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Coaches Blog

Should Triathletes Rely On On-Course Nutrition?

Fueling for a middle or long-course triathlon is challenging in the best circumstances. It’s part art, part science, as you figure out your sweat rate, sodium loss, and how many carbs per hour your digestive system can tolerate. 

Throw in the complexity of figuring out which nutrition products work best for you, and it can feel like an overwhelming process. 

Since the announcement that Ironman is switching from Gatorade to Mortal Hydration for North American races, many athletes have been rethinking their hydration and nutrition plans. 

Aside from the obvious recommendation of hiring a coach to help navigate the process, let’s explore some of the big-picture factors in building your nutrition plan for your upcoming 70.3 or full-distance triathlon. 

Factors to Consider When Building A Triathlon Nutrition Plan

Since most athletes can complete a sprint or Olympic distance triathlon with very simple nutrition plans, let’s focus on the middle and long-course distances. 

We’ll start with some individualized factors that will significantly impact your nutrition plan. 

Sweat rate: 

Everyone’s sweat is different, so no “one-size-fits-all” hydration plan lays out how much and what to drink. 

The total amount of sweat you lose, and the electrolytes lost in the sweat vary from person to person. One person might be a very salty sweater, and another athlete might not sweat much or sweat a lot but not lose much sodium. 

Sweat testing helps athletes understand how much fluid and sodium they lose per hour. From there, athletes can generally determine how much fluid and sodium they need to consume per hour. However, dialing in individual needs will still require trial and error during training. 

Calories and carbs per hour:

Carbohydrates are the most important fuel because your body can break it down quickly to give your muscles energy. 

High-carb fueling is all the rage in endurance sports. You might have heard some Ironman athletes talk about consuming as much as 90 grams of carbs per hour!

Generally, athletes who train or race longer than 2 hours can benefit from taking 60-90 grams of carbs per hour as long as it doesn’t cause GI issues. 

It does require intentional practice and “training your gut” to hit the carbohydrate numbers that faster endurance athletes report, proving that endurance racing is as much an eating event as it is a feat of athleticism. 

Generally, the best way to fuel for an endurance event is to consume a mixed carbohydrate sports drink, gels, bars, chews, and other carb sources. 

Should You Rely On On-Course Nutrition for Triathlons?

Once you understand your electrolyte, fluid, and carbohydrate needs, the next tricky step is identifying the specific products that you like and that your stomach handles well. Some athletes experience GI distress with particular ingredients. That’s why it’s critical to test your nutrition strategy repeatedly during training. 

When you add up all the fuel you need for a 70.3 or full-distance triathlon, that’s a lot of gels and chews to fit in your pockets (not to mention bottles of hydration). One option could be to rely on the on-course products, but there are some factors to consider:

Availability of products at each aid station:

Just because the athlete guide says there will be Maurten gels at each aid station doesn’t mean that will definitely be true. 

Athletes near the front of the race can reasonably rely on most things being available, but it’s not uncommon for aid stations to run out of products later in the race (Ironman Louisville 2019 ran out of water bottles at the second to last bike aid station just 6 hrs into the race). 

Additionally, it can be more difficult to predict what products will be available at each aid station of non-Ironman branded races.

Grabbing the products you want takes time:

Continuing with the Maurten gel example, most Ironman races offer regular and caffeinated Maurten gels. Since you probably don’t want to take hundreds of mg of caffeine throughout your race, you must be specific about which gels or chews you want. 

It takes time, even if you pause every few aid stations, to stock up on what you need. On the other hand, carrying what you need and stopping at your special needs bags guarantees what you need is available and reduces the amount of time you need to spend in each aid station. 

Aid stations can be very busy:

This isn’t as applicable on the run course, but aid stations on the bike leg can be busy and dangerous to navigate, with so many athletes going through at different speeds and focused on grabbing what they need. 

For some athletes, this can be a significant factor when developing nutrition plans. Avoiding aid stations can help prevent unnecessary stress. 

Should You Carry Your Nutrition?

The obvious advantage of carrying your own nutrition and hydration products is that you don’t have to rely on anyone and risk not having what you need. The biggest downside is that it takes a lot to fuel an Ironman. 

Even with a very extensive nutrition plan, most athletes can manage to pack enough calories and electrolytes on their bikes and in their back pockets if they plan to stop and re-fill at their special needs bags. 

If you choose this strategy, you’ll only need to grab bottles of water at the aid stations.

Work With A Coach to Develop A Nutrition Plan

Developing a nutrition plan requires expertise and trial and error. An experienced coach streamlines the process with a wealth of knowledge and experience. You'll save time and frustration by reducing the number of things to experiment with. 

A knowledgeable coach will also help you develop an execution plan – how to carry the right nutrition most efficiently on the bike and run.


Gregg Edelstein

Coach Gregg Edelstein is a certified USA Triathlon Level 1 Coach, an IRONMAN University Certified Coach, and a USA Cycling Level 3 Coach based in the greater Boston area. Gregg offers his athletes insight on the principles of exercise, nutrition, sports psychology, and injury prevention, working to make them well-rounded and engaged athletes that share his passion for sport. Gregg can be reached at 


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