If you've ever hit the wall during a triathlon, then you are painfully aware of the importance of a well thought out race day nutrition plan. Unfortunately you won't find one single, perfect approach; there's just what works for you that day in that particular race. So, where do you start? How do you create a plan that's consistent yet leaves room for last-minute changes? Here's my method.
Inconsistency In Science
Suck it up: No matter how many calories you take in, your body can only absorb them so fast. Current recommendations are anywhere from 30 to 60 grams of carbohydrates per hour (/hr) or 120 to 240 calories/hr.
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If you want to get really technical, some studies show that because different sugars have different transport mechanisms in your body, you can absorb up to 90 grams/hour or 360 calories by using a variety of carbohydrate sources (sugars). These studies are not universally accepted, however. Hammer Nutrition, for example, believes these studies may not be valid under race conditions.
Balancing Act: More and more endurance formulas are upping their electrolyte amounts. Currently the American College of Sports Medicine (ACSM) recommends sodium intake at 500 to 700 mg/hour with some sports nutritionists putting it at 800mg/hr. or more. Again these guidelines are not universally accepted. The most vocal detractor is Dr. Tim Noakes, the running sage out of South Africa who believes that when you sweat you lose more water than sodium. Therefore the sodium concentration in your body actually increases. As such, he feels there's no need for sodium intake, only fluid and calories.
Applying the Science
Practice in trainig. Find out what amounts are right for you. Knowing that I'll absorb less than I take in, I shoot for 250 to 300 calories/hr. If you feel you need more, try to consume the higher calorie amounts in the first half of the bike leg when you're more hydrated and when your body can more easily take in calories.
Solid or Liquid?
Know that liquids are easier to digest and absorb. I know some athletes who can't make it without their PB&J sandwiches but I recommend finding a fluid that works too.
More: Fluid Absorption Q&A