Triathlon Race Day Nutrition


Basically, what it comes down to is that you have to be very scientific about your nutrition.  Some people refer to nutrition as the “fourth event.”  By being as compulsive about nutrition as we are about the other events we can avoid the problems of hyponatremia (water intoxication or low salt), gastroparesis (stomach bloating), hypoglycemia (low blood sugar), and bonking.


An important aspect of nutrition is to find what works best for you – what is most palatable, what goes down easiest, and what digests easiest.  If you like Gatorade and Powerbars or some other drink or bars then stick with that.  If you have problems with digestion, nausea, or bloating you may benefit from consuming exclusively a liquid diet.   


Race day nutrition really begins with the pre-race meal - a very important component of race day nutrition.  I recommend consuming your pre-race meal approximately 3 HOURS before the start of the race.  This may seem to be an inconvenience, especially given that most marathons and triathlons begin before most of the general population would even think about waking up (especially on a weekend), however this is important.  First, after you consume food, especially carbohydrates your body will release insulin.  This increase in insulin can do two things that will affect your performance: (1) Insulin inhibits growth hormone (GH) release.  Because GH improves your performance, you want to minimize the GH inhibition by insulin.  (2) Studies have shown that elevated levels of insulin before activities results in a faster rate of carbohydrate utilization.  Since carbohydrates are a critical component of the energy needed to complete a marathon, you do not want to use them up too quickly.  Typically it takes 2 to 3 hours after a meal for the insulin levels to return to normal, therefore I recommend eating a small carbohydrate meal about 3 hours before the start of the race. 


A good pre-race meal consists mainly of about 100 to 200 grams (400 to 800 kcal) of carbohydrates.  Fruits, whole-grain breads or bagels, and energy bars make great meals, although your ability to digest whatever you consume is the most important issue.  Individuals who have problems with digestion should probably consume a liquid meal, such as an energy drink and a gel pack.  My traditional pre-race meal is a banana (average of 25 gm carbohydrates or 100 kcal) and a drink made with 4 scoops of Perpeteum mixed with 20 ounces of water (this contains approx 125 gm carbohydrate or 500 kcal).  Perpeteum is a high carbohydrate energy powder made by Hammer Nutrition.  Hammer Nutrition products are unique because they are VERY low in simple sugars and consist mostly of complex carbohydrates (maltodextrin) making them a more prolonged energy source that is easier to digest. 


When discussing race day nutrition it is important to understand the energy requirements.  The average athlete expends approximately 100 calories per mile during a marathon.  During a triathlon, the athlete expends approximately 500 to 1000 calories on the swim, 3,000 to 4,000 calories on the bike, and 2,500 to 3,000 calories on the run.  Wow!  That is some serious energy expenditure.  How does one make up for this humongous expenditure of calories?  Basically, you should aim for 250-300 calories per hour on the bike and 200-250 calories per hour on the run.  More would certainly be beneficial, but most sources state that you simply cannot digest much more than that and trying to over-do it may cause problems, most specifically gastroparesis or stomach bloating.  There are reports of athletes who can ingest more than these levels; ultimately, calorie consumption varies from individual to individual and you need to determine what works best for you.  But, it is very important to develop your nutrition plan during training.  Race day is a bad time to develop a nutrition plan.  It amazes me how many triathletes and marathoners that I speak with that devote so much time and effort to training, yet neglect a good training plan; these athletes ultimately have adverse performance outcomes due to poor race day nutrition.


How can one consume 250 to 300 calories per hour for an entire ironman distance event?  My formula for calories is quite boring, pretty palatable, and very effective.  I use two things:  Perpetuem and Hammergel (  Perpetuem is a nutrition drink powder made by Hammer Nutrition that  has about 130 calories per scoop, mostly maltodextrin (complex carbs), a little protein, and – most importantly – very little simple sugars.  Simple sugars (when you look at the nutrition info on a food or drink product simple sugars are basically the “sugars” listed underneath the “carbohydrate” line) can be bad; they are harder to digest and can contribute to nausea and upset stomachs.  Anyway, if you mix 3 scoops of Perpetuem in a 25 oz water bottle you have a drink that contains 390 calories (equal to TWO powerbars) and is very easy to take-in and digest!  I drink one of these over about 2 hours in addition to a serving of Hammergel each hour for a total of around 600 calories in two hours.  Basically, every 10 minutes I take a generous drink – alternating between water and the Perpetuem (ex – I usually start with water, so 10 minutes into the bike I drink about 4 oz water, ten minutes later 4 oz of SE, ten minutes later 4 oz water, and so forth. 


