Nutritional considerations for triathletes

Posted by TriProject on May 21, 2016

We are now coming into the competitive triathlon season. What an admirable group of people you are, juggling working life, social activities and training three sports in preparation for those tough competitions on the weekend. Getting the individual training right with correct proportions of, swim, cycle and run, plus recovery and rest is key. But for optimum performance, recovery and strength we need to consider what we are putting into our bodies. Fuel drives all our activities, our brain, muscles and repair, therefore should be carefully considered as an important part of a triathletes training program.

Common Nutritional Issues Associated with the Multi-Event

-       Daily Recovery

During competitive season training loads will have increased therefore expending an increase in energy. You will need to consider eating foods that meet daily nutrient demands and not go too heavy on carbohydrates alone. Common issues with increasing training and not meeting energy demands with food include: persistent fatigue, poor recovery, illness, and unwanted weight loss.

-       Timing of meals and snacks

As you are likely to be training more than once per day in different disciplines you will need to ensure an adequate recovery between each one. Plan your food to ensure regular nutritious snacks are consumed throughout the day, particularly straight after training sessions to begin the refuelling process. Many nutritious carbohydrate foods contain a small amount of protein, which aides in the repair of regenerating proteins used in fuel metabolism and muscle damage incurred during exercise.

-       Carbohydrate Loading

BE CAREFUL, this does NOT mean gorging on pasta the night before or overdoing the carbohydrates the week before competition. As training decreases during your taper your energy requirements will also decrease. For increased accuracy you could work out your energy requirements in order not to over or under eat. You will start to increase your carbohydrate intake to stock up the glycogen stores about 48 hours before the competition.

For sprint and Olympic distance competitors the taper in training leading into the race in conjunction with 7-8 g of carbohydrate per kilogram body weight for 24 hours before competition is adequate to increase muscle glycogen stores. However, athletes competing in half ironman, long course and ironman races should increase their carbohydrate intake to 10-12 g of carbohydrate per kilogram body weight for 48-72 hours before race start. 

-       Pre-Race Eating

It’s crucial to eat a pre-race meal in order to top up muscle and liver glycogen stores. A pre-race meal containing roughly 1-2 g of carbohydrate per kilogram body weight should be consumed about 1-4 hours before racing. (The exact time will vary for each individual and rate of digestion; work out what is best for you between these time frames). The meal should contain familiar carbohydrate-rich foods and fluids that are low in fat and fibre.

If athletes have the early morning jitters liquid meal supplements provide an easily digested alternative to foods. It is also worthwhile to sip on water or a sports drink during the hour before race start to top up fluid levels. The advantage of competing in triathlons is that you can always urinate during the swim if you drink too much beforehand.

-       During Competition

Ironman Athletes will complete Brick sessions in training consisting of a 5-6 hour cycle immediately followed by 1-2 hours of running. Eating during brick sessions is not only beneficial, but also essential.

During sprint and Olympic distance triathlons it is not necessary and certainly not practical to eat foods while racing.

During ironman races where athletes are competing over several hours and consequently miss regular meals, eating food plays an important role in meeting their hourly carbohydrate requirements. The amount of carbohydrate required will vary depending on the distance of the triathlon contested.  For shorter triathlon events, athletes should aim to consume 30-60g of carbohydrate an hour, whereas athletes contesting Ironman events should aim to consume 1-1½ grams of carbohydrate per kg body weight per hour. 

The cycle leg, 'rolling buffet', provides greatest opportunity to consume adequate food and fluid, compared to the run and swim. Athletes are better able to tolerate food and fluid during the cycle compared to the run. It is important to practice or carry a variety of foods to maintain interest and nutritional value.

The run presents many more challenges than the bike in meeting carbohydrate requirements. Most triathletes use fluids such as sports drinks to simultaneously meet fluid and carbohydrate requirements during the run. During ironman events athletes will also use sports gels, as these are far more practical to consume than food while running.

The ideal is to practice what works best for you, fluids or solids, plain or flavor and so nothing new is experienced on Race Day.

-       Fluid Requirements

Scientific literature has shown that some Ironman triathletes may drink in excess of hourly fluid requirements during an event.  Drinking in excess of hourly sweat losses may result in hyponatremia or low plasma sodium.  Slower athletes, particularly females contesting events in cooler conditions are most at risk of drinking too little to replace hourly fluid requirements.  So how do you know how much to drink?  You need to monitor your individual fluid balance during training and competition sessions to develop a plan for subsequent exercise sessions. To measure fluid loss, weigh yourself before training and immediately after training. Be sure to then add the weight of food or fluid consumed, and take into account urine loss. Once estimated fluid loss calculated, divide the total sweat loss by the duration of exercise will provide an estimation of the rate of sweat loss (NOTE: Each kilogram of weight loss is approximately equal to one litre of fluid deficit). Be sure to rehydrate to the appropriate levels.


I hope this tips start you thinking about nutrition whilst you are entering the toughest term in your sport. Practice in training sessions is key, get to know your body and what is required at each session. Remember despite it being the UK, warmer conditions will make you sweat more leading to more hydration needs!


So, do consider nutrition in addition to other strategies and set yourselves up for the best race experience possible. Train hard, eat well, and recover better. Good luck!


For nutritional consultations with a Nutritional Advisor please contact or 0207 924 6068