Pre-Run Snacks: When to Eat and What to Eat for Energy on Your Runs

What to Eat Before Running: Your Guide to Pre-Run Snacks

One of the most frequent questions I receive from athletes is about pre-run snacks. Trends of fasted running, fears of GI distress, and early morning alarms all compel runners to sometimes skip a pre-run snack. Athletes may not know what to eat before a run. This article delves into what to eat before running for optimal performance with minimal discomfort. 

Why Should You Eat Before Running?

No matter what time of day you run, a pre-run snack enhances performance by literally putting fuel in your tank. During running, your body uses carbohydrates in the form of glycogen and glucose (and to a certain extent, fat) as a fuel source (substrate) for energy production. As a 2018 meta-analysis in the Scandanavian Journal of Medicine and Science in Sports points out (and most runners can attest to based on real life experience), pre-exercise eating improves aerobic performance. 

A pre-run snack is especially important if you plan on running a quality session (speed work, fartlek, hills, tempo, long run, etc). Whenever you run above aerobic threshold (approximately marathon pace for a majority of runners), you burn a higher percentage of calories from carbohydrates. These energy demands require easily available energy. Not eating before a run can hinder your performance and therefore the benefits of the workout. Even if you prefer to run your easy runs fasted, you want to ensure you at least consume liquid calories before a hard workout.

If you are running before breakfast, a pre-run snack serves the purpose of topping off your body’s carbohydrate stores. The overnight fast of sleeping can deplete up to half of your glycogen (stored carbohydrate). Eating before your morning run provides glucose, which allows your body to spare glycogen and have adequate energy for the session. In practical terms: you will feel more energetic and have a more productive training session.

More research indicates that within-day energy availability affects athletic performance. If you are a morning runner or running in the evening after work (several hours after your last meal), a snack will fill in a window of otherwise low energy availability. According to a 2020 review in Nutrients, regular windows of limited energy availability increase injury risk (particularly stress fractures), decrease performance, and may cause cardiovascular, endocrine, and gastrointestinal dysfunction.

When you run in a fasted state, your body searches for alternative fuel sources. It will burn fat – however, the more your body relies on fat oxidation, the lower intensity your session will be. Additionally, your body will also break down your muscles for protein to turn into glucose via gluconeogenesis, as demonstrated in a 2011 study in Strength and Conditioning Journal. When your body breaks down your muscles, your injury risk increases. (You can read more about why fasted running does not improve performance here.)

What If You are Prone to GI Distress?

The most important thing to remember is that your stomach is a muscle; you can train it. Gut training is highly effective for runners. Essentially, if eating before a run causes GI upset, you teach your stomach to handle it. First, you gradually introduce small amounts of food (think half of a banana) and eat that before your runs for a week or two. After an adaptation phase, then slowly increase the amount and allow time for your body to adapt.

Not only is hydration vital for running; it can prevent GI upset. Even minor dehydration will cause your body to pull water from your gut into your bloodstream. Less water in your gut means poorer digestion, which will increase the chance of stomach upset. Be sure to drink a glass of water or electrolyte drink with your pre-run snack.

What to Eat Before Running

Ideally, you want to select easily digestible foods (not high in fiber) that are high in carbohydrates. You may choose to add a bit of fat or protein for satiety. However, both fat and protein are slower to digest, so you may opt to avoid those if eating shortly before a run.

  • Graham crackers
  • Banana, plain or with nut butter 
  • Bar, such as ClifBar
  • Toast or half a bagel with honey or jam
  • Roasted/boiled red potato with salt
  • Sweet potato with honey
  • Juice or sports drink
  • Applesauce
  • Honey Stinger waffles

How much you will eat will vary on the training session. A general guideline is 1-4 grams of carbs per kilogram of bodyweight, according to a 2018 review in Current Sports Medicine Reports. The exact amounts within this range will vary on the time between eating and your run, the intensity of your session, and the duration of your session. If you are eating 2-4 hours before your run, you will eat more than if you eat 1 hour before your run.

