Run Fuelled Or Fasted?

Knowing what to eat and drink before a run can be a concern for some runners.  Some of the typical questions I get from running clients are:

• Should I eat to have energy for a run, or is it better to run “fasted”?
• Could eating before a run give me a stitch?
• What’s best for performance?
• What’s best for weight loss?
• Do I need to “Carb Load” for a race?  And what is carb-loading anyway?
• I feel like I need to carry water when I run, is this okay?

These are the questions that I will be answering in this blog post, read on to find out more…

A lot of the time, the choice of whether to eat/fast will come down to personal preference, and that preference may well change over time.  There have been times in my running history when I have preferred running later in the day whilst feeling more fuelled.  Other times when I prefer to run first thing in the morning, fasted from a night's sleep.

One rule that I always live by though is to never eat a large meal less than 1.5 to 2 hours before running.  That for me is a golden rule which has been learned through experience.  I know that if I break that rule I will most likely feel sick and/or end up with a painful stitch (ah, the dreaded "stitch"... this one is probably worth its own blog post - let me know in the comments if this is one that you would like to see).

Even if neither of those things happens, I can still feel “heavier” if I run after a meal, which creates a more sluggish experience in my running.  So I typically avoid eating before a run.

On a side note, I generally find that I am okay to eat immediately after a run unless it has been a particularly tough session and then I know I am likely to get indigestion if I eat too soon.  Again, this all comes down to personal experience and learning about what works best for you and your body.

Some of my clients prefer to eat something light before a run (such as a banana, or a slice of honey on toast).  Others I’ve coached, feel the need to eat so strongly that they have even gone to the extent of setting an alarm for 4:00 am to eat something before going back to bed because they know they will be running at 6:00 am!

The likelihood is that your body will have enough stored energy to give you about an hour's worth of running (pace and effort level will be a major factor in the actual length of time).  You’ll likely only learn about your own requirements through trial and error.

Best for running performance

Some runners perform best by running on an empty stomach as it helps them feel lighter, whereas others prefer to eat so that they feel energised.

This is another of those personal preference areas.

My personal experience is that this will also depend on the distance, or more accurately, the time you will be running for and the pace (effort level) you will be running at.  Anything up to an hour, and I know that I have enough glycogen stored to see me through.  Any longer than an hour (at a higher effort level, or 90 mins at a lower effort level) and I will need to ensure I start well fuelled and stay well fuelled throughout (see “Refuelling on a run” section below).

If it’s a longer race and I want to perform at my best, then I will also work through a carb-loading phase in the days before (more on that later).

Best for weight loss

Another question I get asked is whether it is better to run on an empty stomach (i.e. fasted) if you are trying to lose weight?

It sounds like a sensible idea, right!?  But, unfortunately, it’s not that simple.

Your exercise effort (whether through running or any other purposeful activity) has very little effect on your weight loss.  Let me say that again - running more or running fasted does not equal any significant increase in weight loss.

Weight loss comes down to a simple equation - eat fewer calories than your body uses up (it really is that simple).  The amount of weight loss will depend on how big that calorie deficit actually is!

Based on this, whether you eat the calories before you run or after makes no difference, you will still be consuming those calories.

Yes, this is a somewhat simplified view and there are other factors that can come into play but these are more detailed than I’d like to go into in this blog post.  I cover nutrition in a lot more detail in our BE Fit Coach Running Coaching Programs.

In fact, nutrition is such an important topic in its own right that we have included it as one of our 7 Core Pillars of Running.

Refuelling on a run

Refuelling on a run for me typically means using energy gels, and using a strategy that I know (from experience) works well for me.

Based on the knowledge that:

1. My body holds enough energy for about 1 hour of harder running AND 
2. It takes approximately 20 mins for my body to process an energy gel sufficiently to increase muscle glycogen stores
3. My preferred brand of energy gel gives me about 20-30 mins of additional energy

I take my first energy gel at about 40/45 mins into the run and then repeat at 30 min intervals.

How often you need to refuel with an energy gel will depend on the manufacturers’ recommendation and your own experience of energy level while using them.

It is worth noting that there is a multitude of different gels available and each one is different.  Some gels just focus on providing a simple carbohydrate hit to increase glycogen levels, while others come with a variety of additional ingredients such as caffeine or electrolytes.

Gels are a convenient way to carry extra fuel on a run but they can cause stomach upset for some people, so make sure you try different options and find one(s) that works for you.

For even longer runs such as ultras, a complex carbohydrate refuelling option is typically better as they provide a more gradual release of energy.

Do your own research and experiment until you find a solution that works for you!

What is carb-loading anyway?

You’ve probably heard the term “carb-loading” before (especially if you know someone who has run a half/full marathon - you know how us runners like to talk about anything running related).

For most runners, carb-loading basically means stuffing your face with as much pasta as you can the night before a big race.  Sounds like fun to me but is this really what your body needs?

As the name suggests, carb-loading is the process of trying to fill (load up) your muscles with the glycogen that comes from eating carbohydrates.  So that belly full of pasta the night before a race will help somewhat, but that isn’t the most effective way to carb-load.

In fact, carb-loading effectively is such an important topic that I will be explaining it in more detail in a future blog post.  Make sure you sign up to my email list to get notified first (I will only ever send you information that I believe to be relevant and useful - no spam).  You can sign up below ⤵️

Staying hydrated on a run

If you want to run at your best then you will absolutely need to be adequately hydrated on your run.  To do that, you need to be hydrated before you even set off!

There is little point in trying to hydrate yourself during a run if you are starting off already dehydrated.  Good hydration is something that you really need to build into your daily life.

The simplest way to check your hydration levels is to examine the colour of your urine.  It should be a very pale yellow colour.  The darker it is, the more dehydrated you are.  There are more scientific ways to check your hydration level and we over those on our BE Fit Coach Running Coaching Programs, but the urine colour test is a quick and easy one to get you started.

So if you are starting off properly hydrated, do you need to drink water whilst running?

The answer depends mainly on factors such as effort level, running time, and the weather.

In my experience, I don’t need to consume water on runs that are less than 1 to 1.5 hours in duration (depending on effort level).  If I am going to be out running for longer then I will either carry water with me or leave a bottle at an appropriate point along the route.

If I am going to carry water though I will always use a backpack with a water bladder (the links are the ones that I am currently using). I strongly advise against carrying a water bottle in your hand whilst running as this can create micro deficiencies in your running gait which can lead to injuries developing over time.

If you want to carry water but don’t want to use a backpack, then a good alternative is to use a running belt with 2 built-in water bottle carriers that are distributed on either side of your body, some examples from Amazon are the Laelr Activ Running Belt with Water Bottles or the Lava Activ 2021 Edition Running Belt with Water Bottles (I haven’t used either of these but the reviews look good).

The other factor I mentioned earlier is the weather.  On hotter days I can find I need to drink water even during sessions that last less than an hour, and especially on tougher technical sessions.  Be mindful of the conditions and always ensure you stay hydrated.

Chat again soon

Barrie

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