Exercising at the Gym on a Ketogenic Diet

adjective Chemistry.of or derived from a ketone.


Exercising at the Gym on a Ketogenic Diet

When starting out on a weight loss journey many individuals opt to go for the ketogenic diet. Since this greatly reduces carb intake and our bodies traditionally use carbohydrates to fuel exercise activities, people rightly wonder what their options are when they workout or go the gym.

What is the Ketogenic Diet?                                                                  

This aim of this diet is to force the body into a fat-burning state. This is achieved by severely limiting our traditional source of energy – carbohydrates. The diet is predicated on eating high amounts of fat, sufficient levels of protein and minimal levels of carbohydrate.

By eating in this manner you force the body to stop using carbohydrate as the main source of fuel for energy and instead use fat. When a body burns fat as a fuel source rather than carbohydrates it enters a state know as “ketosis”.

What is Ketosis?

Ketosis is the result of the body not being able to produce enough glucose from your carbohydrate intake. When this happens, your body releases your fat stores to be broken down for glucose production, producing ketones.

These ketones can then be used for glucose production instead of breaking down sugar. Therefore, when in ketosis, your body has changed its fuel source from carbohydrates, to fats.

Once in a fat burning state, people find it much easier to lose excess weight stored as fat since it is now their primary source of energy. Once in ketosis, many individuals undergo rapid fat loss, losing weight and improving their physique as a result.

Exercising on the Ketogenic Diet?  

As previously mentioned, with this diet you are burning fat not carbohydrates, therefore it makes sense to try and stick to fat-burning activities. As a general rule of thumb, low-intensity exercise known as “aerobic” exercise is fat burning whereas “anaerobic” high-intensity exercise the body still likes to utilize carbs, even when in ketosis.

So when you visit the gym you want to be looking at doing activities such as a brisk walk, or a slow jog on the treadmill, you could try a cross trainer on low resistance or maybe set the rowing machine to an easy setting at go at a slower pace for an extended period of time.

If you want to (or need to) do high-intensity exercise such as lifting weights or sprinting for your particular fitness goal, then you need to slightly adjust your diet. Eating roughly 30 grams of easily digestible carbs (such as fruit) in a 30-minute window before exercise and again immediately after finishing your workout should yield the best results.

This ensures you have enough available glycogen to perform the activity to the best of your ability and also allows your muscles to recover properly. Using carbs in this laser-focused way also means that you are in control of what the body is using them for, you lessen the chance that they will be utilized for any other activities later in the day, safeguarding your state of ketosis.

Benefits of Exercise While on a Ketogenic Diet

There is a wealth of evidence to suggest that exercising while on a ketogenic diet is beneficial as opposed to a hindrance to the body.

One study noted that after a 3 hour long run taken by a group of low-carb eating distance runners that they in fact they were able to burn 3x more fat and replace the exact same of of muscle glycogen as the control group of high-carb eating distance runners (see the study here).

Another noted that being in a state of ketosis helped maintain blood glucose levels during exercise for a group of obese individuals on a weight loss program (see study results here). So it’s clear to see that the ketogenic diet provides a good foundation for your exercise plan.


Overall, the ketogenic diet has many well-publicized benefits, namely that you force the body you burn your excess fat stores, leading to rapid weight loss once the body reaches a state of ketosis.

But many don’t know how to supplement this diet with exercise. It is clear that low intensity aerobic exercise is very keto-friendly, because of its use of fat as an energy source.

Always aim to include as much aerobic activity as you can. A good target is at least 3 separate 30 minute aerobic workouts a week, and if you manage to increase this to 5 workouts a week you will see a bigger change in your weight and quicker results.

However, this does not mean you can’t do or should avoid high-intensity workouts. If you want to do something explosive like lifting weights or sprinting, just make sure to supplement your diet with a small amount of fast-acting carbs just before and immediately after exercise to see the best results.

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