Last Updated: July 8th, 2022

The Keto diet has gained a lot of popularity in the last couple of years. Many people swear on its benefits for losing weight.

As always with the runner’s community, they also try to embrace things that will help them improve their overall health and fitness level. They are also, embracing this diet to reap its benefits.

But the question is, can you run on a keto diet? And if so, how can you do this safely?

Why does the question of safety arise?

Runners mainly rely on carbs as their source of energy, however, Keto being an almost zero-carb diet, eliminates carbs completely. So, naturally, there is a time needed for your body to adapt to this change…

If you rush this process, you may actually harm yourself or may give up too quickly…

So, in this article, we will take up all these aspects and will share a way for you to Keto safely while running, and also will answer some of the more common questions regarding running and the Keto diet.

Can you run on a Keto diet - How to Keto Safely While Running

Can You Run On A Keto Diet?

Yes, you can run on a Keto Diet as long as you are doing it safely. However, due to the nature of the Keto Diet, you may see a drop in your performance for a couple of weeks.

If you are following a Keto Diet or you want to start a Keto diet as a runner, you can definitely do that…However, you should be ready to accept the temporary drop in your performance, while your body is going through the adaptation phase…

But why will there be a drop in your performance…

Before we answer that, let’s understand a couple of things first…this will help you to understand this a bit better…

What is a Keto Diet?

The Keto Diet is a high-fat, low-carb diet with a medium amount of protein in it. You can find a lot of similarities with Atkins Diet or any other Low-carb diet.

If you are on Keto Diet, you will reduce the intake of carbs severely while replacing it with a more healthy fat intake. This will help your body to use up all the carbs stored in your body and will then tap into the fat store for energy.

Essentially your body starts to rely on ketones derived from fat for fuel, rather than glycogen from carbs.

When the body reaches this phase, it has essentially achieved something called ketosis. This is a metabolic state for your body, in which it becomes incredibly efficient in burning up the fat to convert it into necessary fuel for the body.

When your body is fully adapted to Ketosis, you will mainly rely on fat to fuel your runs.

Also, a Ketogenic diet will reduce your blood sugar and insulin levels significantly. This combined with the Ketones will provide you with a lot of benefits.

But how will you know your body is in Ketosis?

We will provide you with some effective methods to check that…

How to check if your body is in Ketosis?

To effectively check if your body is in Ketosis or not, you can check your blood Ketones level with the help of a special meter. This meter measures the level of BHB or beta-hydroxybutyrate in your bloodstream. This is one of the primary ketones that are present in your body.

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An increased level of BHB indicates that your body is in Ketosis.

Your hunger may come down. This may be a result of increased protein in your diet and the increased amount of fiber from the vegetables. Also, the hunger hormone level may get altered due to this diet, which causes this reduction in your appetite.

The ketones also have an effect on the brain to reduce your appetite.

What is keto-adapted mean?

Keto-adapted, also called fat adapted means that your body is using fat as a source of energy instead of carbs. This is a metabolic switch from your body’s perspective.

To become fully fat-adapted, your body takes anywhere between 4 to 12 weeks. However, this depends on a lot of factors like your diet, your body, the kind of metabolism you have, and also to a certain extent your training, etc.

But once you are keto-adapted, your body will become a fat-burning machine and you will be able to see results faster if weight loss is your target.

Once you have achieved this state, to reap the benefits you will have to stay in ketosis…

Staying in Ketosis: How To

If you want to stay in Ketosis, you will have to eat only 30 to 50 grams of carbs in a day – this however varies slightly with the kind of activity you do throughout the day.

If you are running more or doing more strenuous activities, you can slightly increase the number of carbs and still be in ketosis.

However, to reach Ketosis faster, here are some of the foods that you should completely avoid:

  • Bread/Rice
  • Fruits
  • Legumes or Pulses
  • Vegetables that are high in carbs like potatoes, beetroot, etc.
  • Lentils
  • Beans
  • Alcoholic beverages
  • Condiments and sauces (processed ones with a high amount of sugar)
  • Any food item that is high in sugar.

