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A successful endurance performance is not determined solely by how fast you can go, but by how successful you are at delaying fatigue. For a smooth transition to half or full Ironman training, getting your sports nutrition right is paramount.
Fuel to burn
When exercise extends beyond 2 hours, muscles become depleted of glycogen, which ultimately leads to fatigue. To combat this, maximize your glycogen storage potential with a balanced daily diet (especially post-workout), and consume carbohydrates during long workouts. Since daily carbohydrate needs are dependent on workout intensity and volume, consume between 3–10 grams of carbohydrates per kilogram of body weight per day (a reduced carb intake reflects a lighter training load).
You may have heard of fasted workouts, to improve metabolic efficiency. This approach may enhance fat oxidation to spare glycogen (stored carbs) to offset early fatigue. However, building a tolerance for greater training volume or intensity with low energy availability can overstress your body. Adequate fueling allows you to complete high quality training sessions without compromising health.
Dehydration affects a lot of things you need to perform well—from your rate of perceived exertion to your risk of heat exhaustion. There is an ongoing debate over whether to drink to thirst or to schedule your sips to help avoid health risks such as hyponatremia. However, recognizing thirst sensations can be unreliable. If you don’t take in enough fluids on a daily basis or don’t properly rehydrate after workouts, you may be starting workouts slightly dehydrated.
By consuming well-formulated sport drinks and electrolyte beverages frequently during long training, you can improve performance and reduce the risk of exercise-induced dehydration.
When transitioning to long-course training, allow at least 4–6 weeks to train your gut. Introduce hypertonic (3–5 percent carb solution) sport nutrition drinks during longer workouts. Always work your way up in nutrition, but be mindful of workout intensity to avoid bonking.
It’s a challenge to coordinate the ideal racing intensity with proper hydration and fueling without causing GI distress. Practice your nutrition and pacing strategies to feel confident on race day.
Long Workout Fueling Guidelines
(90 minutes before a 2+ hour workout)
Consume 2–3 grams per kilogram of body weight low glycemic carbohydrates and ~5–15 grams protein or fat for the ideal long pre workout snack.
Hydrate with 16–20 ounces fluids
Consume at least 40–70 grams of carbohydrates per hour in a 5–7% carbohydrate solution. To determine the concentration of sports drink, divide the grams of carbs by 240 mL (8 ounces). For example, 60 grams carbs/28 ounces fluids (840 mL) = 7% solution.
Aim for at least 120–180mg sodium per 8 ounces of fluids. Example: A 28-ounce sports drink should include 420–630mg sodium.
Each hour, consume ~24–30 ounce fluid while cycling and at least 16 ounces per hour while running Take 2–4 gulps every 10–15 minutes. (1 gulp = ~1 ounce).
To simulate muscle protein synthesis, replenish glycogen, suppress muscle protein breakdown, to encourage satiety and to help meet daily protein needs (1.3–1.8 grams per kilogram of body weight), consume 15–25 grams of high quality protein with 1–1.2 grams of high glycemic carbs per kg body weight in the form of a recovery snack within 30–45 minutes post workout.
-High-quality protein options include meat, fish, eggs, dairy and organic soy.
-For the athlete on the go, consider whey or vegan protein powder (mixed with water or milk) and a piece of fruit for a convenient and portable recovery snack.
-Rehydrate with 16–20 ounce fluid for every 1 lb of weight loss during activity
-Continue to replenish, rehydrate and refuel every 2–3 hours post workout.