Fuelling an ironman starts long before race day and finishes long after. Here’s what you need to eat and drink to ensure optimal preparation, racing and recovery

“Competing in an ironman event places huge physiological and psychological demands on an athlete and therefore correct preparation is key,” explains Glenn Kearney. A big part of this preparation should be centred on nutrition as this is vital for performance. “Nutritional preparation not only includes race day nutrition,” says Kearney. “But also includes how you adapt  your diet in the build up to such a demanding event in a way that compliments your training and sets you up with the best chance of performing at your highest potential.”

Expert Glenn Kearney is the head sports nutritionist at Etixx UK (etixxsports.com) and has previously worked with UK Athletics.

Adapting your diet

“You will need to make changes to your day to day diet to compliment your training schedule to allow you to fuel and recover,” says Kearney.

  • Aim for an all-round balanced diet consisting of carbohydrates, protein, healthy fats, vitamins and minerals.
  • Increase your carbohydrate intake to meet your increased demands for fuel. Taper your carb intake each day relative to exercise intensity and duration.
  • Increase your intake of high quality protein to assist in muscle growth and repair.
  • Eat 2-3 portions of healthy fats per day – remember that fats are used for fuel too.
  • Fill your diet with plenty of vegetables as they provide essential nutrients such as fibre, potassium and iron.

Pre-Race Nutrition

In the week before your ironman there are a few things you can do to properly prepare. “Firstly, decrease your fibre intake as it takes much longer to digest,” says Kearney. “This can subsequently cause GI (gastro-intestinal) problems and distress. Secondly, increase your carbohydrate intake to ensure you are properly fuelled for your event – but don’t go overboard and be left feeling heavy and bloated.”

Pre-race dinner – your dinner should be something which you have tried and tested a lot on nights before long and intense training sessions. Usually this will contain a high proportion of carbohydrate along with protein, but pre-race dinners can vary greatly from one ironman to another – knowing what works for you is vital. Pre-race breakfast – on race day ensure you eat breakfast about 3-4 hours before the event starts and aim for a breakfast high in slow release carbohydrates.

“There may also be some physiological benefits of taking on caffeine and this should be done around 60 minutes prior to the event,” advises Kearney. “But practice your pre-race breakfast and experiment with caffeine before your training sessions and find out what works for you.”

Fuelling your event

“It’s essential that you also plan a nutritional strategy for the ironman,” says Kearney. As muscle glycogen depletion is one of the main causes of fatigue, taking on additional carbohydrates will be essential for maintaining performance. “It is recommended that during a prolonged endurance event you should aim to consume 60-90 grams per hour of multiple source carbohydrates,” adds Kearney. “Throughout your event you shouldn’t take on significant amounts of fat and protein as these are harder for the body to digest and process and may increase your risk of GI distress.”

Strategic eating

How you take in carbohydrate is up to you. “You should have enough glycogen stored to last you the swim and therefore the majority of your fuelling strategy will take place on the bike,” says Kearney. This is where it is easiest to store food and is most convenient to consume it. “Refuelling should begin soon after you have settled into your bike ride to allow time for your food to digest before your run as otherwise you could be left feeling bloated and heavy.”

If you are using real foods as part of your strategy, try to do this at the beginning of the bike ride. Some good food ideas include a banana, sweets, Jaffa cakes and flapjacks. “As this is such a long event, you may want a savoury snack on the bike as well – a bagel with some marmite or peanut butter would be a good option.”

Once you get further into your bike ride and nearer to the run section, or if real food doesn’t work for you, consume carbohydrate in the form of energy drinks, gels and bars. “These are absorbed and digested quickly and therefore provide energy efficiently whilst limiting the risk of GI distress,” adds Kearney.

“Get to know the carbohydrate content of the food and products you are using and how best to time your intake and remember that carbohydrate can also come in the form of drinks which are easily stored on the bike and can play a key role in your hydration strategies.”