How to Exercise on the Keto Diet | A Beginner's Guide

Is Working Out On Keto A Good Idea?

Exercising on the keto diet

If planning your keto diet isn’t tricky enough with the constant tracking of your carb intake, then the question of combining exercise and keto is just going to confuse you a bit more. One of your Facebook friends tells you to avoid it at all cost, while your gym buddy says it’s an absolute must.

So, who are you going to believe?

From my own experience. I can tell you for sure that getting to, and maintaining, ketosis is a lot easier when you regularly exercise.

This is something that dieticians and personal trainers can also attest to.

While a targeted ketogenic diet has been proven to be one of the most effective ways for weight loss and getting back in shape fast, adding an exercise routine will burn fat even quicker.

However, making a keto exercise plan has to account for those early weeks to avoid draining your energy levels too much and causing some unwanted side effects.

So, if you’re starting to plan your new diet, then avoid some embarrassment at the gym by setting the right goals for your workouts.

Can You Exercise On The Keto Diet?

You absolutely can and should stick to an exercise plan while on a keto diet. 

Once you have reached optimal ketosis, you’ll be in a great position to exercise even at the highest intensity levels.

There is a good reason why many high performance and professional athletes have chosen to reduce their carbs per day to an absolute minimum. 

man holding rope

Once your body has adapted to sourcing fuel from dietary and stored fat, you will see some significant performance improvements.

So, if the answer is so simple, then why is there such a heated debate about it?

A lot of people, especially critics of keto, simply focus their argument on the low energy levels that are common when you first start out.

During these early days and weeks, they are indeed correct to say that exercising will be difficult, and it can even make some side effects worse.

High-intensity activities like interval training and anaerobic exercise are indeed best avoided during this time. [1] Your body will still be adapting to a sudden lack of glucose, and it wouldn’t be too uncommon to struggle with half the amount of workout as before.

In these early days, it’s best to stick to some light cardio exercise like cycling and jogging. One of our favorites is the rowing machine as you will get most of your body in motion, even at a slow pace.

cycling and walking

Once you get over the initial phase and your metabolism shifts towards ketosis, the argument from these critics completely falls apart. [2]

Keto without exercise will get you to your weight loss goals, but you can get there a lot faster by gradually increasing how often you hit the gym and how intense you train.

Just like with any other diet, where on exercise days you need to increase your calories, in ketosis, you will need to increase your fat intake. You even get a few bonus carbs as well.

It is definitely a counterintuitive statement to say that “to lose fat you have to eat fat,” but throughout the coming sections we’ll try and make some sense out of this.

If you do exercise that is more intense, such as working out more than three days a week and at high intensity, like sprinting or weightlifting, you’ll need to adjust your keto diet to fit your carb needs for your amount of exercise.

Dr. Anthony Gustin


6 Tips For Exercising On Keto Effectively

group of people exercising

The traditional thinking for athletic performance has always been to load up on carbs before any competitive event, or on days when you’re going to be doing some high-intensity work at the gym.

With a low-carb diet, that’s a bit of a problem, obviously. But this is only a problem at the very early stages before your body adapts to ketosis.

Once you’re able to get most of the energy that you need from ketones, rather than glucose, then it’s just a case of managing your diet.

Before you start making a keto diet exercise plan, use the following tips to maximize the health benefits and weight loss.

1. Your Exercise Performance Might ​Drop At First

man laying down on the gym floor

This is something that high-performance athletes often underestimate. 

If you exercise a lot, then you will be fully aware of your energy levels at different stages during a training session. Unfortunately, in the first couple of days, sometimes even weeks, your energy levels will be quite low.

This is purely down to the fact that your blood glucose levels will drop, and your muscles will find it difficult to get the fuel they need to keep up performance levels. 

As a result, you will probably struggle to run or cycle as far and fast as usual. And when it comes to lifting weights, you won’t be able to keep up with the reps.

Keep this in mind and don’t be disappointed: your performance will return to normal.

2. Avoid New And High Intensity Exercises At The Beginning

As your body is adapting to get fuel from new sources, it’s best to avoid new forms of exercises. 

