Fact-checked by Dr. Anthony Gustin, DC, MS.
Written by Lorenz Mac
One of the most important rules to the ketogenic diet is to restrict carbohydrates from your diet and replace them with healthy fats.
On the other hand, the cyclical ketogenic diet encourages you to eat high in carbohydrates one to two days out of the week.
Doesn’t that defeat the purpose of keto?
While the standard ketogenic diet can help you lose weight, there’s some speculation that you may struggle with building muscle and increasing strength on keto.
While this claim isn’t backed by research, if you’re still concerned or just not able to commit to going full-keto, the cyclical ketogenic diet (CKD) may be for you.
The cyclical ketogenic diet is for the more advanced dieters and recommended only for people who have already successfully adopted a standard ketogenic diet in the past.
CKD helps your body turn carbohydrates into muscle instead of storing them as fat.
But to receive the benefits of muscle gain and fat loss, you can only consume a certain type of carbohydrates and within a specific timing protocol.
In this article, we’ll talk about:
The cyclical ketogenic diet (CKD) follows a standard ketogenic diet for five to six days out of the week. But, for one to two days you will consume most of your calories in low fat, high carbohydrate foods.
The purpose of this is to utilize anabolic hormones like insulin to gain muscle and to replenish your glycogen storage to lift heavier weights.
But wouldn’t consuming large amounts of carbohydrates kick you out of ketosis?
Yes, but you’re strategically knocking yourself out of ketosis so that your training sessions for the rest of the week are enhanced.
The beauty of cyclical ketogenic dieting is, you receive an increase in athletic performance by consuming carbohydrates for one to two days (usually on the weekends) while still receiving the benefits of ketosis the rest of the week.
The Key to Enhanced Anabolic Hormones
Anabolic hormones, also known as growth hormones are directly responsible for the amount of muscle you build and fat you melt off.
Many bodybuilders and athletes incorporate low fat, high carbohydrate diets (LFHC) because carbs are known as the more effective muscle building energy source. But science has shown time and time again that dietary fats are important for optimal hormone production like testosterone.
Research shows that diets containing less than 20% of calories in fats can inhibit testosterone production when compared to diets that have 40% of calories or more in dietary fats[*].
One of the biggest benefits to the cyclical ketogenic diet is the increased production of muscle building hormones including insulin-like growth factor 1 (IGF-1), testosterone and growth hormone.
The Relationship Between Insulin and Muscle Building Hormones
Insulin is a hormone that has had a negative rep in terms of health longevity. But when it comes to building muscle, insulin plays a huge role. It is secreted by the pancreas when carbohydrates are incorporated into your diet.
Insulin is responsible for taking blood glucose, storing it as glycogen in the muscles and liver and also inhibiting fat as a source of energy. When you have low insulin levels, glucose is no longer used by the body and it begins to use fat for fuel. This is why restricting carbohydrates induces ketosis.
So wouldn’t you be missing out on insulins muscle building benefits by going keto?
Not if you’re following the cyclical ketogenic diet correctly.
Once or twice a week during your carb load phase, your insulin will spike which transports amino acids into the muscle tissue and also refills your body’s depleted muscle glycogen storages.
Muscle glycogen is similar to a gas tank. They fill up with carbohydrates but are emptied when we restrict them. The downside to large amounts of carbohydrates is, when the glycogen “tank” is full, it is converted into triglycerides and gets stored as fat. This is why many people who are on a “dirty bulk” experience fat gain simultaneously.
What is the point of filling up your glycogen tank if any excess is going to get stored as fat?
Muscle glycogen drastically improves your strength and lifts in the gym. When they are full, your body has more energy for lifting.
Adopting a cyclical ketogenic diet will give you the muscle building and strength benefits you receive from carbohydrates. Then after your carb load phase — by following a SKD on your non carb load phase — your body depletes any excess glycogen storage and starts burning fat for fuel via ketosis.
This whole process allows you to build muscle while ensuring you don’t store fat like you would on a normal, high carbohydrate diet.
Growth Hormone Is Elevated When Insulin is Low
Anyone in the bodybuilding realm knows that growth hormone is a crucial hormone in building muscle.
- Increased muscle strength and mass
- Improved fat loss
- Stronger bones
- Reduced risk of cardiovascular disease
The downside is, research suggests that elevated insulin levels contribute to a reduction in the release of growth hormone.
