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Running on keto – What to eat before a run

Running is a great form of cardiovascular exercise, it’s almost completely free, and has a whole bunch of health benefits. But what keto low carb food should you eat before a run to fuel your body for the perfect workout? Let’s find out!

The traditional pre-run intake

traditional pre run food

If you’ve ever looked into running, the normal advice is to load up on carbs before a run. What you consume before a run can affect your performance – or so we’re told. The general idea is to eat between 50-60 grams of complex carbs about two hours before a run. This gives your body time to digest and absorb the nutrients.

On a carb-rich diet, your body’s preferred fuel source is carbs as it can be quickly turned into glucose (energy). Consuming a bunch before a run will allow you to run for longer as your body uses the extra energy from the carbs.

Sounds logical, but if we’re on a low carb keto diet then what is the best fuel source to eat before a run? To ask another question, should we skip eating all together before a run and just to do it fasted? Let’s take a look at some of the possible options.

Running on keto fasted (eating nothing)

Some runners swear by eating nothing before a run, this is true for both people on and off a keto diet. Generally, this advice is geared towards short or easy runs as longer ones will require some extra energy.

Personally, for runs less than 10km I don’t tend to eat anything before the run and I feel great! Usually, I run in the morning after a quick resistance workout and the only thing I consume is water. I’ve tried both eating & fasting and not seen much difference, I would even go as far as to say I prefer fasted running. I just feel emptier/leaner if that makes any sense? No food going up and down in my stomach!

With that being said, on longer fasted runs I’ve noticed that I hit a bit of a wall after about 10km, where I’m craving something to eat (or drink) for a bit of energy. On long runs where I’ve eaten something before, I don’t feel like that and would even go as far to say that my performance is improved.

A note on Electrolytes

keto electrolytes

As you may already know, your electrolytes balance may be different while on keto. This is incredibly important when running as you will lose a lot of them (through sweating) on long-distance runs, especially sodium.

You will need to make sure you actively replenish them and the best way to do that is by being proactive! Taking a supplement before a run can help massively and help to avoid symptoms like headaches and cramps.

Check out our article on the best electrolytes supplements to take on keto.

On a related note, if you experience bad muscle cramps after a workout then you might need to take a magnesium supplement.

Eating before a run on keto

So what type of food should you eat before a run? Your body while in ketosis is adapted to burn fat as it’s energy source so you’ll want something high in fat!

As always, make sure you drink plenty of water before (and probably during) your run. You don’t want to get dehydrated halfway through!

There are plenty of keto-friendly low carb food options so we’ve put some of our favourites in the section below.

Best keto food to eat before a run

Depending on the intensity and length of your run you may want to adjust what you eat. Longer runs will require more energy, so increase your intake accordingly.

It’s best to try out a few different things and see how your body responds. For shorter runs try eating nothing before and see how you feel. It’s a good idea to record your thoughts, timings and any other notes so you can refer back and review as needed.

Short runs

5k jog in a park

For shorter runs that are less than 10km in length, you can either run fasted or have a little snack that is full of fat.

Some possible options include:

Nothing – try running fasted and see how you feel.

A handful of nuts – if you’re in a rush just grab a small handful of nuts as a snack such as almonds, hazelnuts and walnuts.

Eggs – doesn’t matter how they are prepared but a couple of eggs are a great source of protein and fat. Hard-boiled is great for a grab on the go snack and best to sprinkle them with some salt to ensure your electrolytes levels are optimal.

Avocado – probably the best pre-running vegetable snack, full of healthy fats and one is great about an hour before a run.

Peanut butter – or any other kinds of low carb nut butter. They are a great source of calories, fat and protein and not to mention they are delicious! Also, you could use a celery stick as the spoon. Less washing up as you get to eat the utensil!

Check our guide on the best low carb peanut butter, as well as our series on other nut butter here.

Fat Bombs – if you have time, you can try preparing fat bombs a few days in advance. They usually consist of a mixture of coconut oil, nut butter, butter, cream cheese and flavourings (like cocoa powder). Just keep them in the fridge and eat 1 (or 2) about 30 minutes before your run for some extra energy.

Fat bomb recipe ideas: My Keto Kitchen / Gimme Delicious / Eat Well 101

Butter coffee and MCT oil – if you want your food in liquid form then a butter coffee is a great choice. Add some MCT oil as that is a great fat fuel source that can be easily burnt during your run.

Check out our ultimate butter coffee guide for more information and what MCT oil to use.

Long runs / Race

long run on tarmac

If you’re running more than 10km or are competing in a race like a marathon, then you will need some extra energy. Again, high-fat foods are a great source for that but you may also need some carbohydrates.

While keto-adapted runners can still run at higher intensities, some carbs may be required to help reach peak performance. If you’re running for longer than an hour, consuming around 10g of carbs can help ensure you run at your best. Of course, your mileage may vary, test and see!

In addition to the foods listed above you can also try doing any of the below:

Fat & Protein – upping your calorie intake with foods high in protein and fat can help make your run easier. Fat bombs are great for this, as they are small concentrated energy sources. Check out some recipe ideas in the short runs section above.

Restrict coffee intake – coffee is a diuretic, meaning it will dehydrate you by making you urinate. You don’t want to get caught short during a long run or race so only have a small cup. You won’t need the caffeine as your body will be plenty pumped enough during the run!

Optional carbs

The targeted keto diet (TKD) is a variation of the standard diet, where you consume some carbs about 60-90 minutes before an intense workout. Its purpose is to utilise the fuel provided by the carbs before it kicks you out of ketosis.

Unless you are experiencing issues with working out such as poor performance and energy levels you probably don’t need to worry about TKD or other keto diet variations. You can read more about TKD here.

After your run

bottle of mineral water

Once you’re run is over you’ll want to make sure you eat something to replenish the calories you burnt. A meal high in fat and protein is recommended and make sure you drink plenty of water!


So hopefully now you have some ideas on what to eat before a run on keto. As always it’s best to try out a few different things and see what works for you!

Great food choices include any kind of nut butter, eggs, avocado, nuts, butter coffee with MCT oil and fat bombs.

You may find that you don’t need to eat anything at all and just let your body burn its fat sources for energy.

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