outweighs that new top, and the difference in cost is the same.

So in an effort to be correct from the start, lets start at the beginning. Your big rides and runs should be fueled according to the Ironman plan, in training. But how many calories should you consume during each hour? What is the plan?

The first rule is to keep your riding constant. Spurts in heart rate takes blood away from the gut, and that means your gut isnt processing your nutrition, its helping the muscles survive. So the first skill you need to learn as a potential Ironman, is to ride steady on the HR. Yes, it means going slow on the hills, but it means going fast on the flats too.

A good, steady Ironman ride (4-5 hours in training) can be worked as follows…

Bike calories can be worked out at a rate of 0.17 calories per minute per kilogram x 60 (minutes) x bodyweight of the athlete. So for me, at 75kg, its 765 calories per hour. This is quite a common theory on many of the sites on the world wide web.

At an Ironman race, I will go through 1 bottle of Whasp AminoCarb (150cals) and 2 gels (260 cals) per hour. I will also eat half a preferred bar of choice to add around 100 cals to make a total of around 500 calories per hour. That’s the max I can get in, and in training, I am generally a bit less, with consumption around 400 cals per hour.

So am I coming up short? I don’t think so. I have yet to have an energy bonk at an Ironman, and haven’t bonked on a ride in years. Sure. I`ve collapsed into what can only be described as a fetal position slumber but on all those days my nutrition was short.

That would mean my critical values are around 0.11 calories per minute per kilogram. i.e. 0.11 x 60 x 75 = 510 calories per hour.

We can’t talk about the run yet, because most of you can’t run like you bike i.e. the pacing thing. There is a fascinating set of articles about this at Endurance Corner but alot of it goes even over my head, so I am taking time to get to know my power outputs again.

So for the bike, lets assume your training values are about 20% below your race values, for now. So at the following weights, you need to be consuming, on the bike, in training, per hour:

55kg = 290 calories per hour
60kg = 317 calories per hour
65kg = 335 calories per hour
70kg = 369 calories per hour
75kg = 396 calories per hour
80kg = 422 calories per hour

20% lower than race intensity allows for enough margin in your non-ability to keep it consistent and at the right intensity in training. It also allows for a bit of weight loss but gives you the margin to not have to eat like a pig after the ride to make sure your weight loss is gradual and real.

So, first we practice on the bike eh… go check your nutrition and check what you are putting in. If you aren’t finishing your rides strong, it could very well be a lack of nutrition.

That’s it for part 1. We will come back in part 2 and discuss your energy pacing strategies for the bike section at Ironman and what you should realistically be aiming to run next year.

2 Comments on “Ironman Nutrition Part 1

Steve Blake
September 2, 2009 at 4:38 pm

Nice one – Quite an interesting post. I always knew that nutrition was important when training and of course when racing but I didn’t have an idea of how much I actually needed. Thanks dude!

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Ironman Nutrition | Ironman by 40!
October 4, 2009 at 11:58 am

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