While struggling with your energy levels, it’s not a good idea to add another unknown variable into the mix.

This is the same for high-intensity workouts where you push your body as hard as possible for short bursts. [3]

barbell

Such training requires a lot of glucose and is excellent for fitness improvement and weight loss.

During my first week I almost fainted in a Crossfit session, which was more damaging to my pride than anything else. Don’t let that happen to you.

In the first few weeks, just avoid such training until your energy levels return to normal.

3. Increase Fat Loss With Cardio

man cycling in the summer

One of the significant health benefits of a standard ketogenic diet is substantial weight loss, even without exercise. But if you add light cardio exercises, like cycling, swimming and running, you will significantly boost the fat burning.

Such aerobic exercises will remove any spare glycogen and boost fat oxidation. 

This can help get your body to ketosis faster during the initial phase of your lifestyle change, so it’s highly recommended to plan for this from the start.

Just take it easy for the first couple of weeks.

4. Your Diet Will Need More Fat

A targeted ketogenic diet will already have switched your food intake from carbs to fat. Now before you start thinking about loading up on greasy fast food, you have to remember that the goal is to introduce good fats to your meals (see our keto meal plans page for more ideas).

The ketosis equivalent of carb loading is eating a lot more fats. 

good fats

Exercise will burn more body fat, but for aerobic cardio workouts, it’s a good idea to make some additional fuel available.

It’s a significant change from anything you might be used to, so make sure you don’t accidentally pile up a bowl of cereal.

5. Pay Attention To Your Body

man lying down in fatigue

You should be doing this with all your exercise plans, but it’s even more important while starting out with a lack of carbs. Getting the intensity just right will mean the difference between making side effects worse or getting rid of them altogether.

During each training session, you want to look for signs of fatigue and lightheadedness.

And if you struggle with excessive tiredness after a trip to the gym, then it might be a good idea to take a step back.

However, you will notice improved energy levels after about a week. And when that happens, then it’s time to work your body a bit harder again.

6. Set Gradual Goals

One mistake many people make is that they get to ketosis and then immediately go for high-intensity training. 

The problem is that you still have to get your food intake right and get used to eating enough fat to provide enough fuel.

By setting your training goals at gradual weekly increments, you can make sure that you don’t run low on fuel. 

scrabble goals

And keeping track of your fat intake alongside your training plan will help you get to your goals a lot faster.

A simple diary will do the trick where you note your nutritional intake, exercises and a simple note about how you felt throughout the day.


Frequently Asked Questions:

How Much Exercise Should I Do On The Keto Diet?
You should plan to exercise as much as you need to get to your weight loss and overall health and fitness goals.

However, during the initial stages before you reach ketosis, you will want to take it a bit easy with your training and exercise plan.

light weight dumbells

Aim to run shorter distances and lift lower weights for a week or two until you notice that your energy levels are starting to increase and stabilize again.

Once that happens, there is no reason why you can’t exercise as much as you need to hit your goals.

Can You Build Muscle Mass While On Keto?
You can absolutely build muscle mass with the right combination of keto diet and exercise.

The trick will be to give your body the energy needed to do more reps and lift heavier weights, while at the same time providing enough recovery nutrients.

muscle and barbell

You will already be consuming more meat and fish, but to boost your energy levels, you’ll need to add more fat again. Most meat and dairy products contain a lot of fat and protein, but you’re probably not going to feel like eating a steak straight after the gym.

The ideal solution is to take some recovery protein shakes, as they are refreshing and easy to digest.

Can I Eat More Carbs If I Exercise On Keto?
Yes, you can eat more carbs if you exercise on keto. The good news is that the more you exercise, the more you can increase your daily carbs.

But this is something you will want to carefully increase to make sure you remain in ketosis. And you should avoid increasing your net carbs at the very early stages of the keto diet.

Increasing your blood glucose in this way should also be carefully timed. Essentially, you want to release this extra energy in time for your exercise. 

carbohydrates food group

Generally speaking, your digestive system can start increasing blood sugar within about 30 minutes.

