How to Fuel for a Long Run: Part 3 - Recipe for Success

Updated: Mar 7

This is part three of a three-part series on long run fueling. Read part one and part two.


"What am I supposed to eat on a long run?"


That's probably in the top three questions I get asked as a sports dietitian and a distance runner. It makes sense, because the long run is the cornerstone of most distance training regimens. It's also one area where a fueling mistake can really cost you. At some point almost every runner has found themselves hitting a brick wall of fatigue, feeling the consequences of dehydration, or spending the whole run searching for public restrooms to duck into.


Time to clear up the confusion so you can fuel properly for your next long effort.


The Basics


In part one of this series, we covered the why behind fueling on a long run. So if you're not sold on the benefits, go ahead and click on over to that section and read up before you move on.


To recap, here are the fueling basics: simple carbohydrates are your go-to, particularly at higher intensities (like a marathon or a half marathon). If you're running something under 90 minutes - maybe you're a speedy half marathoner or running a 5K, for example - you don't necessarily need to take in fuel during the run, though you should still plan to eat carbohydrates beforehand and may consider taking sips of a sports drink if you're in the 75-90 minute range. For any run over 90 minutes, you should take at least 30 gm carbs per hour. More seasoned runners can take in up to 80-90 gm/hr for a longer effort.


The amount you can tolerate is determined by your intestine's ability to absorb the nutrition without causing GI issues. Getting fuel from a mix of carbohydrates (i.e, glucose, fructose, maltodextrin, and other sugars) promotes a steady stream of absorption. Your gut can be trained to tolerate larger amounts of carbs, which can benefit your performance (you can check out part two of this series for a lot more detail on that topic).


What to Eat


Okay, so we know that for any distance, you need carbs. But what kind? Should you buy those fancy gels or should you use whole foods? As long as you're getting enough nutrition, it's really up to you!


Gels and chews ("sports foods") are popular because they are quick, convenient, and designed for intake while in motion. They're typically made with a blend of carbohydrates to optimize rapid absorption, so you get fuel into your system faster. They're also easy to eat, even when moving, and easy to carry, which makes them convenient (especially for runners). And it's easy to figure out exactly how much nutrition you're getting based on the amount you consume. However, some athletes have a hard time taking gels with enough fluid to avoid GI issues, or find that certain products really upset their stomach. They're quite sweet (that's the point!) which may or may appeal to your taste buds. And they're usually relatively expensive, which can add up quickly when you're doing a lot of training.


Whole food fuel sources sometimes sit better for sensitive stomachs, and they offer more variety in terms of flavor, texture and price. Whole foods work especially well for longer distances where carrying all your own fuel isn't required (as in an ultra setting with aid stations). A few things that I've had athletes use that work well include squeeze pouches of applesauce, dried fruit like dates or raisins, roasted potatoes, gummy candy, and granola bars. However, these types of fuel are somewhat inconvenient to carry with you - you'd need to eat a whole medium sized potato per hour of activity to get enough carbs in. My running shorts definitely don't have space to carry two or three potatoes, even if they're pureed! Whole foods can also be tough to eat while moving quickly, and can cause problems if you're bouncing around (for example, while running). For many athletes who are hoping to achieve an aggressive time goal, the convenience of sports food may win out when it comes to racing - though you can still incorporate whole foods into your training regimen.


Another option is to use liquids as all or part of your nutrition plan. Some drink mixes, such as UCan and Tailwind, are intended to replace the need to take in additional fuel and give you enough carbs to sustain the effort. However, you'll need to carry enough for the whole effort, which means you might need multiple bottles or a hydration vest. You also need to be sure that the mix is a good fit for your electrolyte and hydration needs, and that you can tolerate the volume of fluid needed to meet or exceed that 30 gm carb threshold. Other hydration products, like Skratch, Gatorade, and Nuun Endurance, contain some carbs but likely not enough to forgo other nutrition altogether. Be aware of what's in your bottle and what it provides, so you can plan to make up the difference with other fuel sources.

If you're an ultrarunner, long distance triathlete, or training for an event longer than 4-5 hours, you should consider taking in a wider range of fuel that includes fats and proteins. The addition of fat and protein will provide a better mix for your body to handle the strain of very prolonged exercise and offers a more palatable variety of flavor and texture. It's also easier for your body to tolerate more complex foods when exercising at a lower intensity. Fortunately, consuming solid foods is more feasible when you have opportunities to stop at aid stations, as in many ultramarathon settings. Practice with these types of foods during training, even if your long runs are 3 hours or less. You want your stomach to get used to what you'll use during your goal event. Consider things like peanut butter sandwiches, trail mix, beef jerky, nut butter packets, or granola bars.


How to Plan your Fueling Strategy


Whatever fuel you choose to use, having a plan is crucial. Winging it when it comes to fueling is a bad idea that can lead to GI problems or bonking with miles left in your workout. A good starting point is to take in fuel starting at 30-45 minutes, and every 30 minutes thereafter. From that basic structure, you can adjust depending on the goals of your run, your tolerance, and your preferences.


Remember - if you have trouble handling nutrition on the run, start small and increase your intakes over time. Take in gels slowly over a longer period of time, practice taking gels on shorter runs to help train your stomach, and get comfortable on the lower end (30 gm/hour) before you attempt larger quantities.


Everyone's stomach is different, so try out different products to find what works for you. I have personally seen athletes with sensitive stomachs have success with products from UCan, Huma, Skratch, Maurten, and Spring Energy, but there are many more great choices out there. Be sure that if you're using a typical gel product that you consume it with water to avoid overloading your gut. A few products like Maurten and SIS advertise the ability to take the gel without water due to their composition - just be aware that these products may contain a different amount of carbohydrates than a more conventional formulation. In addition, you still need to consume fluids to stay hydrated.


If you are an elite or sub-elite athlete with the option to provide your own nutrition on race day, lucky you! You can use exactly what you practice with in training. However, if you are an everyday athlete, you will likely want to spend some time training with the products available on race day to make sure your stomach is good to go for your goal event. To be honest, I even recommend that those who can use their own nutrition try out the on-course fueling options in many cases, because you never know what can happen on race day. You don't want to miss a bottle, drop a gel, or have an issue with your aid station crew and have to use on-course nutrition you haven't trained with!


It's also important to practice the timing of your nutrition. Most races will provide some kind of description of what is available and where the fuel stops are located. Take some time to research when you will have fuel available and mimic the timing during a few training sessions. Fueling works best if it's proactive, which means you can't wait until you're hungry to eat on race day. Don't make the mistake of burning through your stored energy before you start replenishing - get out ahead of it, and avoid a bonk when you should be making a push at the end.


You can't plan for every eventuality on race day! I have a pretty strong stomach and practice fueling regularly, and I still had a few issues with nausea during my most recent race. But by implementing these tips during training and staying consistent, you'll avoid many of the most common pitfalls that may cost you your PR.


Main Takeaways:

  1. 30-60 gm of carbs/hour is the rule of thumb for endurance activity fueling.

  2. Sports food and whole food are both great options for fueling!

  3. Fuel options vary, so test things out to see what works for you.

  4. Practice with the type of fuel you'll use on race day.


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