A nutritionist’s guide to elevating performance for training and racing.

By Breanne Nalder Harward, MS, RDN
Plan7 Endurance Coaching


One of the most common questions I get these days as a sport specific dietitian is, “what do you think about high carb drink mix?” And it’s always a good question. I even find it a challenge to get the right amount of hydration, calories, etc. – all while keeping the guts happy – and I’m a dietitian! When it comes to answering this question for athletes, it’s important for me to establish that I practice what I preach.

When First Endurance sent me the new EFS-PRO, let’s just say I was beyond excited! This mix is designed for high-intensity, long-duration endurance training. It tastes good, and it has the science behind it. I have been an avid First Endurance user throughout my professional career on the road and gravel, and I have always preferred to drink my fuel, so the new EFS-PRO gives me confidence that all my needs are met for reaching my performance potential. 


A big part of my job is making sure that my nutrition recommendations adhere to current science. Fortunately, this is something you can check, and First Endurance products always do. Designs change as science improves, as it should. The purpose of this blog is not to go into the science so much; rather, it’s to give you a better understanding of how to use the new EFS-PRO for your unique body needs.

For a long time in the sport nutrition world, the general recommendation for endurance exercise has been 30 to 60g of carbohydrate (CHO) per hour. But most athletes say that they double their mix or have to adjust with more food to stay up on energy needs, because they burn significantly more kJs per hour.

This creates problems with knowing how to calculate enough calories, electrolytes, and hydration without suffering stomach upset. Using a drink mix that not only meets CHO needs with a sufficient amount of all five electrolytes but also tastes good and doesn’t cause G.I. distress makes for quite the special sauce (yes that is a technical term), making the new EFS-PRO a win-win-win!


I know we’re all here for carbs, but hydration is still an immediate critical need for endurance athletes, and I’d be shirking my duties if I didn’t stress it. How do we know if we are getting enough hydration? First, let me define what I mean by hydration: It’s the balance between water and electrolyte intake that sustains our muscles, kidneys, and other vital organs as we are sweating hour after hour.

It may seem simple, or even a little silly, but the best way to gauge hydration status is to take a look at your pee. Strive for urine the color of lemonade. If it is darker than a light yellow, you need water. If it is on more of the clear side of the spectrum, you need electrolytes.

To get that balance, I advise preloading with EFS-PRO, knowing that you can adjust your hydration status within 30 minutes. Whether this is the morning of and/or even the night before a race or big training day, a bottle of mix can make a world of difference. 


You’ve done your hydration homework. Now let’s talk carbs. The most important thing to remember when fueling for endurance exercise is to base your carbohydrate intake on the intensity and duration of the workout, event, or race.

Most of us know how many calories we burn during our rides from our equipment. Direct kJ output from a power meter, an equated number from a heart rate monitor, data from the smart trainer or online app — regardless of how you get the numbers, pay attention to what you burn on average per hour, then you can estimate what your caloric expenditure will be before you set out to ride.

From there, you can determine how much mix you need to consume in order to stay on top of your energy needs relative to the ride you are preparing for. For example, if you burn 800 calories per hour you would need ~200g CHO/hr. When preparing your calorie/carb counts, note that there are 4 calories for every gram of carbohydrate.

A serving of two scoops of the new EFS pro provides 240 calories (60g CHO), so those caloric needs would be covered with one bottle of mix and one bottle of water on a 90-min ride, or two bottles for a ride lasting 2-3 hours. If your calorie burn is typically higher than that, of course you could put more than two scoops in your bottles – First Endurance recommends going up to four scoops, which is 120g CHO.


The real strategy starts to kick in on anything over three hours, which is considered endurance in the sport nutrition world. At these long durations, it’s an absolute must to stay on top of your carbohydrate, electrolyte, and water intake to maintain optimal performance every hour starting with the first hour. And then you have to follow that plan!

We all know what it’s like to dig a calorie hole that we can’t get out of, struggling to finish a workout or race and kicking ourselves for not fueling better early on. The takeaway here is that you want to dose the number of scoops between your bottles based on your estimated caloric burn per hour.

Here’s a coach’s tip for staying on top of this: Take little baggies with your pre-measured dosage per-hour per-bottle, so when you stop at an aid station or convenience store, you can simply dump the contents of the baggie into your bottles and fill with water. Pre-measured doses per hour eliminate thinking or calculating during a race – you just have to dump the bag and go. And with EFS-PRO’s high concentration of carbs, the volume of mix you’re carrying around is cut in half.


Though EFS-PRO can be portioned to give you everything you need, it is absolutely fine to enhance your energy intake with what I call “security snacks,” especially if you’re someone who likes to chew and swallow during long rides. Whether it’s granola bars, bananas, or other foods that make you happy, the key is making sure you know that it all agrees with your GI system.

Keeping things simple and routine is crucial, so you should always practice your intake strategy during training rides so you don’t have the “would’ve could’ve should’ve” situation come race day. That’s especially true for your main fuel source, so train your body to utilize your sport nutrition by using your mix at the doses appropriate for YOU, and do it EVERY TIME.

I can confidently say that the new EFS Pro is Dietitian approved! Between getting enough mix to sustain what you are utilizing during any given cycling effort and staying on top of those needs every hour, you are getting all your needs met through drink mix alone. Convenient, simple, complete.

Breanne Nalder Harward, MS, RDN, earned a BS in Biology and Sociology as well as a Master of Science degree in Nutrition and Sports Dietetics from the University of Utah. She is licensed as a Registered Dietitian Nutritionist (RDN) in Salt Lake City UT and is the nutrition coach at PLAN7 Endurance Coaching. She raced for the DNA Cycling Team for 6 years and now works as a race director for the Utah Gravel Series and is a mom of two beautiful girls. You can find more info on her at plan7coaching.com or follow her on Instagram @breezysaycheezy.

December 14, 2023 — First Endurance
Tags: coaching


Jeff said:

Hi Breanne,
I did not follow your math on the calories burned vs. consumed / hr in the above article on EFS-PRO. At 800 calories /hr or 200g CHO/hr needed you stated in the next paragraph that the 240cal/hr or 60g/hr CHO would be sufficient. At 4cal / gram of CHO, would you not need 3-4x that / hr? Can you explain?
Thank you,

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