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August 27, 2021


Christine VanDoren NSCA-CPT, ACE
Working Out While On the Keto Diet

Fact Checked By Christine VanDoren NSCA-CPT, ACE
 August 27, 2021

Working Out While On The Keto Diet

Few things can benefit you as much as regularly exercising and eating a healthy diet.

But does every diet easily go along with working out?

While the ketogenic diet alone can help you achieve your fitness goals, certain types of exercises work well with it, and some don’t (1).

Learn about the benefits and downsides of exercising on the keto diet and the best ways to maximize your results!

Benefits the diet brings to exercise sessions

It helps you lose weight, which allows for variety in your workouts.

Beyond its initial use for helping children with epilepsy, the ketogenic diet is best known for weight loss.

Thousands of people have lost pounds by decreasing their carbohydrates and increasing their intake of healthy fats.

The more weight that you carry, the more challenging exercise can be, no matter the form.

When first starting your weight loss journey, you may find that seated exercises, walking, and swimming are what you are most comfortable with, as there is minimal stress on the joints and feet.

New exercises and activities will become more enjoyable and manageable as you start to drop pounds because of the keto diet.

Jogging, standing exercises, sports, and dynamic stretching are great transitional activities that will bring even more benefits to your health, as well as accelerated weight loss!


It encourages greater cardiac and energy efficiency.

Not only can the low-carb diet help you lose weight faster, but it can also increase how efficiently your food turns into fuel!

Your cardiac efficiency measures how much work you put in and how much oxygen your body consumes.

Studies have shown that the ketone bodies produced when you are in a state of ketosis can create a higher cardiac efficiency compared to when you are utilizing glucose from carbs alone (2).

The ketones can also increase energy production and the skeletal muscles’ capacity to produce lactic acid during workouts.

Lactic acid is a chemical byproduct that your body produces when exercising; it helps burn calories and increase endurance.

It could make aerobic exercise easier for you.

Examples of aerobic exercises are jogging, running, biking, walking, and swimming.

You can do these activities at a slow yet steady pace for a more extended period to burn those calories.

The ketogenic diet has the potential to make these longer workouts more manageable and enjoyable for you.

With a regular diet, carbohydrates would be the first thing your body would burn as a source of fuel.

However, since you are in ketosis and carbs are no longer readily available, fat burns instead.

Fat tends to be a more steady source of fuel, and it is long-lasting.

Generally, the keto diet can be an excellent tool for anyone who exercises, but it is very beneficial for ultra-endurance athletes.

Potential drawbacks of working out while in ketosis

Anaerobic exercise won’t be easy.

Anaerobic exercises are activities that tend to be very intense and done in quick, short bursts.

While your body utilizes ketones derived from fat as energy on the keto diet, that isn’t what your body is inclined to use during intense exercise.

Instead, your muscles rely on the glycogen that comes from carbs.

Essentially, you will not have as much energy when doing things like sprinting, lifting weights, and climbing stairs because the source of energy your body usually uses will be almost gone (3).

This can result in you being tired during your exercise session and potentially for the rest of your day afterward.

If you feel discouraged because you enjoy going to the gym and lifting but want to try the ketogenic diet, there is a solution.

Many athletes will try an altered type of keto diet that has different rules than the standard.

The targeted keto diet is a variation that allows you to have carbohydrates within 30 minutes of your workout, allowing you an additional source of fuel that won’t leave you feeling as tired (4).

You can also consume exogenous ketones to keep blood sugar levels from spiking so you stay longer in ketosis.

It can be more difficult to gain muscle.

Amino acids are the building blocks of protein.

Eating a moderate amount of protein provides enough amino acids for you to be able to maintain muscle.

It is ideal to have at least 35% of your calories come from protein sources to gain muscle efficiently (5).

On the keto diet, it tends to be around 10-20%.

If your muscles are not receiving enough “food,” they cannot grow.

However, genetics can play a role in this. Some people gain muscle more easily than others, no matter what they are eating.

How to maximize your fitness results

Engage in exercises that target different muscles.

While you cannot target where you lose fat on your body, you can target which muscles grow the most.

Since the keto diet can inhibit muscle growth, it is essential to ensure balanced improvements all over your body.

If, for example, you exercise four days a week, try doing upper body exercises for two of those days and lower body exercises for the other two.

Overall, recomposition of the body can be very rewarding and increase your confidence and physical abilities.

Focus on aerobic exercise.

Instead of going against it, work with the diet by putting your body through a form of exercise that will come easiest to you physically.

For example, try getting in as many walks as you can a week, as they require minimal energy, can take you outdoors, and improve your longevity.

Aim to get your heart rate up through long periods of jogging, rowing, biking, and other aerobic exercises at least three times a week for 20-minute sessions.

Then, over time, increase either the time duration or distance for progressive overload.

Do anaerobic exercise first.

While it was already discussed that anaerobic exercises would be challenging to do on the keto diet, this doesn’t mean they have to be eliminated.

You just need to time it right!

When exercising, you will have the most energy at the beginning.

Use this to your advantage and knock out your anaerobic exercise before engaging in your aerobic activity.

Maximize your protein.

Because the keto diet limits your protein, you must consume all of what the restrictions allow (6).

Missing out on any amount of protein can result in a slower rate of muscle growth.

Also, make sure to consume a large portion of your daily protein right after your workout, as that is when your muscles will benefit from it the most.

Since your primary fuel source changes from carbohydrates to fats on the ketogenic diet, some forms of exercise can become more difficult.

However, there are still many great ways to get your heart rate up and work up a sweat, as your cardiac efficiency becomes greater and aerobic exercises become easier!

Every person is naturally different, but if you take the proper steps towards your personal fitness goals, they can be achieved on the keto diet.