One study showed that in obese subjects, the amount of growth hormone released was directly affected by the amount of insulin present. The study concluded that lower levels of insulin produced larger levels of growth hormone and vice versa[*].
On a CKD, you’re only spiking your insulin during your carb load phase — decreasing growth hormone for one to two days out of the week — followed by a restriction in carbs which will help lower your insulin and increase growth hormone for the remainder of the week.
Unlike LFHC diets, a cyclical ketogenic diet can help you build muscle, drop fat while still maintaining peak levels of hormonal production.
If you have followed a standard ketogenic diet in the past, adopting a cyclical ketogenic diet shouldn’t require much effort. It’s important to follow a strict ketogenic diet when you aren’t in the carb load phase. This is to ensure your body doesn’t get confused as to which fuel source to use for energy.
The ability for your body to switch from one fuel source to another — from fats to carbs and vice versa — improves and becomes more efficient with exercise, fasting and eating the right foods. This mechanism is called metabolic flexibility.
The Standard Ketogenic Diet Phase
The “ketogenic” phase of CKD is identical to the standard ketogenic diet.
For five to six days out of the week, you will need to consume 5-10% of calories in carbohydrates, 15-25% in protein, and 65-75% in healthy fats.
Here is a list of foods to eat during the standard ketogenic diet phase:
- Fatty meats
- Grass-fed butter
- Coconut oil
- Olive oil
- MCT oil
Remember, the goal during the SKD phase is to keep your insulin levels low, deplete your glycogen storages to prevent fat gain, and increase growth hormone.
So are carbohydrates required post-workout during the ketogenic phase if you’re trying to build muscle?
Against popular opinion, carbohydrates are not required post-workout. During the ketogenic phase of the CKD, consuming post-workout carbohydrates will only end up decreasing your body’s growth hormone production and hinder your progress.
One study in particular split healthy young men into 3 separate groups each consuming different amounts of carbs and protein. Each group consumed .3g of protein per kg of bodyweight. The only difference was the amount of carbohydrates they consumed[*].
- Group one ate just protein with no carbs
- Group two ate protein with .15g of carbs per kg of bodyweight
- Group three ate protein with .60g of carbs per kg of bodyweight
Each group trained for one hour and was given a combination of protein and carbs each hour for a total of six hours after training. Protein synthesis was measured after the six hours.
The results showed that consuming carbohydrates post-workout did not increase protein synthesis whatsoever[*].
This study further proves that you do not need any carbohydrates post-workout during the ketogenic phase of the cyclical ketogenic diet.
The Carb Load Phase
The CKD guideline for your carb days should consist of consuming 70% of your calories in carbohydrates, 15-20% in protein, and 5-10% in fats.
This is almost the exact opposite of your standard ketogenic diet (SKD) days. It’s important to keep your fat intake low on your carb days so your body is properly utilizing the additional carbohydrates to build muscle and stored as glycogen instead of body fat.
Many people who have followed a strict low carb, high fat ketogenic diet have reported thyroid and adrenal problems. This is because when you’re in ketosis, your body is mimicking what it feels like to be in an extremely fasted state. It then starts taking energy away from certain processes in the body that isn’t crucial for survival.
Strategically incorporating the carb load phase can negate any adverse effects you might have from staying in ketosis (or fasted) for too long.
The carb load phase can help restore your adrenals and revitalize your thyroid.
Eating any carbohydrates including candy and doughnuts is not the correct way to prime your body into a muscle building state. Many people think that following a cyclical ketogenic diet means you can get away with eating whatever you want during the weekends.
This is not the right way to build muscle on the CKD.
Consuming simple carbohydrates during your carb up days can lead to inflammation as well as poor insulin and blood sugar levels.
You need to be consuming healthy, complex carbohydrates rather than quick, simple carbohydrates.
Complex carbohydrates take longer to digest in the body. They are made up of sugar molecules that are bound together in long, complex chains. This means they provide you with steady increases in blood sugar that won’t create an unhealthy insulin spike.
Additionally, complex carbohydrates contain more vitamins and minerals compared to simple carbohydrates. Simple carbohydrates are often known as “empty calories” because they don’t contain any vitamins, minerals or fiber[*].
Here is a list of complex carbohydrates you should eat during your carb load phase:
- Sweet potatoes
- White or brown rice
- 100% whole wheat bread
- 100% whole wheat pasta
- Butternut squash
- Multigrain cereal
Simple carbohydrates you should avoid at all costs during your carb up phase include:
- White bread
- Fruit juice
- White flour
- Agave nectar
- Corn syrup
Make sure to check the nutrition label for any hidden sugars before you purchase any packaged foods. There are several apparent “health foods” on the market that contain added sugars like the ones listed above.
