The cyclical ketogenic diet (CKD) is an advanced dietary strategy that combines the fat-burning benefits of ketosis with scheduled carb-loading phases. It offers a flexible approach to the traditional ketogenic lifestyle by strategically incorporating periods of higher carbohydrate intake. This makes it particularly appealing for athletes and active individuals seeking to optimize their performance while maintaining the advantages of ketosis.
Understanding the Cyclical Ketogenic Diet
The cyclical ketogenic diet follows a specific pattern: 5-6 days of standard ketogenic eating followed by 1-2 days of higher carbohydrate consumption. During the ketogenic phase, followers maintain the traditional keto macronutrient ratio of high fat (70-75%), moderate protein (20-25%), and very low carbohydrates (5-10%). During the carb-loading phase, also known as the refeeding period, carbohydrate intake increases significantly while fat intake decreases. This cycle aims to replenish muscle glycogen stores while maintaining the metabolic flexibility developed through ketosis.
Standard Protocol
A typical CKD schedule includes:
- Monday through Friday: Standard ketogenic diet (20-50g carbs)
- Saturday and Sunday: Higher carb intake (400-600g carbs)
- Maintain protein intake throughout the week
- Adjust fat intake inversely with carbs
Benefits of Cyclical Ketogenic Eating
Athletes and bodybuilders often find the cyclical ketogenic diet particularly beneficial because it allows for:
- Improved muscle glycogen replenishment
- Better strength and power output during high-intensity workouts
- Enhanced muscle recovery and growth
- Maintained metabolic flexibility
Strategic carb cycling can help optimize various hormones, including:
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- Leptin levels for improved metabolic function
- Thyroid hormone production
- Testosterone levels
- Cortisol regulation
The cyclical approach offers several lifestyle advantages:
- More dietary freedom during carb-up periods
- Reduced social restrictions around eating
- Better long-term adherence potential
- Improved psychological relationship with food
Implementing a Cyclical Ketogenic Diet
Training Considerations
To maximize the benefits of CKD, consider:
- Scheduling intense workouts during carb-loading phases
- Performing glycogen-depleting exercises before carb-ups
- Maintaining regular resistance training
- Adjusting workout intensity based on energy levels
Who Should Consider Cyclical Keto?
The cyclical ketogenic diet is most appropriate for:
- Experienced keto dieters
- Athletes and bodybuilders
- Active individuals with regular high-intensity training
- Those who have mastered standard ketogenic eating
Keto Cycling: How Does It Work?
Keto cycling involves following the keto diet for a certain amount of time and then taking a day (or more) off. It doesn't have a strict definition. Some people choose to have five or six days on keto followed by a day or two off. Others will do keto for 10 to 12 days followed by three to four days off.
The Science Behind Glycogen Stores
It’s important to think about your glycogen stores, which are your body’s supply of stored carbohydrates, as a gas tank. “As long as we don’t let that tank dip over, we can deplete it pretty quickly again and get back into ketosis,” she says. “But as soon as we go beyond that three or four days [off keto], our tanks flood and you start to store some of that glucose as fat, and it becomes very difficult to deplete that tank again and get back into ketosis.”
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Carb Quality Matters
On those higher-carb days, it is recommended to stick to whole foods with low amounts of sugar rather than going on a full-blown carb binge. Foods like fruit, sweet potatoes, and whole grains - all considered complex carbs - rather than white bread and sweets will make it easier for the body to re-adapt to ketosis. Consider what time of day you’re eating these carbs, too. It’s best to eat carbs (again, opt for those complex choices) in the daytime when you're most active (if that's true for you) as opposed nighttime.
When to Start Keto Cycling
It is advised not to jump right into keto cycling. “I would definitely not try keto cycling until you’re about two to three months into your keto diet,” she says. “That's because you need to make sure your body is fat adapted so that it can get back into ketosis easily.” In her practice, it has been noticed that if the body is used to being in ketosis, it’ll snap back more quickly after eating a carb-heavy meal than if a person is new to keto. It is not encouraged to do keto cycling unless the individual has been following a clean keto diet, which calls for sourcing the healthiest version of keto-approved foods, such as grass-fed meat and whole foods, for at least three months and has a regular and rigorous exercise plan. This should allow them to eat higher carbs without seeing weight gain or intense cravings.
Exercise After High-Carb Days
It is important to follow up a high-carb day with vigorous exercise the next morning. The idea is to force the body to burn the glycogen you took in so it can get back to working on fat burn.