If you have digestive problems it is a good idea not to consume anything in the transitions and wait about 15-20 minutes into the bike or run before taking in carbs (this is why I start with water and then go to Perpetuem after 20 min.  Another general rule is to drink 1-1/2 pints per hour (16-24 oz – which is roughly 4 oz every 10min or one large water bottle per hour) – of course the SE drink counts as fluid intake as well as calories, ex- in two hours you consume one bottle of water and one of SE which comes to roughly 40 to 48 oz (most large water bottles are 24oz).  Remember, the powder in the energy drink takes up volume, so the amount of fluid in that water bottle will be less.


A quick note on the amounts – gastric emptying is basically the stomach’s ability to digest or empty what you put into it.  As a rule, you get better gastric emptying from a 4-5oz drink every 10 min then you would from taking frequent small sips of fluids.  Generally, the stomach maintains proper function more so from 4-5 oz boluses than it would from a small 1-2 oz “sip” (i.e. the more that goes in, the more that comes out – within reason – be careful not to OVER-DO it).


On the run, I typically stick to the Hammergel, energy drinks, cola, and water.  If you take a serving of Hammergel every two to three miles you should get 200-250 cals per hour.  Remember, it is very important to drink 4-6 oz of water with the Hammergel.  Too dense a concentration of carbohydrate in the stomach can delay gastric emptying and cause bloating.   I find Hammergel very palatable and easy-to-digest as well.  It too is very low in simple sugars, containing mostly maltodextrin.


Just as important as fluids and carbs, is SALT.  Salt (aka sodium) replacement is critical in events lasting longer than 4 to 5 hours (half ironman distance events and longer).  Previously salt replacement was believed to be unnecessary, however recent studies on hyponatremia and electrolyte losses during exercise provide good evidence that salt replacement significantly improves performance.  Endurolytes from e-caps (, SUCCEED electrolyte caps, and LavaRocks are good examples of salt and electrolyte supplements.  I prefer the endurolytes; they contain salt, potassium, magnesium, and calcium.  The medical literature on potassium and magnesium requirements during prolonged endurance activities is not all that convincing, so I do not know if there is a real need for potassium and magnesium (basically, your body has a lot of these electrolytes stored, salt on the other hand is not stored that well and lost in greater amounts), however, it will not hurt.  I recommend two to four salt tablets per hour based upon the temperature, your rate of respiration, and the amount that you sweat.  You can start with two caps per hour, then when it begins to get warmer – about 2+ hrs onto the bike - you can increase two caps every 30 min.  If you have normal kidney function, it is very difficult to use too much salt and very easy to have adverse effects from using too little.  If you have kidney problems, I recommend you contact a sports medicine physician or e-mail me for further discussion.  


Another benefit of salt is that it aids digestion – Sodium helps move water across the cells of the digestive tract.  Therefore, if you feel like you are having some digestive problems, salt tabs can help improve that problem.  Typically, salt supplementation is not needed for events under 3-4 hrs, however, I use salt during marathons more specifically to help with digestion. 


I have worked in several Ironman medical tents.  I tried to get detailed histories from all the athletes that I cared for including their fluid, calorie, and salt consumption as well as the number of times they urinated.  I noticed that a large percentage of the athletes that received medical care used little or no salt replacement.  It helps, it works, it will make you a better triathlete - use salt supplementation.


One last word, caffeine is a performance enhancing drug.  Caffeine aids in the muscle utilization of glycogen (carbohydrate) and may help the liver produce a little extra glycogen.  Typically, I go for a caffeinated gel or beverage (cola, etc) with about halfway through an ironman run (or with about 6 to 8 miles left in a marathon).  I continue to use it every 45 minutes to an hour during the remainder of the event.  It gives my legs a needed additional burst of energy allowing me to finish strong.  The effects are best when you can avoid caffeine for about 5 to 7 days before the event.


I hope this info helps.  I do not claim to be a great triathlete, however, I think that I do the nutrition part of endurance racing quite well (my knowledge of physiology certainly helps).  I know what a let-down it is to train so hard for an event and then have your performance weakened, not by your physical conditioning, but by not taking in the right nutrition.  Again, you have to find the equation that work best for you, but as far as I am concerned Perpetuem and Hammergel cannot be beat.


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