24October

Nutrition in Preparation for Triathlons

It is important for triathletes to ensure meals and snacks are based around nutritious carbohydrate foods to meet daily fuel and nutrient demands. Persistent fatigue, poor recovery, illness, and unwanted weight loss are common symptoms amongst triathletes who don’t adequately meet their daily energy and nutrient requirements.

Timing of Meals and Snacks

As triathletes are required to train 2-3 times daily, recovery from one training session to the next is crucial. Planning their daily food intake is vital to ensure regular snacks and meals are consumed around training sessions. It’s important to have nutritious carbohydrate snacks on hand immediately after training to initiate 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

The concept of carbohydrate loading is popular amongst triathletes prior to competition. Carbohydrate loading is more than simply eating pasta for dinner the night before competition and certainly doesn't mean gorging yourself with food for the entire week leading into a race. As training decreases leading into a race, energy (kilojoule) and carbohydrate requirements also decrease. During an easy week prior to competition it is important for athletes to taper food intake accordingly to avoid unwanted weight gain immediately prior to racing. To adequately fill muscle glycogen stores (carbohydrate stored in the muscle), athletes need to consume between 7-12g of carbohydrate per kilogram body weight for 24-48 hours prior to 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. For further details refer to the Carbohydrate Loading fact sheet under the ‘Competition and Training’ section http://www.ausport.gov.au/ais/nutrition/factsheets/competition_and_training

Pre-Race Eating

The majority of triathlons start early in the morning so there is the temptation to miss breakfast before race start. 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 meal should contain familiar carbohydrate-rich foods and fluids that are low in fat and fibre. For instance two English muffins, 1½ tablespoons jam, 1 teaspoon Vegemite and 750 ml sports drink provides 2500 kJ, 125 g carbohydrate, 2 g fat, 14 g protein and only 4 g fibre. Foods like liquid meal supplements, sports bars, bananas and juice are also popular pre-race meal choices.

Eating During Training and Competition

Eating food during long training rides is essential for triathletes to help provide carbohydrate to the working muscles, meet daily energy and nutrient requirements and keep hunger at bay. Most ironman triathletes complete "brick" sessions during their preparation for an ironman triathlon. Brick sessions may consist of a 5-6 hour cycle immediately followed by 1-2 hours of running. Eating during brick sessions is not only beneficial, but essential.

During sprint and Olympic distance triathlons it is not necessary and certainly not practical to eat foods while racing. Due to the high intensity of racing, athletes competing in these events usually rely exclusively on sports drinks and sports gels to meet fuel and fluid losses. However, 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.

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.  For example, a 70kg male athlete contesting an Ironman event should aim to consume roughly 70-100g of carbohydrate an hour.  The athlete’s tolerance will ultimately dictate how much carbohydrate is consumed and should be considered when deciding on a race nutrition plan.

The cycle leg provides the best 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.  Athletes should take a variety of food on the bike to ensure they maintain interest in what they are eating. Sandwiches, fruit bars, sports bars, bananas, sweet biscuits, dried fruit and sports gels are all examples of foods commonly eaten by triathletes while cycling. It is good practice to have a combination of regular food items and sports foods.

The run presents many more challenges than the bike in meeting carbohydrate requirements. Most triathletes use fluids such as sports drinks and soft drink 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.

Meeting Fluid Requirements during Competition

During competition, it’s not as simple as drinking as much as tolerated or possible. Recent reports in the scientific literature have 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 in excess of 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.

 

By Jana Mellor
Senior Dietitan

Source:  AIS Sports Nutrition, last updated April 2009. © Australian Sports Commission.

Posted in Wellbeing, Diet, Exercise, General

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