One major contributor to fatigue is dehydration and carbohydrate diminution. Whereas the major cause of low performance in endurance races lasting more than 30 minutes are gastrointestinal problems, hyperthermia, and hyponatremia, which are as dangerous as they sound.
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However, the good news is it can easily be managed with the right nutritional plan that talks not only about what to eat but also how and when to eat to maximize the benefit of workout recovery and race-day performance. This is especially important for the Ironman debutants – because let’s face it, the experienced triathletes have the edge over you in terms of their performance and wellbeing management. They have a detailed understanding of Ironman race-day nutrition. The good thing is, you can easily master it too; let’s get started with the nutritional plan.
Important Factors to Create Your Nutrition Plan
Carbohydrate consumption per hour – As per the research, 60-90g per hour is the optimum limit. However, it is important to understand that each triathlete has a different level of tolerance. So, if you are new at it, 45g per hour is a good place to start experimenting. Ideally, you’ll be able to consume more when you are on the run than on the bike. So, analyze how your body is responding to the carb ingestion and increase the consumption to 60g/hr. However, if you feel you need to go higher than this, you should add glucose/maltodextrin and fructose for better absorption.
Understanding the calorie requirement – The ideal range can be 4-5 calories (kcal) per kg per hour on the bike. Out of which, 80-90% will comprise carbohydrates, including gels and sports drinks, and the rest should be proteins and fats. Triathletes usually crave solid savory food. Stock up on energy bars, pretzels, rice cakes, nuts, or mini-sandwiches for your triathlon race-day nutrition. Just be cautious not to overdo to save yourself from GI distress.
Know your history of gastrointestinal (GI) problems – Research highlights that if you have GI issues occasionally or in everyday life, chances are you may experience them in the race too. Constipation and irritable bowel syndrome (IBS) are two examples of functional GI problems where the gastrointestinal (GI) tract looks normal but doesn’t work as it should. Taking measures to combat these issues is vital. You can try probiotics or glutamine to strengthen your digestive system apart from professional medical care.
Learn about your race pace – Your race pace will determine the digestion and absorption rate of carbohydrate and thus will define the quantity of carbohydrate intake too. Remember, longer race time means low carbohydrate requirements. That’s because your body pumps more blood toward your active muscles to supply them the required dose of oxygen, leaving less blood than normal to aid the digestion process.
Sweat-Rate – If you sweat too much or you’re competing in hot conditions, you need to increase your intake of electrolytes, especially sodium. You can add electrolyte tablets or drops to fluid bottles or consume them in the form of sports drinks, gels, or solid food.
Other factors to consider:
Plan how you’ll be carrying your nutrition
You can opt for the bottle cage, bento box, bottle mounted on aero bars, deep pockets or slots in your trisuit, fuel-belt, gel flask, or multi-bottle fuel belt. Plan in advance to keep unwanted worries at bay.
Learn about the aid station and track course
This will help you to understand how much nutrition you’ll have to carry. Inquire more about the spots where you can refill and the kind of nutrition that will be available at the aid stations like gels, energy bars, or bananas.
Prepare your triathlon bag and add spare nutrition products
This will help you in case you lose the nutrition you’re carrying, or you underestimated your nutrition needs for your Ironman triathlon. Meal Plan for Before, During, and After Race.
Meal Plan for Before, During, and After Race

BREAKFAST: 3 – 4 HOURS BEFORE THE RACE
A triathlete needs carbohydrates along with essential vitamins, minerals, proteins, and fats. The diet should be carbohydrate-rich, low in fiber and fats, and easily digestible. Here are a few options:
- Wholegrain toast or bagel with orange juice.
- Brown bread with honey or jam
- Oats or granola with skim milk
- Oatmeal topped with banana and strawberries
- Strawberry, banana & oat smoothie
Reminder: Don’t forget to stay hydrated! Drink flavored or plain water or fruit juice.
SNACK: 30 MIN – 1 HOUR BEFORE THE RACE
This is optional. Take it only if you feel like and only if you’ve tried it during your training period. You can go for a starchy snack; your options can be:
- Crispbread
- A fistful of dried fruits
- Saltine crackers
- Banana and oatmeal cookies
- Rice cake
- Banana
- Granola bar
Additionally, you can always go for a few sips of water.
Triathletes often wonder what to eat during the triathlon. They are also clueless about how and when they should eat. So, when you’ve completed more than 45 minutes to 1 hour of racing, you need to refuel your system to maintain and upgrade your performance.
Remember, these eating patterns should be well-rehearsed until your body adapts and responds positively to it. Your safest and most convenient bet is to go for sports drinks or light snacks; here are more things you can pack:
- Isotonic drinks containing carbs
- Banana and oatmeal cookies
- Sports gels
- Gummies
Remember to keep drinking water in small sips frequently. Do not wait for the thirst to kick in because, by the time you feel thirsty, your body will already be dehydrated. A dehydration level of only 3% can cause noticeable energy-drop, and we definitely don’t want that.
What to Eat After the Triathlon?
You will either collapse in exhaustion or hop around with your new shiny medal; whatever be the case, do not stop sipping fluid. Grab isotonic sports drinks to replace the loss of fluid, electrolytes, and carbohydrates in your body. You can also have a banana for the immediate supply of carbohydrate and potassium in your body to prevent muscle cramps.
Remember to eat in the right order: Liquids, then purees and then solid food.
Here are your post-race snacking options:
- Recovery bars
- Milkshakes, smoothies made with milk or yogurt
- Chicken or tuna sandwiches
- Cereal and milk
- Fruit juices or whey protein drinks
- Sports drinks (hypertonic)
- Low-fat yogurt with banana
- Corn flakes with skim milk and honey
- Oatmeal or pancakes
- Pasta, rice, or potatoes with meat, veggies, or lean fish
There’s no such thing as a ‘one size fits all’ nutrition plan for Ironman triathlons. Each athlete is unique and has different body requirements. It is important to understand how your body responds to different types of nutrition and the impact it has on the performance level. Once you understand what suits you, stick to your triathlon nutrition plan. Don’t forget to stop all your food experiments one-two weeks before the race. Do not, I repeat, do not try new drinks, sports gel or food on the race day.