If transition is triathlon's fourth discipline, nutrition should be the fifth. Making fuelling mistakes could mean your race ends in disaster. And the longer the event, the more critical your food and drink strategy becomes. But it's not easy. With hydration and nutrition there are dangers in both taking on too much and too little. The key is careful preparation and knowing what you need on the day.
"For races up to about one hour you shouldn't need anything as long as you go into them properly hydrated and carbo-loaded," says Jack Maitland, Triathlon Performance Coach at Leeds Metropolitan University. "As time and distance increase, the evidence suggests that taking on carbohydrates during the race is beneficial."
But how much and how often? "As a rule of thumb, one gram of carbohydrate per kilogramme of body weight per hour is a good starting point," says Maitland.
This is based not so much on energy needs as on your body's ability to absorb it. Exceeding
what the digestive system can deal with may result in discomfort, stomach cramps or a sudden and embarrassing need to dive behind a bush. It's better, therefore, to eat and drink little and frequently rather than gulping everything in one go.
Taking on too little energy will eventually deprive your muscles of glycogen, their main source of fuel, leading to hypoglycaemia ('bonking' in cycling parlance, 'hitting the wall' for runners) and all its unpleasant consequences.
It's worth remembering that the one gram per kilogramme rule is only a guide - tolerance varies considerably between athletes. That means you have to experiment in training. "Never do anything new in a race," says Maitland. "It is very easy to upset your stomach, especially on the run."
Hydration is also critical. Losing more than about two per cent of your body weight during exercise through fluid loss may compromise performance. On the other hand, drinking too much may lead to the dangerous and potentially lethal condition of exercise-associated hyponatraemia (EAH).
The Clinical Journal of Sports Medicine notes that "EAH is caused primarily by the consumption of fluid in excess of urinary and sweat losses. Therefore, it follows that any individual participating in endurance exercise should avoid over-consumption of fluids."
Graeme Hilditch, personal trainer and author of The Marathon and Half Marathon: A Training Guide, believes many athletes, especially beginners, make mistakes with race-day hydration. "Lots of athletes unwittingly drink too much water during a race. This flushes salt from the body and can make you very ill."
The question is how to avoid the potential nutrition and hydration pitfalls. Triathletes face such a bewildering array of nutrition choices that it is not always obvious how to manage the practical details. You might wonder, for example, how to open an energy gel when you're tearing down the road at 25mph.
Start the day well
"I aim to eat and drink properly in the days leading up to the event and then have a big breakfast - usually cereal and bread and jam - about three to four hours before the race," says Steve Worthington, an elite triathlete with a third-place finish in the Windsor Triathlon to his name.
Closer to the race, Worthington may eat a banana and drink a little sports drink or squash. "In theory, I should be well hydrated from the days leading up to the race, so I shouldn't need too much liquid."
In the last half hour before racing he sips water to ensure his mouth doesn't become dry.
Meals on wheels
The bike section, sometimes called 'the rolling buffet', offers the best opportunities to eat and drink. What you consume will be determined by the distance you're racing, weather conditions and your personal preferences and tolerances.
"For sprint-distance races I might carry a bottle of squash or energy drink but wouldn't worry too much about it," says Worthington. "But for an Olympic-distance triathlon I'd aim to get through a bottle of each."
Timing is important. After a long swim it's good to take something as soon as possible but immediately after transition the body struggles with the change in discipline and diverting blood flow to the stomach might cause problems. It's best to wait for about 10 minutes before you start sipping small amounts of sports drink.
As for food, Worthington carries an energy gel fixed to his crossbar with elastic bands, which he usually aims to use at around the 30K mark. He has a neat trick for opening the sachet: "I tape the tear-off tab to the bike. When I grab the gel, the tab stays stuck to the bar." Depending on the type of gel you use, you may also need to drink some water, so make sure your bike bottles are full before you start.
Toward the end of the bike ride, switch from energy drinks to squash so that your stomach isn't working too hard when you make the next transition. If you stick to this plan and you're racing an Olympic-distance triathlon or shorter, you should consume enough during the bike section to complete the run without additional food or fluid intake. On a hot day, take water from drinks stations during the run section if you need to.
Go long, not wrong
While a single gel and a couple of bottles might get you through an Olympic-distance race, longer races demand different tactics and greater carbohydrate consumption, including while running. "It's a big jump from Olympic distance to half-Ironman," says Maitland. "Many people make the mistake of not taking on enough food."
Lyle Butler, a sub-10-hour age-group Ironman triathlete, advises pouring gels into small
race-belt bottles. "I pour six gels into a bottle and stick two to my handlebars with Velcro," he says.
"I put another two small bottles inside a larger one in the cage on my bike, which means I can carry up to 24 gels. You don't want to mess around trying to open a gel with your teeth while riding."
Butler also carries pre-opened energy bars in a pouch on his crossbar and runs with a waist belt packed with more gels and bars. "On the run I drink water or a sports drink at every aid station, but I carry my own gels and bars. That way you can avoid eating something during a race that you haven't tried before. I've done it and the consequences weren't pretty."
A great way to ensure you take on adequate energy is to set the alarm on your watch to chime every 15 minutes. "I keep two bottles in cages on my handlebars, one with water and the other with 20 or so gels," says Richard McChesney, an Ironman veteran, "Every 15 minutes I have a sip from the gel bottle, then wash it down with some water from the other bottle." Gels work for McChesney but he's discovered that he can't stomach commercial energy bars so he makes jam sandwiches and eats them slowly - he sets a countdown alarm on his watch - and washes them down with a mouthful of water. "It might take me 20 minutes to eat a sandwich, as I take only small nibbles, but they keep me going," he says.
"There's an army adage that says something like Proper Planning Prevents Piss-Poor Performance," says Hilditch. "It applies perfectly to race-day nutrition. You have to plan your nutrition strategy and practise it in training. Drinking while running, for example, is a skill you have to learn."
Maitland agrees. "Your stomach does not work so well when you're racing and the six per cent standard concentration of many sports drinks is too high for some triathletes to tolerate under race conditions," he explains. "You don't want to find you're one of those athletes on the day." He advises measuring the concentration of drinks and finding out what you can tolerate by testing everything in training.
So, if you thought mastering triathlon required you to perfect your performance in only three areas, think again. Nutrition is vital and needs as much planning as the three disciplines and the transitions. If you give it the time it deserves, it'll pay you back in style. And results.