A quick guide if you are eating right before your morning run:

  • Easy run under 70 minutes: 25-75 grams of carbs
  • Long run (90+ minutes): 50-100 grams of carbs (or more)
  • Hard workout (60-90 min): 50+ grams of carbs

What NOT to Eat Before a Run

It is generally recommended to avoid potentially irritating foods or foods that are slow to digest in the couple hours before a run. If you notice GI upset following the consumption of these, it may be worth avoiding them before a run.

  • Dairy products: milk, cream, cheese, yogurt
  • High-fiber vegetables, especially broccoli, cauliflower, kale
  • Beans/legumes
  • Meat
  • Alcohol

Ultimately, though, every runner is different. Maybe you can have a green smoothie before a run and be fine! Alternatively, you may find that the normal options such as peanut butter do not sit well with you. Use trial and error and consider what you are eating and when you are eating when finding a pre-run snack that works for you.

When Should You Eat Before Running?

Individual factors must be considered in the timing of a pre-run snack:

  • Time of day: early morning run or did you just eat lunch a couple of hours ago?
  • Digestion: Is your stomach sensitive?
  • Duration of run: Longer runs require more food before, which can mean more time to digest.

Ideally, you want to allow 30-60 minutes for a smaller snack to digest, such as a banana or graham crackers. Runners with stomachs of steel can usually run less than an hour after eating even a sizeable snack. For larger meals, allow 1-2 hours to digest. If you need more than 2 hours to digest, consider trying other options to see if they digest better.

Use your hunger as a cue for running after meals. If you are feeling ravenous already, have a small snack of 25-50 grams of carbs. If you just ate a full meal a 1-4 hours ago and do not feel hunger, then that meal will carry you through the run (if it provided enough carbs).

Caffeine May Add a Performance Boost

Caffeine offers numerous benefits for runners, including improved athletic performance, extra alertness, and help in emptying the bowels before a run (which we all know, is as essential as a pre-run snack!). The International Society of Sports Nutrition recommends 3-6mg caffeine per kilogram of bodyweight in the hour before exercise. (If you are running later in the day, use caffeine cautiously or avoid it if it can impact sleep.) If you are not a regular coffee drinker, begin with about half of a cup before a shorter run to see how your body responds. If you observe any adverse effects such as GI distress or anxiety, skip caffeine before a run.

However, coffee does not contain carbohydrates. Do not rely on coffee alone as your only pre-run fuel! Pair coffee with water/sports drink and your pre-run snack.

What’s your go-to pre-run snack?

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9 Responses

  1. Great tips, Laura.
    It’s true what you say about diary – it makes my stomach feel heavy and slightly off during a run. I now eat some almonds and walnuts about 2 hours before I leave. Perhaps not the best option, but so far it works well.

  2. Every week I make a batch of oatmeal bars that have been perfect to snack on while I drink my coffee in the morning. It gets tricky when I lift early and then run with Grayson around 7. I’ve had a protein smoothie in between and luckily my stomach handles it ok. I also like eating honey stinger waffles before a run.

  3. It all depends on when and how far I am going. For an early morning run, I often just drink a cup of coffee and go. Sometimes I’ll drink a bottle of Tailwind. If it’s a long run, I will drink a smoothie and give myself an hour or so to digest.

  4. I was a fasted runner for years and years because I worked out first thing in the morning and “didn’t have time to eat”. After a period of low energy last winter I decided to start having a banana before easy runs and UCAN before hard runs…it seems like I had “time” after all. It made quite a difference and I never looked back. Today b/c of WFH I now have coffee and Cliff bar before most workouts, if I’m not super hungry then I’ll have a cereal bar.

  5. I tried fasted running a while back and it did not work for me at all. I had no energy. Since I am able to run mid morning, I eat breakfast and wait and hour and then run or workout. So far, that’s my best strategy

  6. Thanks for all this concise information. I usually eat a banana before a run but I’ve been slacking off lately. Not sure why but I’m going to get back on it!

    One of the reasons I am a morning runner is that I could never get the food thing right for an afternoon run. I’d end up either too hungry or uncomfortable.

  7. Most of the time I arrange it so my runs are close enough to a meal that I really don’t need a snack. I’m lucky I can do that! Otherwise I’ll have some Honeystinger chews, or sometimes dark chocolate covered ginger. 🙂

    Fasted running is really not for me, but I know there are some people who swear by it.

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