fueling on the run article cover image. Title text on image showing common gus and gels

The Runner’s Complete Guide To Fueling On The Run

Fueling through sport drinks, gels, beans, or natural foods is an important part of achieving peak performance on your run. It is also important to jump-start your subsequent recovery. As a certified running and nutrition coach, I often tell my coaching clients that what they consume on the run, can make or break their race or long run and set them up for how they feel in the hours and days to follow.

In this guide, I discuss the basics of endurance fueling and when fueling is necessary. I explain what happens if you don’t fuel properly, and I share tips on how to pick the right foods to fuel with, how to use them, and how to avoid the dreaded stomach distress that often comes with using engineered foods like gels and sport drinks. Read to the end, because it may not be gels and sport drinks that are causing it!

Fueling for long runs and races is a very individual thing. Proper fueling is more than just opening a GU pack every few miles. For example, your level and quality of training, your metabolism, your genetics, and the intensity at which you run are just some of the things that can impact how much fuel you need on a run.  Mess up in any of these areas, and your fueling strategy falls short.

General Guidelines to Endurance Fueling for Runners

When we run, our body pulls energy from a few sources, the most common being fat stores, and glycogen found in your muscle cells and liver.  As we consume food, carbohydrates top off our glycogen stores so we can store it and use it for later.  Each day, our body pulls energy from both fat and glycogen.  That is an oversimplified view of a very complex biochemical process that is impacted by a lot of factors.  For example, the better trained you are, the more glycogen you can store,  up to a point.

So during a run, or race longer than 60-90 minutes, it is generally advised to fuel with some form of carbohydrate source.  For most distances under the marathon distance of 26.2 miles, these work great.  For ultra-runners you will want to add some real food options in to help your stomach feel full, and not consume too much sugar.

Now, there is a thing called, fat adaptation, where almost all your energy comes from fat stores, but that process is beyond the scope of this episode.  Generally speaking, that is a long process (several months) and requires a diet with extremely low carbs, and moderate protein to achieve.  For the purpose of this podcast, we are going to focus on the most common way of fueling for endurance athletes and that is using gels, wafers, sports beans, and blocks/chews.

How Much of Endurance Fuel do I Need?

In order to keep from bonking, the average runner will want to consume about 100 calories and 25 grams of carbs for every 30 to 45 minutes of activity when runs are 60 minutes or longer. This is generally one gel pack. However, make sure you read the nutrition information because this varies from product to product.

Unfortunately, many people don’t train with a specific fuel type and just grab it if it is being held out at a water stop at a race and therefore some suffer some consequences from it. This is usually a bad idea.  The first rule is to use what you train with.

What are the Most Common Types of Fueling Options for Runners?

There will always be natural food sources that work well for many but usually aren’t as easy to carry with you. That is why many runners prefer the following options: sports drinks (like Gatorade, Tailwind, etc) were created and why other engineered foods like gels, wafers, chews, and sports beans were created.

  •  Sports drinks (like Gatorade, Tailwind, etc)
  • Energy gels
  • Performance wafers
  • Sports chews
  • Sports beans

One thing to note is that all fuels are not created equal.  Some come with caffeine (which is a stimulant that can help with mental focus and a slight performance boost) and some without caffeine.  When using products with caffeine, it is important to not over-consume them, or it can make you jittery, or even cause gastro-intestinal issue which is the last thing you want on a run. You should avoid BCAAs (Branched Chained Amino Acids) as they have minimal effect on endurance fueling)

Others vary in terms of the amount of sodium and potassium that are included.  These are two important electrolytes that every runner needs to replace as they run.  For more information about these two electrolytes, please check out RunBuzz Episode 85, where I talk about staying hydrated, and I go into a lot of detail on the importance of these electrolytes when it comes to staying hydrated and the performance impact these electrolytes have on you.

My Recommended Energy Gels for Runners

Honey Stingers – I like Honey Stingers as they are organic and are made up of 100% real honey, as well as they contain electrolytes.

Clif Shot Gels – Clif Shot are another one of my go-to gels simply because they are easy to find (and often handed out at races). What I like about them is that they have a bunch of flavor options, so if you find one you don’t like, there are many more to choose from.

Once you narrow down the types of fuel, only do one kind at a time. If you purchased a couple of different brands or consistencies, try them out on different days so you know how each one affects you. Especially caffeine and caffeine-free options.  A great place to get samples is race expos and at some running stores.

Help! Gels Upset My Stomach!

Stomach distress after consuming gels, beans, or chews is a common objection I hear on why most people avoid them. I understand your frustration! GI distress during runs is no fun, and sport gels and drinks can definitely be culprits. But they are not the only reason. But fret not, let’s dissect the potential causes and find solutions to get you back to running smoothly.

Causes related to sport gels and drinks:

  • Osmotic Load: Gels and carbohydrate-loaded electrolyte sport drinks are often concentrated to provide quick energy. This high concentration can draw water into your gut, causing bloating and discomfort.