The thing is since Keto is a high-fat moderate-protein diet, you should try to avoid anything that has carbohydrates.

This means, for most of us, we will have to change our diet completely, especially if we are having a high-carb diet. The initial transition phase is a bit difficult, however, if you can stick with it for around 4 weeks, you will be able to reap its benefits.

Benefits of a Keto Diet

Below we have provided you with some benefits of the Keto diet.

However, if you are looking for specific benefits for runners, then what I’m going to say may disappoint you. The research on the effectiveness of Keto for runners is inconclusive. So, bear this in mind while reading through the benefits below.

Helps in weight loss

The Keto diet is an effective tool for promoting weight loss. It improves your metabolism and reduces hunger. The Keto diet relies mainly on protein and fat. Both of these are very filling for your stomach and may help in reducing the hunger-stimulating hormones. Due to the reduction of hunger and improved metabolism, it helps in your weight loss.

Ketones can help avoid the wall

For endurance athletes, the primary source of energy is carbohydrates. They rely on the glycogen stored in their body. However, at one time, the body is capable of storing around 500gm carbs which can produce up to 2000 calories.

This amount of calories is not enough for the marathon and you would need a carb supply on the go. Also, if you are fully depleted of your carb store, then you risk hitting the famous wall.

However, in theory, if you are fully Keto adapted, then your body will use the ketones from the fat as fuel and fat can store up to energy than carbs. This way you may never run out of fuel even with a similar amount of fat.

Improves body composition

When you combine the Keto diet with a moderate-intensity workout, you turn into a fat-burning machine, both during your active phase and the resting phase. This improves your overall body composition and provides you with better overall health.

There are numerous studies and research papers that support this theory. Some are listed below:

Some of the other benefits of the Keto Diet are:

  • Improves acne.
  • May reduce the risk of certain types of cancer.
  • Improved cognitive function.
  • May improve heart health.
  • Improves PCOS symptoms.
  • May protect brain functions.
  • Improved sleep.
  • May potentially reduce seizures.
  • Improved energy levels.
  • Improves focus.

Disadvantages of the Keto Diet

Although there are many advantages of a keto diet, there are some disadvantages as well. Since a runner’s body is mainly used to carbs, the change to a Keto diet may create some adverse responses at first.

These symptoms should go away once your body becomes fully fat-adapted. However, before that, you will feel like s&*t.

So what are some common disadvantages of a Keto Diet?

Keto Flu

When you start a Keto Diet, your body will experience carb withdrawal symptoms. This combined with a change in your gut bacteria and an immune system reaction has the potential of making you feel really bad.

Some of the symptoms may include:

  • Fatigue
  • Nausea
  • Irritability
  • Sleeping problem
  • Brain fog
  • Headache
  • Sore muscles
  • Bad breath
  • Dizziness
  • Cramps
  • Constipation

Loss of Muscle Mass

You may lose muscle mass when you are on a Keto diet. This is an unwanted side effect of doing a Keto diet. This is especially true for people who are doing Keto and are doing a significant amount of training like endurance athletes.

This can also happen if you limit the intake of your protein while amping the level of training.

Although Keto can help significantly with your weight loss, doing this will make you lose weight from your muscle which is not good. It takes a long time to build muscle mass, however, in such situations you will lose it considerably faster.

Now, if you stop Keto and try to gain back the muscle mass, instead your chances are higher that you will gain back fat instead of muscles as that is easier for your body.

Reduction in performance level

When you switch to Keto Diet from your usual diet, you may see a decrease in your performance. This is because your body takes time to get fat-adapted. During this transition phase, there is a drop in your performance.

Actually, carbs are the easiest source of energy for your body. This is more true for runners and other endurance athletes. So, without them, you won’t be able to run that hard or fast.

Also, if as a runner, you are thinking that once you get fat-adapted, you will break your PR every day, then also you are mistaken. There is no research to date that can conclusively tell that a runner’s performance will positively increase if they follow Keto Diet.