One way to test this out is by using a blood glucose meter. Simply prick your finger every 30 minutes after eating some extra carbs and see how long it takes to get a small spike.

Do You Lose Weight Faster If You Exercise On Keto?
Yes — once your metabolism is in a state of ketosis, you can accelerate weight loss by exercising as well.

If you’re doing a standard ketogenic diet, then you will start losing those fat reserves even with little to no exercise.

But adding some light cardio during the early stages will have two very significant effects.

First of all, it will help your body switch from glucose to ketones quicker by keeping your glucose levels low. 

sexy tummy of a lady

Secondly, once you have reached ketosis, exercise will reduce the amount of ketones in your blood. As a result, your body will trigger processes to burn off more fat, which will help you get to your weight goals a lot quicker.

What To Eat Before A Workout On The Keto Diet?
Before a workout on the keto diet, you should load up on some healthy fats, and you can also take in a few extra carbs.

Just be careful, those carbs are highly precious, and if you overload on certain days, then it can impact your ketosis.

You would run the danger of ending up in a cyclical ketogenic diet, and that can be very difficult to maintain.

bread and butter

As with all diets, the trick will be to find some snack recipes that are high in healthy fat with some protein thrown in as well. 

You should definitely take a look at our meal plans, as they will not only help you to lose the carbs from your plate, but also give you ideas for loading up on healthy fats before heading to the gym.

Does Exercising Help Me Get Into Ketosis Faster?
You can achieve ketosis faster with a regular moderate intensity workout.

The reason for this is that during physical activity, your body will reduce stored glucose. If this glucose is removed and not replaced with carbohydrates, the body will have to find alternative sources of energy.

man doing sit-ups

But planning your initial keto exercise has to account for some initial drop in energy levels. Low-intensity cardio exercises are most suitable at these early stages.

And beyond helping you get to ketosis faster, it will also help you lose more weight in a shorter time period. A perfect win-win situation!

Does Working Out Allow Me To Eat More?
Anyone strictly following the keto diet and exercising will be able to eat more.

In fact, on the days where you plan for more physical activity, you will have to increase your fat intake to provide enough energy.

A small increase of carbs one hour before exercising will also help give you that power boost you’ll need, especially if you’re planning for aerobic exercises.

man eating ice cream

Despite taking in more food, this won’t interfere with your weight loss goals. Being able to exercise will increase your metabolic rate which will help you lose that stubborn stored fat. If all that fails, you can always opt for a pre workout supplement.

Do Ketones Go Up Or Down After Exercise?
After high-intensity or longer exercise sessions, your blood ketone levels will go down, while during aerobic sessions they will actually slightly increase.

The physiological reasons for this are quite complex, and not yet fully understood.

ketone levels

But the theory is that during anaerobic bursts your body will increase glucose production, as it’s the only thing that can satisfy the high energy needs. 

At the same time, ketone production slightly drops and other organs including the brain use free blood ketone. [4]

Exercise on keto, both aerobic and anaerobic, is still highly recommended to improve your overall health and lose weight. Choosing the right mix for your workout sessions is going to require a tricky balance with your food intake.

While the brain has a substantial caloric requirement (at roughly 2% of our body weight, it uses 20% of our resting metabolic rate), you don’t need a ton of glucose or ketones at any one time to power your brain gracefully all day long.

Mark Sisson


Final Thoughts:

Man Doing Exercise

Exercise and keto are the ideal combination to reach your weight loss goals as quickly as possible.

While it does take some careful planning, especially in the first few days and weeks, the rewards of getting this right will be huge.

If you have struggled to lose significant amounts of weight on every other possible diet out there, then this might be just the right combination for you.

But remember: Don’t jump in head first without a clear plan.

If you use the resources on this site to plan both your food intake and exercise, along with the recommended supplements, then you will reduce the initial side effects and get to ketosis considerably faster.

About the Author

Ryan is a personal trainer, athlete, health enthusiast, and entrepreneur. He is researching and expanding his knowledge about the ketogenic diet. He spends most of his time writing content about his new learnings of the ketogenic diet and shares it on Ketogenic Supplement Reviews. You can find me on: Facebook, Twitter and Pinterest.