Potential Health Benefits and Risks of Keto Cycling on the Ketogenic Diet
Because keto cycling is so new, no studies have examined the benefits and risks yet. Cycling in and out of ketosis - eating carbs then not eating carbs - might be dangerous. “If you eat a high-fat diet one day (like what is recommended in the keto diet) and then go back to eating carbs the next, I think a person could be in danger of storing much of that consumed fat, which can result in high triglycerides and cholesterol,” she says. She explains the body may not have time to convert fat to energy, so it may stick with using the carbs for energy and storing the fat.
Limited Research
There isn't much research on keto cycling, though one small study was published in September 2020 in Nutrients. The researchers found that keto cycling resulted in an amount of weight loss in young, healthy men similar to that engendered by a nutritious diet that cut 500 calories per day. The weight loss for the keto cyclers, however, was from a combination of decreased body fat, water, and lean body mass, whereas the other dieters primarily lost body fat.
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Anecdotal Evidence
Some anecdotal evidence suggests that people are more likely to stick with keto if they incorporate cycling. You could also end up losing more weight if you stick with the diet for a longer period than you otherwise would have.
Benefits for Athletes
Some people believe elite athletes benefit from keto cycling because their bodies use extra carbohydrates as energy to power through difficult workouts and races. “For an avid athlete, timing carbohydrate intake based on intensity and type of activity can have performance benefits,” Devine says.
Research has shown that the strict keto diet impairs exercise performance. One study found keto hurts athletic performance more than a high-carbohydrate diet or one that includes periods of high carbs and low carbs (which is similar to keto cycling). It seems the body uses high-quality carbs as exercise fuel. “Running on glucose (carbs) during intense strength training workouts can be beneficial,” Devine says. Another study, published in Nutrition Today in January 2018, found that carbohydrates are the only macronutrient that can be broken down quickly enough for the body to use during high-intensity exercise.
The Challenges Associated With Keto Cycling
Because it’s best to try keto cycling after your body has already adjusted to ketosis, you likely won’t be able to avoid the challenges of starting keto, such as the keto flu and while keto cycling can be helpful for people who crave higher-carb items from time to time, it is not for everyone.
Carb Hangover
“Anecdotally, some people who try keto cycling do find it difficult,” she says. “When you reintroduce carbohydrates back into your diet - and this is more about refined carbs, I’m not talking about eating an apple - you don’t feel very good.” She says some people experience a so-called carb hangover - the body feels kind of bloated and inflamed, and you may develop headaches.
Overindulgence
It can also be a challenge not to overindulge on those days off the diet. “For somebody who’s been a carb addict or a sugar addict before going on the diet, all of those cravings for those sugars and those carbs come back pretty strong,” Devine says. “It’s kind of like saying, ‘I’m going to stop smoking, but I’m going to have one cigarette a month.’ Good luck. I just think it's a hard dietary approach to follow.”
Should You Try Keto Cycling?
Be careful about starting keto cycling or keto in general if you’re pregnant or nursing. It's also important to consult your primary care provider first. People with type 2 diabetes should also consult their doctor, and those with type 1 diabetes or kidney problems should avoid the diet, as should anyone with conditions related to their pancreas, liver, thyroid, or gallbladder, according to University of Chicago Medicine.
Impact on Weight Loss
If you’ve cleared the approach with your healthcare team and weight loss is your ultimate goal, know that keto cycling won’t be nearly as effective as traditional keto. “It can halt your weight loss by taking those days off because during that time you’re not going to be burning any fat and you could be putting more on,” she says. “I have seen ‘cheat days’ turn into cheat months and just backfire for the client completely. It creates a very ‘yo-yo’ approach to weight loss which can be very discouraging.” the results of keto cycling are never as dramatic as when the body is kept in a constant state of ketosis.
Long-Term Adherence
On the other hand, if you take the approach of following the keto diet most days but cycling helps you stay on course, cycling could help you stick to the keto diet longer.
Self-Control is Key
What it boils down to is this: You need to know yourself and your self-control. “If you’re able to have a higher-carb day that includes healthy carbs and be able to get back on track the next day, then it might work for you,” Devine says. “But if you’re somebody who kind of loses control when you get around sweet foods, and one doughnut means the entire case of doughnuts, you’re going to have trouble with it.”
Cyclical Keto Diet: Detailed Steps
There is no standard set of rules for a cyclical ketogenic diet. However, anyone wanting to start it should follow a standard ketogenic diet 5-6 days per week, adding 1-2 days of higher carb intake.
Standard Keto Days
During standard ketogenic days, it’s important to consume 20-50 grams of carbs per day. During this phase of the cyclical keto diet, healthy fats should deliver approximately 65-90% of your total calorie intake.
