Big Unit Ironman Fueling

It’s important to find an ironman fueling plan that is effective over the length of your race, at specific efforts and that fits your body composition.

Until I had my protocol nailed down I practiced it in training on my longest days. I wanted my plan to be relatively simple so that it was highly repeatable. It also had to have a flavor I could drink (and assimilate) for hours. Remember, if you premix fuel it will be hot on the back half of your ride. Be ready for that and drink it anyway! As well, no plan is a good plan if your heart rate gets too high or you begin to get dehydrated. Your stomach will shut down, you’ll get nauseous will occur and your performance will begin to degrade before you are even thirsty. When I was racing I went all liquid calories on the bike (plus plain water) and all liquids on the run with an occasional GU.

When you consider your race fueling strategy, your overall plan should include a timely breakfast that is early enough to get out of the way by swim start, a bike and run protocol and correct efforts. If you do not practice all of those variables together you have never practiced “your” plan. Some smaller athletes eat/drink half as much as I did when I raced at 190lbs. Just find what works.

Once you have a lock-solid-guaranteed plan for your race you can train on less calories than your race protocol. You can go real long while fueling lean and act like a camel if you want to — but get a race plan.

I train with Infinit Nutrition on a daily basis. I love the taste and it’s a great product. In my ironmans I used Carbo Pro because to get enough calories I had to avoid the sweetness of some products when mixed rich. Carbo Pro is essentially tasteless so it can be flavored any way an athlete likes. Avoid too sweet when the temperature is high. There are no electrolytes in Carbo Pro so you need to build that into your protocol.

Here was my plan:

  • Breakfast at 3 a.m. for a 7 a.m. swim start (about 1200 calories of eggs, oatmeal, potatoes).
  • All drinks pre-mixed the night before and refrigerated until race morning: four bottles sized 22-24oz.
  • Each bottle gets seven scoops of Carbo Pro (700cal) and one half-scoop chocolate Interphase Protein (50cal). Interphase Protein is also made by SportsQuestDirect.
  • The four pre-mixed bottles make a total of 3000 calories for about a 5.5-hour bike split (about 550cal/hr) and a 14:1 mix (carbohydrate to protein).
  • On the bike I grabbed a bottle of fresh water at every aid station as I entered; drank it and tossed it as I left. That is a bottle about every 30 minutes. I tried to drink a minimum of 24oz of plain water for each 22-24oz bottle of Carbo Pro mix that lasted about 75-80 minutes. In hot races I often had quite a bit more plain water. Aid stations typically hand out 12oz bottles so I would need one or most of one at every aid station. Later in the race when I had a cage open up after finishing a Carbo Pro bottle I might carry the water with me and sip a bit if I started feeling full or wanted to pour it over my head.
  • In T2 I had a pre-mixed bottle with four scoops Carbo Pro (400cal) and I carried that the first three miles of the run. My goal was to finish it. Sometimes I did and sometimes I tossed it at mile 3. It was a chance to get in more fluids and calories if needed and reminded me to run the first three miles 20-30 seconds under my eventual goal pace for the first 5k. I’d give up that 90 seconds to let blood shift, get control and be smart. I had another 400cal bottle in run special needs. Sometimes I drank them and sometimes I never even took them out. I took a cup of Gatorade and a cup of water at all 26 aid stations. Occasionally a GU.
  • I made sure to take about 1100mg sodium (three Succeed Caps) per hour starting before the swim and on the bike and through the run.

Once you have a plan that works for you (including efforts) it can be tweaked depending on the weather but you will never have to look back.


Kevin Purcell, D.C., works with long course triathletes; from elite to those new to endurance sport. Coach KP has guided dozens of athletes to qualification to the Ironman World Championships in Kona, including over 15 IM age group championships. Dr. Purcell is certified in Active Release Technique (ART) and has completed a medical rotation at the Olympic Training Center in Chula Vista. Coach KP retired from competition in 2006.

Categories: Nutrition

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