Determine Your Century Nutrition Plan

The Ironman bike course Joe will be racing has a net elevation gain of 1,000 feet. Joe's goal cycling speed, as practiced during training, is 19 mph, which yields an energy coefficient of 0.0811 calories/lb/minute, and places him at the bike finish in 5.89 hours.

Step one: Joe's hourly cycling expenditure
0.0811 x 150 pounds x 60 minutes = 730 calories

Step two: Joe's total cycling expenditure
730 calories x 5.89 hours = 4,303 calories

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Step three: Add appropriate calorie expenditure based on course profile
(For every 100 feet of elevation gained, Joe adds 22 calories to his total expenditure)
1,000 feet gained / 100 feet) x 22 = 220 calories
220 calories + 4,303 calories =4,523 calories

Step four: Joe's total calorie replacement goal during Ironman bike leg
Minimum: 0.3 x 4,523 calories = 1,357 calories
Maximum: 0.5 x 4,523 calories = 2,262 calories

Step five:Joe's hourly replacement goal during Ironman bike leg
Minimum: 1,357 calories / 5.89 hours = 230 calories
Maximum: 2,262 calories / 5.89 hours = 384 calories

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Step six: How Joe will replace these calories
Because Joe spent the first 90 minutes of his Ironman swimming, calorie replacement on the bike can start immediately on the bike. On training rides, water is the only nutrient needed during the first 90 to120 minutes.

We calculated Joe's calorie needs during the bike leg to average ~1,800 calories. In order to simplify, Joe customized his sports drink with InfinIT Nutrition (

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Each serving of his sports drink contains 200 calories, 45 grams of carbohydrate, 5 grams protein, 375 mg sodium, 110 mg potassium, 30 mg magnesium and 15 mg of calcium. Joe's goal is to finish 1.5 servings (~300 calories) each hour during the bike leg.

Instead of carrying a lot of weight on his bike, he'll mix his formula into a concentrate and use the water at the aid stations, spaced in eight-mile increments, to meet his fluid needs. Joe's bike has two back-loading bottle holders and one on his stem.

On race day, he plans to carry two 24-ounce bottles, each containing 900 calories or 4.5 InfinIT servings on his bike, and one course-provided water bottle. He'll take shots of his formula every 10 minutes along with water so he'll consume eight ounces of his concentrate and 24 ounces of water each hour.

More: 8 Tips to Lose Weight From Cycling

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Kim Mueller, M.S., R.D., is a competitive endurance athlete who provides nutrition counseling and customized meal planning to athletes worldwide. If you'd like help figuring out how to correctly replenish your cycling calories during your next event, contact Kim at For more information,

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