How to Fuel During a Half Ironman?

Nutrition during a Half Ironman (1.9 km swim, 90 km bike, 21.1 km run) has two main goals: maintain a steady energy supply and prevent dehydration, while minimizing the risk of gastrointestinal discomfort.

Before the Start

3 to 4 hours before the race:

Eat a meal that is high in carbohydrates, moderate in protein, and low in fat and fiber.

Examples:

  • Oatmeal with a banana and honey
  • White rice
  • Or, better a Gatosport cake

30 to 60 minutes before the start:

Consume approximately 20–30 g of carbohydrates, for example:

  • An applesauce pouch
  • A banana
  • An Näak Energy Gel, followed by a few sips of water

During the Race

Swim

No food intake during the swim.

Bike (The Key Time to Fuel)

The bike leg is the ideal opportunity to consume most of your calories.

Hourly Targets

  • 60–90 g of carbohydrates
  • 500–750 ml of fluids
  • 400–800 mg of sodium (depending on temperature and sweat rate)

Example Using Näak and Overstim.s Products

Each hour, you could consume:

This provides a total of 80–90 g of carbohydrates per hour.

If you prefer solid food, you can alternate with:

  • a Näak Ultra Energy™ Bar during the first half of the bike leg, before switching mainly to purees and gels as the intensity increases.

Aim to eat or drink something every 15 to 20 minutes rather than consuming large amounts at once.

Run

Digestion often becomes more difficult during the run, so easily digestible products are generally the best option.

Hourly Targets

  • 30–60 g of carbohydrates per hour (up to 90 g/h if your gut is trained)
  • Drink regularly at every aid station.

Example

Every 30 to 40 minutes:

At each aid station:

  • Take a few sips of water.
  • Drink an isotonic sports drink if one is available.

What to Avoid

  • Never try new nutrition products on race day.
  • Don’t wait until you’re hungry or thirsty to eat or drink.
  • Avoid consuming large amounts of food at once.
  • Don’t rely solely on water for several hours, especially in hot weather, as this may lead to inadequate sodium intake.

During Training

Your digestive system can—and should—be trained, just like your muscles.

Use your long training sessions to:

  • Test the Näak and Overstim.s products you plan to use on race day.
  • Gradually train your body to tolerate 60–90 g of carbohydrates per hour.
  • Practice the exact nutrition schedule you intend to follow during the race.

A nutrition strategy that has been thoroughly tested in training is just as important as your equipment. On race day, the goal is simple: don’t improvise.

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