  • Ingredients: You might be sensitive to specific ingredients like fructose, artificial sweeteners, or thickeners. Experiment to identify potential triggers, or try products like Tailwind or Honey Stingers which tend to be easier on your stomach.
  • Volume: Consuming too much, too quickly, can overwhelm your digestive system. Pace yourself and take smaller, more frequent sips/bites.
  • Temperature: Cold fluids can sometimes irritate the gut. Try room-temperature or lukewarm options.

Causes beyond sport gels and drinks:

  • Dehydration: Running depletes fluids, leading to reduced blood flow to the gut and impaired digestion. Stay adequately hydrated before, during, and after your run.
  • Food choices: Pre-run meals high in fiber, fat, or protein can be difficult to digest during exercise. Opt for easily digestible carbs 2-3 hours before your run. I have an article called What To Eat Before A Run, that has lots of suggestions on pre-run fueling.
  • Under-eating: Not consuming enough fuel can lead to low blood sugar and GI distress. Ensure proper pre-run fueling and consider mid-run snacks for longer runs.
  • Running intensity: High-intensity workouts divert blood flow from the gut to working muscles, potentially causing digestive issues. Adjust your pace or training plan if needed.
  • Underlying medical conditions: Certain medical conditions like irritable bowel syndrome (IBS) or lactose intolerance can be exacerbated by exercise. Consult a doctor if symptoms persist.

Tips to prevent GI distress:

  • Experiment: Find the sport gels and drinks that work best for your gut. Consider less concentrated options or DIY recipes.
  • Hydrate: Drink plenty of water throughout the day and during your run. Aim for small, frequent sips.
  • Fuel smart: Choose easily digestible pre-run meals and mid-run snacks. Focus on carbs and avoid overloading with fiber, fat, or protein.
  • Pace yourself: Start slow and gradually increase intensity. Listen to your body and take breaks if needed.
  • Stress management: Pre-run nerves can trigger digestive issues. Practice relaxation techniques like deep breathing or meditation.
  • Consult a doctor: If symptoms persist or worsen, rule out any underlying medical conditions.

When it comes to fueling,  there are a lot of factors in play, so I recommend working with a coach who has experience working with athletes with not just their running, but also their nutrition needs. A sports dietitian is another great option.

How to Use Gels, Beans, Wafers and Sports Beans

  • You do not need fueling or sports drinks for runs under 60-90 minutes.  Once you start getting into runs lasting longer than that, without fueling you will probably notice how run down or tired you are getting. This is a good time to start trying them out. For most of us, this is somewhere between 5-10 miles into your run.
  • For half marathon distances and below, one trick is to figure out at what mile or time in the run do you tend to feel tired or start to get hungry. Once you start tracking that, you will want to start fueling a mile or two before that point.
  • For marathon and ultra distances, I recommend fueling and hydrating right from the start, especially if you will be out there longer than 4 hours, and especially if you did not nail your training. Starting early is necessary because you will reach a point where you can’t absorb fuel as fast as you use it up. So, the idea is to start replacing glycogen immediately from the start.
  • Always take fuel with water.  Do not mix sports drinks and gels. Ever.  Sports gels are concentrated and need water to dilute them. Failure to do this will potentially lead to stomach distress.  And make sure when you take on water, that you take on enough to dilute the gel appropriately.  You will want to follow the instructions on the gel packet or the manufacturer’s website.
  • Another tip is to check your race’s website for water stop locations so you can train to take your fuel of choice just before or at the water stops.
  • Finally, pay attention to how you feel after taking it. You should notice a slight boost in energy shortly after taking it.  Never take more than what is recommended on the packaging. More fuel won’t make you feel better as you can only absorb so much at a time anyway.

Alternatives to Energy Gels

There are plenty of people who use sugar/carbohydrate-based fuel such as Starburst candy, gummy bears, honey sticks or dried fruit for a quick energy boost. Just be sure to avoid high fiber foods as they can bother your stomach. Fig Newtons would be awesome, but the fiber gets a lot of people. That is also the issue with Bananas, etc.

I like Combos snack pretzels, especially the peanut butter filled ones because they have carbohydrates, salt, and protein.  The problem though is that I don’t like to carry them so I usually stash them in my car or at a water stop.

When you Train with Fuel, Don’t Let Race Day Nerves Throw off Your Plan

Often nerves can get in the way on race day.  If you get nervous before a race, it can mess with your appetite and you may not feel like fueling. However not following a fueling plan can lead you to start to crash and then feel too sick to be able to take the gel later.  Do everything the same on race day regardless, because you trained that way and your body expects it.

Pre-Race and Post-Run Fueling for Runners

Pre-Race Fueling

For runs longer than an hour, it is important to eat a light snack of around 400-500 calories 1-2 hours before your race. Having a good mix of carbohydrates, proteins, and fats, will help you top off your glycogen levels that were used up while you were sleeping. Skipping breakfast on an endurance race can be disastrous.

Post-Run Refueling

Within 90 minutes of completed activity be sure to eat a light meal, containing carbohydrates, proteins, and fats.  Get something in you as soon as you can. 30 minutes is better than 90, but no more than 90 as it really slows down reabsorption. It takes 48 hours or more to reabsorb and top off pre-run glycogen levels if you waited more than 90 minutes, but it can be done in 24 hours or less  if you eat right away and periodically throughout the day.

Your post-run recovery begins the minute you stop running!