When to run on an empty stomach and when to not to

I personally train 80% of my time without eating breakfast. It’s something that I have developed over the years, mostly because of need and not to be cool actually. I have a very sensitive GI system and get the classic acid reflux often, so to avoid running with discomfort I just started to run without eating and yeah, I like it. Bot that doesn’t mean that I do it every time, and actually don’t recommend you to do it every time. 

Here are some tips to run on an empty stomach: 

  • Make sure you had a great dinner the night before, if you don’t, you will run out of energy during your run very quickly. 
  • Start with short and easy runs, avoid bonking that’s not bueno for you so start with the easiest run if you want to try to run without breakfast. 
  • Increase your time slowly, like everything else, step by step. 
  • Avoid acidic stuff before the run, like the ideal combination is coffee and then running, right? Well, yeah, I also love that one but just be careful and understand that running on an empty stomach with just coffee in it is a great way to get acid reflux, GI distress and other potential problems on your stomach, so it’s not an ideal one. 

When to run with an empty stomach and when not too?

Of course it depends on each person, but it’s totally fine for easy and short runs (under 1h), over time you can add more time and hours without problem. The thing is that the intensity will normally remain constant and mostly on the slow side. If you have a long slow run, you can always try and experiment, but always, always have a backup, at least a few gels or a bar, honestly, always have a backup in case you really bonk and are in the middle of the mountains.

When not to run with an empty stomach? When you want to run fast, as simple as that. If you are going for a fast PR or an intensity workout or want to run fast, eat something, even if it is just a banana, it will make a huge difference. 

Remember to always listen to your body, be smart and respect the process and stay healthy. 

Share this post

Keep yourself inspired:

How to Plan your Trail Running Season – an interview with Vert.run coaches Max Keith, Moisés Jiménez and Francesco Puppi

We know that it can feel scary to take time off from training for trail running–especially when you’ve worked so hard to build your fitness during your on-season. But by following some simple, efficient rules (like having a few key runs per week like in our Vert.run off-season training plan) and staying active by doing other activities (like in this Vert.run training program for winter cross training for trail runners) you’ll be able to rest…while also maintaining the fitness you’ve worked so hard to build.

Transitions, Resting, and Recovery

Wherever you are, it’s likely time to pull out different gear. Whether it’s getting warmer or cooler, November is transition time. A

Timeline and VIBE Score: The Complete Guide

VIBE is your daily readiness score, and the Timeline puts workouts and life events side by side. Together they help you decide how to train today and plan the weeks ahead. Log a quick recovery check-in, sync your watch, add life events, and let the data guide smarter, consistent progress.