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Ironman Nutrition Essentials

  • By Lance Watson
  • Published July 16, 2012

Practising your nutrition is just as important as your physical training. You have many good opportunities to do so in this program on the long rides and runs. Write down your plan and analyse the contents for calories, fluids and sodium levels. Eat correctly on the bike and you’ll set yourself up for a good marathon. If you plan to race with the nutrition products on the course, train with them too.

1. For the first 15-minutes of the bike drink water and take in minimal calories, mainly in the form of sports drink. Let your body adjust to cycling, and allow your heart rate to drop. Eat when you have settled into a good cycling rhythm. Follow the plan you’ve trained with all season—don’t do anything new on race day.

2. From 15 minutes after the bike start to 30 minutes prior to the bike finish:

A) Eat 250–400 calories (carbohydrates) per hour. Large or muscular athletes tend to need more calories.
• Gel: 100–120 cal
• Bar: 200–240 cal
• Sport drink: 100 cal
B) Drink 1–1.5 litres of fluid per hour. This is two small bottles (600ml) to two large bottles (700ml) per hour, depending on climate and your perspiration rate. (Simple calculation: Weigh yourself pre- and post- ride during training. Every kilogramme lost is one small water bottle of fluid deficit, and this will negatively impact your marathon.)
C) A simple plan would be to take in a gel every 30 min (~200 cal per hour) and a bottle of sports drink per hour (100 cal per hour). Sip water with the gel. Depending
on the product, you will need to take up to 200ml of water per gel.
D) The products you use should also provide sodium: 500–750mg (for ex- ample, PowerBar Energy Gel has 200mg sodium; PowerBar Ironman Perform has 190mg sodium).
E) If the products on the course do not supply the recommended amount of electrolyte, consider additional supplements such as salt tabs.

3. Twenty to 30 minutes prior to the bike finish, reduce your calorie intake and only consume sports drink or water. This allows your stomach to empty while still allowing your gut to absorb the food and fluid ingested earlier on the bike. You will be able to start the run in a relatively comfort- able state. Once you start the run you can consume calories again according to your r4un nutrition plan.

4. Follow a similar plan for the run, but reduce calorie intake by approximately one-third. Keep up your sodium intake and hydration. Many athletes prefer gels or liquid calories over solids on the run.

You should note that your calorie intake and heart rate are inversely related. As you start to exercise, blood is di- verted from your stomach to your working muscles and skin to create sweat and help cool you. As your heart rate rises, you are less able to digest the calories you take in. Therefore your race-day nutrition plan is intimately bound to your racing heart rate. Make sure you show up to the race knowing your heart rate intensity zones and having practised eating at those heart rates! The most common mistake is to consume too much at a high heart rate. If your heart rate is up, adjust your calorie intake downward. Also, do what you’ve been doing in training—again, don’t try anything new on race day.

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