By the time you hit the run course in a half-Ironman, you will have been competing for well over three hours. It may have been over five hours since your first real meal of the day. You probably have done several two hour runs in training, so you know you are capable of the distance, but you have to prepare for the energy requirements of racing for over five hours in order to be ready to test your true mettle come race day. In Ironman, the numbers are greater: it might be over three hours since breakfast by the time you get to the start of the bike. When you are on the start line of your big race, you need to know that you are ready to complete the distance, but also that you have planned out your nutrition for the day so you can actually reach your potential.
The main energy source your body will use for racing long distance will come from the glycogen stored in your muscles. This glycogen is formed when the body breaks down carbohydrates into sugars for energy. Even with the best carbohydrate preparation, your body only has about enough stored glycogen for two hours. Without constantly replenishing carbohydrates, you will eventually run out and “hit the wall” or “bonk.” You will then use your fat stores as energy, a process that is much slower and which requires you to reduce your pace considerably. You must constantly ingest carbohydrates and fluids during the race in order to maintain a steady stream of sugar to your muscles and to handle the optimal pace of racing.
You should note that your caloric intake and heart rate are inversely related. As you start to exercise, blood is diverted from your stomach to your working muscles and skin in order to sweat and help cool you down. As your heart rate rises you are less able to digest the calories you ingest. The food will sit in your digestive system instead of being used, which causes discomfort and gastro-intestinal stress for athletes. Your race day nutrition plan is intimately bound to your racing heart rate. This infers that you must train and eat in heart rate zones that are similar to race day.
Fuelling properly on the bike means taking in (as much as possible) enough calories to balance your caloric deficit and constantly refilling depleted glycogen stores so there is something there for the run. Since it is easier for the body to digest calories while riding, eating on the bike is crucial. Once the run starts, you must try to maintain energy levels as you can’t make up for what was lost on the bike without severely compromising your run pace. The real trick to running off the bike is to be both bike fit and to eat well during the ride so you are set up to run well.
What to eat and how much to eat is a strategy that each athlete has to work out for themselves. You should work out your race day nutrition plan through your training. Every long training session should include a plan for nutrition and hydration, including how many calories, what specific foods and fluids to take, and when to take them. You will have to try out your plan many times in training in order to figure out what works for you. Fuelling well in training is not just about planning for race day: eating properly on training rides means you optimize your output for that day and you ensure a proper recovery.
Quick overview on race nutrition
- Never compromise on taking food and fluid on rides. Pre-plan stops when necessary or take all your fuel with you.
- Plan your pre-workout meal on long training days. Eat what you will eat on race day morning at the same time. This should be 300 to 400 calories, consisting mainly of carbohydrates. If you drink coffee, drink coffee before training and on race day. Hint: If you are busy and going from work, count back from your planned workout time and eat at the proper time.
- Take in food exactly how you will do it in the race: Open gels while riding, have them in flasks, or cut bars for ease of eating. Don’t do anything new for race day.
- Eat what will be used at your race. PowerBar and Gatorade are the foods and fluids for Ironman worldwide. If they work for you, then you know that you will be OK on race day.
- Do a practice time trial or shorter race and test out eating at speed: make sure you practice eating at the heart rate intensity that you will race at.
Formulating your Personal Nutrition Plan:
1. Before a long workout, lay out your products and make a note of calories and litres of fluid. You should plan for 250 to 400 calories per hour, regardless of source and 2 x 500-750ml bottles of fluid per hour. You may have to plan water stops on your ride. Also take note of electrolytes, ensuring adequate quantities: Sodium: 500 to 1000 mg/hr; and caffeine 200 mg/3hrs. (A PowerBar Double Latte gel served at Ironman has 100 calories, 200 mg sodium, 20 mg potassium, and 50 mg of caffeine)
2. For the first 15 to 30 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 let your heart rate settle. When you have settled into a good cycling rhythm start eating. At this point, start your watch on repeat timer mode, and eat every 30 minutes. (15 to 30 minutes is the average range of eating and drinking intervals.)
3. From 30 minutes after the bike start to 30 minutes prior to the bike finish, eat 250 to 400 calories an hour. (For long training sessions, keep all your wrappers: you will use them later to calculate how much you ate.)
4. Drink 1 to 1.5 l of fluid per hour, depending on your climate and perspiration rate.
5. Eat your last solid food about 30 minutes before the end of the ride, and a gel about 15 minutes before the end of the bike. Take in fluids only for the first 15 to 30 minutes of your run, letting your body and heart rate adjust to running.
6. Typically, athletes can only take in liquid calories on the run, in the form of gels, sports drink or cola. During bike to run transition training, you must take fluids on the run, or have preplanned fluid stations for yourself.
7. Often heart rates are higher on the run, so your ability to consume calories might be 15 to 30 per cent lower. (Making fuelling on the bike even more important.)
8. You should aim for the same fluid intake on the run as on the bike: 1 to 1.5 l per hour.
9. At the end of your workout, count your bars, gels and other food consumed. Add up the calories, sodium and caffeine. Take note on how you felt. This is the foundation for formulating your basic plan.
10. Weigh yourself and compare your post- and pre-workout weights. Every kg lost is equivalent to losing 1 litre of fluid. Dehydration is proven to negatively affect performance, so this is an important step to your success (and safety) on race day.
Performing this routine over and over again in training will allow you to fine tune your own program and to discover the method and foods that work for you. If you are training for an Ironman or half-Ironman, you are doing a lot of work on a daily basis and always playing catch up with calories expended. Practice proper nutrition for any run over 90 minutes or ride over two hours and you will not only be training your body to consume calories on the fly, but you will have stronger sessions and be better able to recover for subsequent ones. This practice becomes your racing nutrition strategy and is fuel for your confidence on race morning.
LifeSport coach Lucy Smith coaches all abilities of athletes and has over twenty years of experience in helping people prepare for race day success. She is a 19-time National Champion and two-time world championship medallist in distance running, duathlon and triathlon.
LifeSport head coach Lance Watson has coached a number of Ironman, Olympic and age-group champions. He enjoys coaching athletes of all abilities who are passionate about sport and personal excellence.