One of the most common questions beginner runners ask is, “How long should I wait after eating to run?” Even seasoned runners often find themselves experimenting with the timing of running and eating, particularly when stepping up to longer distances or when changing the time of day they run.
Because properly fueling your body for a run has a significant effect on how you feel and perform during your workout, it’s essential that you get your nutrition dialed in and figure out how long to wait after eating to run. Below, we discuss the timing of running after eating to help you master your fueling strategy.
To avoid bonking or doubling over with side stitches, keep reading for our best advice on how long to wait after eating to run.
In this guide, we’re going to look at:
- Running After Eating
- What Happens If You Run Too Soon After Eating?
- What Happens If You Wait Too Long After Eating to Run?
- How Long to Wait After Eating to Run
- Rules of Thumb for Running After Eating
Let’s get started!
Running After Eating
Running after eating can be a bit of a tight-wire act.
If you wait too long after eating or don’t eat enough before a run, you may lack energy and find yourself slogging through your workout. However, if you don’t wait long enough and run right after eating, you might find yourself clutching your cramping stomach.
Why is running after eating a potential problem?
Digesting food takes energy. The body increases blood flow to the stomach and digestive organs to start digesting and absorbing nutrients. To compensate, blood flow to skeletal muscles decreases to just meet the basic needs to oxygenate the tissue.
When we run, the heart, lungs, and skeletal muscles demand oxygen and nutrients, so blood flow to these tissues increases significantly. In this case, blood gets diverted away from the digestive tract to feed the muscles.
Digestion slows or nearly stops, leaving food to slosh around in your stomach. Essentially, our bodies aren’t particularly adept at running and digesting simultaneously.
What Happens If You Run Too Soon After Eating?
According to research, because digestion slows or stops when you exercise, running after eating can result in stomach pain and digestive distress. Runners may get cramps, gas, bloating, side stitches, nausea, indigestion, belching, and diarrhea if they go running too soon after eating.
What Happens If You Wait Too Long After Eating to Run?
Running is a metabolically-demanding activity; we need fuel in the form of nutrients (carbohydrates, protein, and fat) to provide energy to sustain exercise.
Fasted cardio or running on an empty stomach can leave you feeling depleted, tired, and unable to perform well. The body has limited glycogen stores since carbohydrates are the body’s preferred fuel source for most runs. Failure to fuel properly or running on an empty stomach first thing in the morning can force your body to be metabolically flexible and burn fat and protein.
While burning body fat for energy is ideal in some ways—as most of us would like to lose body fat—fat oxidation is much slower and in order to keep up with the energy demand, your pace will likely slow down. This is the dreaded “bonking” or “hitting the wall” feeling that many marathoners have experienced around miles 20-22 of a race.
Burning protein is problematic because stored protein comes from skeletal muscle.
How Long to Wait After Eating to Run
Ultimately, the answer to the great debate about how long to wait after eating to run comes down to the frustrating outcome, it depends. The ideal timing for how long to wait after eating to run depends on the following four factors:
#1: Your Digestive System
Though “it depends” often feels like a stock answer or evasive way to respond to a question, the reality is that the human body is highly individualized, and we all respond somewhat differently.
Therefore, one of the primary reasons that there aren’t universal rules for every runner across the board as to what works best for running after eating is because every runner has a unique digestive tract.
Runners with sensitive stomachs may only be able to tolerate light, small snacks before running and may need to wait a lot longer after eating to run than a runner with an “iron stomach.”
For example, one runner may be able to eat a peanut butter and banana sandwich, head out for a run 60 minutes later, and feel perfectly comfortable and energized, whereas another runner would be left in stitches, cramps, and running to the nearest bathroom.
Our gastric emptying rates vary, and some people have digestive tracts that are more affected by the jostling and stimulation of running, which makes running after eating less feasible.
#2: The Workout
How far and how fast you plan to run is certainly a factor in the optimal fueling strategy including what you should eat and how long to wait after eating to run.
For short, easy runs, you’ll need far less fuel. You can not only eat less but also don’t need to wait as long after eating to go out for your run. The more intense your workout, the more blood the body has to divert from the digestive tract to your working muscles. This leaves the food sitting in the stomach like a heavy weight.
On the other hand, with easy runs, there’s a less dramatic shunting of blood from the gut because the workload on the heart and muscles is reduced, allowing the digestive tract to process some of the food as you exercise. Therefore, your body can usually handle more fiber or protein in a pre-run snack if you’re just running an easy recovery run.
If you are attacking a hard workout or race, the muscles compete more aggressively for the bulk of the blood flow, so digestion is put on the back burner. Accordingly, you’ll need to wait longer after eating to go run a hard workout and should stick with easily-digestible foods like simple carbohydrates with little fat, protein, and fiber.
#3: The Time of Day
From a practical standpoint, how long to wait after eating to run is somewhat dependent on the time of day.
From a fueling standpoint, it might be ideal to have a larger snack or meal and wait longer before heading out for a long run. However, if you have to hit the road first thing in the morning to fit in your miles before work, you may not have the luxury of this longer digestion window.
If you can’t wait as long after eating to run, you may have to opt for a very small snack just to top off glycogen stores right before heading out instead of a more substantial fueling option. In other words, the practicality of our lives largely dictates how long we can wait to go running after eating.
In these cases, it makes the most sense to work backward: determine how long you’ll be able to wait after eating to run and then decide what your body will be best able to digest and assimilate during that time.
For example, if you have an hour or so and your digestive system is fairly agreeable, you might do well with a banana or half a protein bar. If you only have 30 minutes, a couple of dates or dried apricots or a sports drink may be best.
One other note on time of day: theoretically, the later it is in the day when you head out for your run, the more you’ve eaten throughout the day before the run. If you have sluggish digestion, this may mean that your gut is still processing food from earlier in the day and you may need to wait longer to digest your food before running.
You also already have the nutrition from the better part of the day still on board in the body, so you’re starting from a much more fueled state than running first thing in the morning after the overnight fast. As such, you won’t need as much “fuel” before your workout.
#4: What You Eat
What you eat and how much you eat largely affect how long to wait after eating to run. From a volume standpoint, the more you eat, the longer you’ll need to wait to go running after eating because it takes your stomach longer to fully empty a larger volume of food.
The caloric content and nutrient breakdown of the meal or snack also affect the gastric emptying rate. Studies show that the average stomach empties at a rate of approximately 1‐4 kcal/min, so the more calories you eat at one time, the longer it will take your stomach to process the food.
Protein, fat, and fiber also take longer to break down, so digestion will be slower if your pre-run meal or snack is something other than simple carbohydrates.
Rules of Thumb for Running After Eating
Even though we’ve established that how long to wait after eating to run is dependent on several factors and also highly individualized, there are some general recommendations for the timing of running and eating:
- Wait 3-4 hours after a large meal to run
- Wait 2-3 hours after a small meal to run
- Wait 1-2 hours after a snack to run
- Wait 30 minutes after a quick bite or an energy gel to run
Of course, you’ll want to experiment with what foods work well for you and the optimal timing of running after eating for you personally.
You can check out our complete nutrition guide for more ideas on what to what before, during, and even after a run!