So, you may get benefitted from a Keto Diet once you are fat-adapted, but may be more so if you are a long-distance runner. In long-distance running, you need more fuel than your average run and if you are on Keto, you will tap into your Ketone resource.

So, longer, moderate-intensity workouts may be the best benefitted for Keto Diet.

Is running harder on Keto?

Yes, running is harder on Keto, especially before you get fat-adapted. When you are following Keto Diet, you are removing all sorts of carbs from your diet which is the easiest source of energy. Since your body is yet to use fat as a source of energy, running becomes harder.

However, once you get fat-adapted, this may not be the case. But a high-intensity workout may be a problem at that time also…If you are a runner who prefers moderate-intensity long runs, you will be benefitted the most.

If you are going for a high-intensity run, you may not be able able to perform at your previous level. Also, if you keep doing high-intensity runs while you Keto, you risk losing muscle mass.

So, while doing Keto, it is important for you to take care of the amount of protein that you are having. Also, if you are planning on high-intensity workouts, you should focus on the amount of protein intake based on the level of your activity.

Does running help lose weight on Keto?

Yes, running helps lose weight on Keto as it forces the body to tap into the Ketone store. This is because once on Keto, the body doesn’t have that regular supply of carbs.

If your body doesn’t have a regular dose of carbs, as said before it will tap into the stored fat to fuel itself. However, this can be problematic as well, if you don’t watch your protein intake.

When running although you will lose weight on Keto, if you don’t watch your protein intake, you will end up losing protein mass. If you want to avoid that, pay extra attention to the amount of protein that you are having.

Gaining back the lost muscle mass is more challenging than losing it. If you think that you will stop the diet to reverse it, then you are mistaken. Once you stop your keto diet, if you don’t watch your calories, you will end up gaining fat weight instead of protein weight.

Does running help ketosis?

Yes, running helps in ketosis. When you work out, your body uses your body glycogen store to fuel itself. On a keto diet, your body doesn’t have access to this glycogen store. So, it will use the next available store of fuel or fat.

To use fat as fuel, your body has to convert it into ketones. In other words, you will have to go into ketosis.

Also, if you run or workout on an empty stomach your body produces more ketones to fuel your running or workout session.

What is Keto running fatigue?

When you rely on fat instead of carbs for energy during running, in the initial phase when your body is still getting adapted to this, you may experience a dip in your performance level. You will feel low on energy and fatigued, instead of experiencing invigorated. This is keto running fatigue or fatigue caused by the Keto diet.

How to Keto Safely while running?

To do keto safely while running, one of the best possible ways is to gradually ease into it. Also, it is likely that you may be irritable and fatigued in the first few days. Since your performance may go down, you should start a keto diet only when you are not planning to race.

Your body needs 1 to 4 weeks to get fat-adapted and to start reaping the benefits of Keto. So, you should at least take 7 days to ease into the process…Anything lesser than that r if you try to rush the process may further increase your irritability and fatigue.

Here is how you should start easing into Keto safely while running:

Day 1

This day will be the hardest as you are just starting out on your keto journey. On this day have a keto-friendly breakfast and lunch. Also, if possible avoid having dinner. If you are fasting, research shows that you will get into ketosis faster.

Day 2 to 7

Today, start your day with a Keto-friendly coffee. Do any form of exercise but at a low to moderate intensity. You can choose any form of workout, like running, lifting, swimming, or yoga…the key is to do it at a moderate level.

Also, plan since you are allowed to have 30 to 50 grams of carbs on a Keto diet, you should plan for this workout. This will help you to pull through the workout and your fatigue level will be lesser during workout sessions.

By the 7th day, your body should be able to go into ketosis. However, remember that everybody is different and you may take more or less time to go into ketosis…

Madhusree Basu

Madhusree Basu

Author, Admin

Blogger and a fitness enthusiast. She loves running and Yoga and everything in between. She started running to manage her weight and to eat to her heart’s content. A true foodie at heart she shares whatever knowledge she has gained throughout the years about weight management and fitness.