Keto And Exercise: How To Workout On The Keto Diet

Keto and exercise – are the two compatible? There are some people who believe that the keto diet is not suitable for intense workouts due to its low carb content. Their position is that you need a good store of carbs to give you the energy to sustain prolonged exercise. Is this correct? So lets talk about exercise on a keto diet.

Exercise On A Keto Diet


One thing to immediately point out is that many of the criticisms directed at keto when it comes to athletic performance is that it completely ignores the presence of ketones as fuel! The mistake many make is to think that carbs are the only source of fuel humans can use – thereby completely missing the point of the keto diet! Yes, of course you can’t exercise without adequate fuel but fuel doesn’t only come in the form of carbs. You have plenty of fuel – fat! If you’re in ketosis, you have all the fuel you need.

But, yes, there is an argument for saying your workouts might change a little bit when you’re on a keto diet. You might find you’re stronger in some ways and a little bit weaker in others. You may have more endurance for some exercises and less in another.

Understanding what’s going on in your body when you’re on a keto diet will help you understand how best to train and get the most out of your workouts.

Despite what some people think, exercising on keto can produce great benefits but you will need to understand a few key points before designing your exercise plan.

So, let’s break down the different styles of working out that you should be doing on a keto diet.


The first thing you should start doing is harness your body’s “creatine phosphate system” when training. To do this, simply start lifting heavier weights with fewer reps. The creatine phosphate system is an energy system that your body uses in certain situations (generally highly explosive, lower rep training) instead of relying on carbs.

Adjust your workout to start lifting in that 1-4 repetition range. This will ensure your energy comes entirely from the creatine phosphate system and you’re not having to rely on any carbohydrates for fuel.

Low reps are the key. That’s how the creatine phosphate system works – by fuelling the first few reps only. (After the first few, the body will seek out carbs for fuel).

As the name suggests, the creatine phosphate system only uses your body’s creatine stores – and only replenishes itself from these stores also. You will need to ensure your creatine fuel tank is topped and while creatine is present in beef, pork, fish it is easily destroyed in the cooking process – and so supplementation may be necessary.


There is no need to “carb up” before a workout. The Journal of Metabolism actually found that conditioned athlete ended up having just as much glycogen stored in their muscles if they were on a keto diet, than those that weren’t on a keto diet. This shows that you still have sufficient carbs stored in your muscles to give you fuel for your workout.

So there’s no need to change things up, to add carbs or do special periodic carb timing etc. Just train the way you would normally train and your body is going to adapt just fine.

When it comes to endurance training you’re definitely going to want to make sure that you train as close to a fasted state as possible. This will allow your body to tap into its stored body fat reserves a lot easier. You see, when you’re doing endurance work your body is already wanting to use fat as a fuel source whether you are on keto or not. It’s a process called beta oxidation.

This is why keto is so effective for weight loss because you have a twin effect going on. When you’re in ketosis, your normal daily activities are burning up fight and when you add exercise to that, your workouts are burning up fat also. You’re a fat-burning engine.


When you’re on the keto diet, your body becomes duel-fueled. Your body can run on carbs when it needs to but also run on fats. So when you’re working out slowly, your body will use fats. When you start increasing the intensity, your body will tap into stored carbohydrates.

When you train in a fasted state, your body has the ability to switch between carbs and fat more easily



You may hear some people suggest the Cyclical Keto Diet for those on intense exercise regimes. This is where you follow the keto diet for, say, 5-6 days then have 1-2 days eating carbs. The argument is that for high-level or elite athletes, simply relying on fat for fuel is not sufficient. However, this is simply untrue given the sheer caloric density of fat.

It’s been said that a cyclical keto diet is really nothing more than an excuse to deviate from the standard keto diet. The fact is, many people are literally addicted to carbs. (The keto flu has been described as nothing short of withdrawal symptoms). And, just as no one in their right mind would advocate an alcoholic having a drink once a week, there’s no reason why we should suggest the same for those on the keto diet.


Now one of the reasons why people want to do carb cycling is for physical performance, they feel better – generally because they’re not fully adapted to burn fat. (Full adaptation can take up to six months). So, until they’re fully adapted, carb cycling feels good because it fixes the low blood sugar that makes them feel tired.

But, if you stick with the standard keto diet without carb cycling you will find your body does eventually become fully adapted to burn fat for fuel. You will no longer suffer from the low blood sugar energy dip.

Those who persevere with the standard keto protocol find they are able to switch over the fat burning very easily. Endurance athletes who have been in ketosis for months burn up to three times as much fat. Their systems become very efficient at burning ketones and there is no drop in physical performance at all.


Elite world class athletes who swear by the keto diet include:

  • LeBron James
  • The Australian Rugby Team
  • Chris Froome – Three-time winner of the Tour de France
  • Paula Newby-Fraser – Eight time Ironman World Champion
  • Zach Bitter – Ultramarathoner, holds the 100-mile American record and 12-hr world record

Consider this. The average human body can only hold about 1,700 calories in stored carb reserves. Contrast this to 77,000 calories in stored fat reserves. The difference is huge and there is only one logical reason for this: our body is meant to burn fat for fuel.

If you carb cycle, the fact is you never fully break free from your carb addiction and your body never fully adapts to running on ketones. The fact is, it takes times to switch from burning sugar to burning fat. (Whereas it’s very easy to go from burning fat to burning sugar).

The takeaways is: don’t carb-cycle. Instead, persevere and give your body the time and opportunity to fully adapt to burning fat. And if your body needs glucose, it will make it. (The liver has the ability to make glucose out of protein and out of fat through a process called gluconeogenesis.)


High Intensity Interval Training (HIIT) is absolutely possible on the keto diet – and recommended. Again, do your HIIT training in a predominantly fasted state.

The Journal of Physiology published a study that looked at

three different groups: Group 1 consumed a high amount of carbs; Group 2 were on a carb-cycling regime and Group 3 consumed a high-fat, low-carb diet (i.e. the ketogenic diet). What they found was that Group 3 (keto) ended up oxidizing (burning) 2.5x more fat as the other groups.

So the keto diet actually encourages the body to burn more fat for fuel.

The next point to note is that when you are doing HIIT cardio, you’re elevating what are called catecholamines. Catecholamines are hormones made by your adrenal glands including dopamine, adrenaline, norepinephrine etc. These hormones help regulate physiological functions such as your heart rate and breathing rate but they also trigger lipolysis (the breakdown of fats). You need catecholamines to burn fat.

So, we have 2.5x fat oxidation combined with catecholamines combined with a fasted state which makes fat burning easier, and you have a triple compounded fat-burning effect. In other words, your HIIT training just became an insane fat-scorching furnace.

You definitely don’t want to be skimping on your HIIT training while you’re on keto.

Finally, remember that keto is a low-carb diet, not a no-carb diet. People who say high-intensity exercising is not possible on keto often forget this. You do have carbs in your system in the form of vegetables. And if you stick to the points above, you will find that not only is it possible to workout on the ketogenic diet, you may actually see improved results in terms of fat-burning.


Burn Your Fat


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