Keto & Running: How to Run a Keto Marathon

Keto & Running: How to Run a Keto Marathon

Posted by Katie Spaller on

You’re thinking about running a keto marathon, so you’ve heard of it: the Wall. That seemingly inevitable point in the race – maybe mile 18, maybe mile 21 – when your energy stores empty out and the struggle becomes acute. The scenario can be scary: your glycogen stores are empty, that runner’s high you were soaring on for all those miles is now turning into a crash. But is this scenario really inevitable? We don’t think so. We think you’ve got a choice: plan for when you hit the Wall…or train your body to avoid it altogether.  

In this article, we’ll lay out the elements of running a keto marathon while using fat as a source of fuel, and how keto endurance is not only an attainable goal, but a smart element of any training program. From world record holders in the timed 100 miler (like Zach Bitter) to newer runners looking for an edge to maintain their energy levels during endurance events, keto marathon training is becoming a recognizably valuable tool. It takes consistency – allowing for proper fat adaptation – and discipline. Of course, nothing worthwhile is easy. But you want to enhance your performance and get the most out of your body’s potential – so keto marathon training could be your path to defeating that dreaded Wall. 

Can You Run a Marathon on a Ketogenic Diet?

Others have. Why not you? 

As you begin your keto endurance journey remember this: it takes time. As you know from your marathon training, miracles don’t happen – adaptations happen. And fat adaptations derive from consistency and volume from running on keto. The same way you need time and consistency to get your cardiovascular and musculoskeletal systems conditioned to the stresses of distance running, you’ll need time and patience to prime your body to become efficient at burning fat. 


The benefits of keto diet over carb diets are there – it increases fat burning, conserves glycogen, and is good for the brain and the mitochondria (the “power generators” of your cells). But don’t expect it to happen overnight. The primary goal of a keto diet is limiting carbohydrate intake and burning fat for fuel.

After all, you do that long run in your training each week to both prepare your muscular skeletal system for increased stress, but to also train your body to get better at using fat as a fuel source. It’s commonly said in the running community that most of us could run several marathons on fat stores alone. But we’ve got to train and condition our bodies to do that, which is where a smart keto endurance approach can help. 

Does Running Speed Up Ketosis?

There are many questions surrounding keto and running. According to the Cleveland Clinic, ketosis occurs naturally after prolonged exercise and when you follow a keto diet ( Longer and easier-paced aerobic runs push your body to rely on its fat stores for fuel. A full body exercise like running depletes glucose stores faster, which in turn speeds up ketosis.   

Athletes who are adapted to a keto diet and to efficiently using fat as a primary fuel source have an advantage – they can efficiently and effectively use two fuel sources for energy: ketones and carbohydrates. In the long run (and during a long run, of course), ketones are a better fuel source over glycogen at those endurance activity exertion levels, particularly in fat-adapted folks. So having ketones in the system spares the glycogen in muscles so you can use it when you need it most – those moments in training or a race when you need to run faster, or sprint to the finish. 

Is Keto Good for Endurance Running Long Term?

Relying on the keto diet and using fat stores over glycogen can help keep those energy levels stable. During those later miles of your keto marathon training – and the race itself, to be sure – keto endurance adaptation can get you a steady supply of energy to keep you moving during your endurance event. 

Something else to remember: your brain needs energy too. Just like with other physiological and energy systems, long distance running depletes your brain of glucose and fuel. And any runner can tell you, once the brain is depleted, the body wants to quit. Refocusing yourself to a keto runner that uses fats for fuel can keep your brain powered up, which will help your body persevere to the finish line. Fats and ketones can keep the brain fed and happy. And exogenous ketones can help you recover from exercise by increasing glycogen synthesis and mitigating skeletal and muscle breakdown.


What Do You Eat For a Keto Marathon?

Just like your running training itself, binges won’t get you there, so keep it balanced. Yes, it feels good to eat all that bacon and cheese, but make sure to eat a lot of vegetables and healthy fats: avocados, nut butters, chia seeds, and the like. You’ll need a substantial amount of healthy fats in your diet to keep energized. That’s your best keto running fuel. 

Exogenous ketones can also be the key to running on keto. According to some studies, exogenous ketones increase the breakdown and use of fat as an energy source, both for the body and the brain.   


How Do You Train for a Keto Marathon?

Like we said earlier: don’t look for miracles; look for adaptations. And adaptations take time. So, the first rule is to be patient and consistent and don’t look for instant results. Some things to try as you dip your toe in the keto endurance waters: do your morning runs on an empty stomach to enhance your fat burning capabilities. And the big one: supplement your diet and keto marathon training with exogenous ketones. That’s where Kenetik comes in. 

Here is what our exogenous (and delicious) ketones can do for a runner:


  • Raise energy levels
  • Provide electrolytes
  • Aid in recovery


As far as sports nutrition, using a ketone drink like Kenetik is also the fastest (and easiest) way to get your body into ketosis. 

As they say, if running marathons was easy, everyone would do it. The hardest part is usually just deciding to go for it. And with consistency, patience, a solid strategy, and using all the tools available – including a keto diet and Kenetik – you can get more out of your body than you ever thought. 

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