Healthy fat options include:
- Eggs
- Avocado
- Full-fat dairy products
- Low-carb nuts and seeds
- Nut butters
- Fatty meats
- MCT oil
Proteins should make up around 10-30% of your total calories, while carb intake is typically restricted to under 5%. Be sure to follow the standard keto diet 5-6 days per week.
Refeeding Days
The second phase of the cyclical keto diet involves choosing 1-2 days per week to “refeed” your glycogen stores. During refeeding days, you should consume more carbs in order to break ketosis. On refeeding days:
- Carbs should comprise 60-70% of your total calories.
- Protein should account for 15-20% of your total calories.
- Fats should deliver just 5-10% of your total calories.
Though the goal of the refeeding phase is to increase the number of carbs, carb quality also matters. Instead of relying on unhealthy sources like white bread and baked goods, you should get the majority of your carbs from healthy sources.
Some examples of nutritious, complex carbs include:
- Sweet potatoes
- Butternut squash
- Brown rice
- Oats
- Quinoa
- Whole-wheat or brown-rice pasta
- Beans and lentils
These carbs are high in vitamins, minerals and fiber, which fuel your body and keep blood sugar levels stabilized. Avoid foods and beverages high in sugar - like candy, juice, soda and cake - as they’re devoid of nutrients and lead to blood sugar irregularity, which can cause increased hunger and irritability.
Returning to Ketosis Quickly
After high-carb, refeeding days, you should consider intermittent fasting to return to ketosis more rapidly. The most common intermittent fasting method involves fasting for 16 hours of the day. High-intensity workouts on the days following refeeding are also advised in order to achieve ketosis while optimizing muscle growth.
Potential Advantages of the Cyclical Keto Diet
Research on the cyclical ketogenic diet is very limited. Still, it may provide advantages.
- May aid muscle gain: Muscle-building - or anabolic - hormones like insulin are suppressed when following very low-carb diets like the keto diet. Insulin regulates muscle growth by allowing amino acids and glucose into your muscle cells, increasing protein synthesis and decreasing protein breakdown in muscle tissue. Using the cyclical keto diet to strategically raise insulin levels on specific days could allow you to use the anabolic effects of insulin to promote muscle growth. Keep in mind that there is not enough research on this diet to prove this method’s effectiveness.
- May boost performance in athletes: Refeeding with carbohydrates may benefit elite athletes who are following very low-carb diets. One study in 29 elite race-walkers found that the athletes benefited from periodic high-carb intake - though it did not specifically test the cyclical keto diet. The study revealed that the walkers who received periodic high-carb feedings prior to training sessions experienced significant improvements in performance compared to those following a standard keto diet. The researchers concluded that athletes who periodically consumed a lot of carbs saw an improvement in performance, while those following a strict keto diet did not.
- Decreases keto-related side effects: The ketogenic diet is associated with unpleasant side effects collectively known as the keto flu. Symptoms of the keto flu include nausea, fatigue, headaches, constipation, weakness, difficulty sleeping and irritability. These symptoms emerge when your body struggles to adapt to using ketones as a primary fuel source. Cycling in carbohydrates 1-2 days per week can decrease these symptoms.
- Adds more fiber to your diet: Constipation is a common complaint among those first transitioning to a keto diet. This is because some people struggle to obtain enough fiber when eating a high-fat, very low-carb diet. Though it’s possible to consume enough fiber on a standard keto diet, transitioning to a cyclical ketogenic diet can make it much easier. During refeeding days, high-fiber carbs, such as oats, sweet potatoes, beans and quinoa, are allowed.
- Makes the keto diet easier to stick to: The keto diet is linked to various health benefits, such as weight loss, blood sugar control and a reduced risk of heart disease. Yet, it can be difficult to follow long term. Because you must drastically reduce your carb intake to reach ketosis, many healthy - yet high-carb - foods are off limits. Using the cyclical keto diet, you can eat carb-rich foods on refeeding days, which may make the diet more sustainable in the long run. However, because there is currently little research on the cyclical keto diet, its long-term benefits are unknown.
Potential Downsides
Because research on the cyclical keto diet is limited, its side effects are largely unknown. Until studies on the diet are completed, it’s impossible to determine its full effects. Keep in mind that many people may eat too many calories on refeeding days, counteracting the weight loss benefits of the standard keto diet. Also, it should be noted that transitioning from a standard to a cyclical keto diet may result in temporary weight gain - primarily due to excess water that is retained when consuming high-carb foods. In fact, your body stores each gram of carbs in muscle with at least 3 grams of water. For those looking to boost muscle mass or improve athletic performance, it’s unknown whether the cyclical keto diet is more effective than the standard one. As research supports the standard keto diet for muscle growth and exercise performance in athletes, transitioning to a cyclical keto diet solely for those benefits may not be necessary.