After your carb days, your main goal should be to deplete your body’s glycogen storages that you have accumulated from your carb days. Getting rid of the excess glucose will help you get back into ketosis and start burning fats for energy again.
Here is an effective way to get back into ketosis after your carb load phase:
- Day 1: Utilize intermittent fasting by not eating anything until dinner time. For dinner, eat a standard ketogenic diet meal with minimal carbohydrate intake.
- Day 2: Perform heavy compound lifts or high intensity interval training on an empty stomach. Continue to eat meals that are ketogenic-friendly.
- Day 3: Upon waking, perform a high intensity interval training workout in a fasted state. Continue to eat low carb, high fat ketogenic meals afterwards.
The longer you have followed a ketogenic diet and the harder you train, the quicker your body will get back into ketosis after a carb up. This means your body has healthier metabolic flexibility.
Since the goal of the cyclical ketogenic diet is to deplete glycogen storages, you must have a strict workout regimen in place that involves compound lifts such as squats, bench press, deadlifts and shoulder press.
Here is an example of an effective CKD workout regimen:
- Monday — Lower body workout. Perform four sets of 12 reps of squats, leg press, and lunges. Finish it off with lower body accessory work such as leg curls and calves.
- Tuesday — Upper body workout. Perform four sets of 12 reps of bench press, rows, and shoulder press. Finish it off with accessory lifts like such as face pulls, bicep curls, and tricep extensions.
- Wednesday — High intensity interval training like sprints, rowing or cycling.
- Thursday — Full body split. Perform five sets of five reps of heavy compound lifts including; deadlifts, barbell rows, incline bench press and weighted pull-ups.
- Friday — Rest
- Saturday — Full body high rep workout or high intensity interval training.
- Sunday — Low intensity cardio
This workout regimen is designed so your body depletes the glycogen storages you accumulate from your carb load days.
Incorporate Intermittent Fasting Into Your Cyclical Ketogenic Diet
Intermittent fasting (IF) has become a highly popular nutrition trend and aids the ketogenic diet greatly.
IF is a meal timing protocol where you cycle between periods of fasting and eating.
Utilizing intermittent fasting can drastically improve your body’s metabolic flexibility. This means if you fast after your carb load phase, you can speed up the time it takes for your body to start burning ketones again for fuel.
High Intensity Exercise Speeds Up Ketosis
High intensity interval training (HIIT) is any workout regimen that requires you to perform very extreme bursts of exercise followed by a short recovery period.
Examples of HIIT include:
- Sprinting for 30 seconds followed by a 30 second rest. Repeat 10 times
- Cycling for one minute as fast as possible followed by a one minute rest. Repeat 10 times.
- Rowing for 30 seconds as hard as you can followed by a one minute rest. Repeat 15 times.
Incorporating HIIT with your cyclical ketogenic diet will speed up the rate in which your body depletes its glycogen storages and starts using ketones again (after your carb load phase). This is because HIIT requires you to use fast-twitch muscle fibers instead of slow-twitch.
Fast-twitch muscle fibers require more energy to perform so when you have a maxed out glycogen tank, performing anaerobic exercise like HIIT is a highly effective way to deplete your storages quickly.
Once the glycogen storages are depleted, your body switches back to using ketones for energy.
Adopt a Cyclical Ketogenic Diet for Optimal Aesthetic Improvement
The cyclical ketogenic diet is not for the beginner dieter. It takes a certain amount of dieting experience, nutrition timing and discipline to truly experience the benefits of CKD.
Building muscle and gaining strength on a standard ketogenic diet may seem close to impossible due to chronically low levels of insulin and low glycogen storages.
Conversely, following a low fat, high carbohydrate diet can blunt your body’s crucial muscle building hormones like testosterone and growth hormone. This is why many people experience fat gain while bulking on a high carb diet.
The cyclical ketogenic diet takes the best of both worlds and utilizes carbohydrates for its muscle building benefits while at the same time, maintaining optimal hormone production with the help of ketosis.
If you have successfully followed a ketogenic diet in the past but noticed a decrease in athletic performance, implementing a cyclical ketogenic diet can drastically help you build muscle while still maintaining a lean physique.