During a middle distance triathlon, or a 70.3 as it is called, it is common to encounter athletes who did not do a good race, and they often mention nutrition as the main reason why things did not go as planned.
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The nutritional issues for an athlete during a middle distance triathlon are:

• Running out of fuel, "hit the wall" , to break or simply not being able to maintain the intensity during the last part of the race.
• Become progressively dehydrated to the point of limiting performance.
• Problems gastrointestinal problems , such as stomach cramps, bloating, diarrhea, etc., and which can have a negative impact on your performance.

The main fuel for an event like this is carbohydrate, especially if you are completing the race closer to the 4 hour mark than the 7 hour mark. Body reserves contain about 500 grams of carbohydrates (that is, 2,000 kcal), not enough to last until the finish line. In theory, it should be enough to get most athletes through the first 3 hours of a 4-7 hour race, but it's essential to recharge from the start (i.e. take supplements in the form of gels and liquids). As it takes a while for carbohydrates to be absorbed, it is recommended to start early with your intake to avoid carbohydrate depletion. Once you've depleted your carbohydrate reserves, it's difficult to recover the damage.


Energy
As a general rule, aim for 60 grams of carbs per hour. This carbohydrate can be in the form of a bar, gel, gum or drink. If you indicate solid foods, make sure the fat, protein and fiber content is low (no more than a few grams). What the athlete uses is entirely up to him and his personal preferences.
Faster athletes tend to use more liquids and less solids because it can be difficult to chew at high intensities.

To get an idea of ​​what 60 grams of carbohydrates per hour are equivalent to, we can indicate one of the following combinations:

• 2 gels and a small amount of Power Powder;
• 1 gel and 1/2 dose of Power Powder.

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What about hydration ?
It is good to use the beginning of the race, when the gastrointestinal tract is working well, to absorb carbohydrates and fluids. Later, even if the athlete is thirsty, the intestine may not absorb as much. The goal should be to lose a little weight (no more than 2kg) by the finish line. You definitely want to avoid weight gain, which would clearly be a sign of drinking too much fluid. In hot environments, dehydration can definitely be a very important factor. Good hydration starts before the race, and recommend good hydration in the days leading up to the race.
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Gastrointestinal problems
A large percentage of athletes, approximately 30 to 70%, experience gastrointestinal problems during a 70.3. Some of these issues are very minor, but some of them can be so severe that they affect performance. Some athletes are more likely to develop these problems than others, so self-knowledge is essential. Complaints can be completely independent of food intake and can sometimes only occur on race day. This suggests that “race day anxiety” has something to do with it. Studies have also shown that factors such as fiber intake, fat intake and the use of highly concentrated carbohydrate drinks are causes of gastrointestinal discomfort.
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Common mistakes on test day:

• Stick to a plan at all costs - If for some unforeseen reason the athlete cannot follow the plan (lost a bottle or is developing gastrointestinal problems), do not continue with the plan, be flexible and adapt. A little less intake won't be a problem, while too much will probably be.
• Don't try something new on test day. Only use products that you have tried and tested before, products that you know you tolerate well.

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Extra point:
Caffeine (low dose: 3 mg/kg one hour beforehand) may help some athletes. Some like it, others don't. Experiment and find out what works for you - and no testing on test day.

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These are the basics of good fueling for a 70.3. Many athletes don't get the basics right and others worry too much about other aspects and get distracted by details. Plan your strategy in advance with your nutritionist and have a rough idea of ​​where you will get your carbohydrates (drinks, gels), how much liquid you will need to drink and where you will get it from (transport, special needs or feeding stations).
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Make sure to reach at least 60 g/h of carbohydrate intake and enough fluids so that he doesn't lose too much weight or run out of energy. And good luck!

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References: Rehrer NJ, van Kemenade M, Meester W, Brouns F, Saris WH. (1992) Gastrointestinal complaints in relation to dietary intake in triathletes. Int J Sport Nutr. 2(1):48-59.

Baker LB, Jeukendrup AE. (2014) Optimal composition of fluid-replacement beverages. Compr Physiol. 4(2):575-620.