The cyclical ketogenic diet (CKD) is a variation of the standard ketogenic diet (SKD) that incorporates periods of higher carbohydrate consumption. This approach aims to provide the benefits of ketosis while allowing for the strategic use of carbohydrates to support athletic performance, muscle growth, and dietary adherence.
Understanding the Ketogenic Diet
The ketogenic diet is characterized by a very low carbohydrate, high-fat intake, typically consisting of 70% fat, 20% protein, and only 10% carbohydrates. By drastically reducing carbohydrate intake, the body enters a metabolic state called ketosis, where it becomes more efficient at burning fat for energy. This process also leads to the production of ketones in the liver, which can serve as an energy source for the brain.
What is the Cyclical Ketogenic Diet?
The cyclical ketogenic diet (CKD) alternates periods of ketogenic dieting with periods of high-carbohydrate consumption. It involves adhering to a standard ketogenic diet protocol for 5-6 days per week, followed by 1-2 days of higher carb consumption, often referred to as "refeeding days." These refeeding days are designed to replenish the body's depleted glycogen reserves. During refeeding days, carbohydrate intake typically comprises 60-70% of total calories, protein accounts for 15-20%, and fats make up just 5-10%.
Cyclical Keto vs. Targeted Keto
Out of the frequently used approaches, targeted ketogenic diet allows carbohydrates to be consumed immediately around exercise to sustain performance without affecting ketosis. The targeted ketogenic diet is almost exactly the same as the standard ketogenic diet, but with one difference - targeted carbohydrate intake. About 30 minutes before you train, ingest 25-50 grams of simple carbohydrates (we recommend maple syrup). If you do that and eat a standard ketogenic diet the rest of the time, you’ve just implemented the targeted ketogenic diet. Using carbohydrates in this way will give your body the sugar it needs to spare glycogen, maintain blood sugar levels, and prevent muscle breakdown while you workout. However, this may only be helpful for exercise beginners and ultra-endurance athletes.
Cyclical Keto vs. Carb Cycling
The cyclical ketogenic diet is often compared to carb cycling, but they are not the same. Carb cycling involves varying carbohydrate intake on different days of the week, typically with 4-6 days of lower carb intake and 1-3 days of higher intake. While the method is similar, carb cycling does not reduce overall carb intake drastically enough to reach ketosis.
Read also: Walnut Keto Guide
How to Implement a Cyclical Ketogenic Diet
- Standard Ketogenic Days (5-6 days/week):
- Consume 20-50 grams of carbohydrates per day.
- Obtain approximately 65-90% of total calories from healthy fats, such as eggs, avocado, full-fat dairy products, low-carb nuts and seeds, nut butters, fatty meats, and MCT oil.
- Protein should make up around 10-30% of total calories.
- Refeeding Days (1-2 days/week):
- Increase carbohydrate consumption to comprise 60-70% of total calories.
- Protein should account for 15-20% of total calories.
- Fats should deliver just 5-10% of total calories.
- Focus on consuming nutritious, complex carbohydrates from sources like sweet potatoes, butternut squash, brown rice, oats, quinoa, whole-wheat or brown-rice pasta, beans, and lentils.
- Avoid foods and beverages high in sugar, such as candy, juice, soda, and cake.
- Returning to Ketosis:
- Consider intermittent fasting after high-carb refeeding days to return to ketosis more rapidly.
- Engage in high-intensity workouts on the days following refeeding to help achieve ketosis and optimize muscle growth.
Potential Benefits of the Cyclical Ketogenic Diet
May Aid Muscle Gain: Insulin, an anabolic hormone that regulates muscle growth, is suppressed on very low-carb diets. Strategically raising insulin levels on refeeding days could potentially promote muscle growth by allowing amino acids and glucose into muscle cells, increasing protein synthesis, and decreasing protein breakdown.
May Boost Performance in Athletes: Periodic high-carb intake may benefit athletes following very low-carb diets. Studies have shown that athletes who received periodic high-carb feedings prior to training sessions experienced significant improvements in performance compared to those following a standard keto diet.
Decreases Keto-Related Side Effects: The ketogenic diet can be associated with unpleasant side effects known as the "keto flu," including nausea, fatigue, headaches, constipation, weakness, difficulty sleeping, and irritability. Cycling in carbohydrates 1-2 days per week may help reduce these symptoms.
Adds More Fiber to Your Diet: Constipation is a common complaint when first transitioning to a keto diet due to insufficient fiber intake. The cyclical ketogenic diet can make it easier to consume enough fiber by allowing high-fiber carbs like oats, sweet potatoes, beans, and quinoa on refeeding days.
Makes the Keto Diet Easier to Stick To: The cyclical keto diet may be more sustainable in the long run by allowing for the consumption of carb-rich foods on refeeding days, which can help satisfy cravings and make the diet less restrictive.
Read also: Wine on a Keto Diet
Potential Downsides and Considerations
Limited Research: Research on the cyclical ketogenic diet is limited, and its long-term effects are unknown.
Potential for Weight Gain: It's easy to consume too many calories on refeeding days, counteracting the weight loss benefits of the standard keto diet.
Temporary Weight Gain: Transitioning to a cyclical keto diet may result in temporary weight gain due to excess water retention when consuming high-carb foods.
Unknown Effectiveness for Muscle Growth and Athletic Performance: It's uncertain whether the cyclical keto diet is more effective than the standard one for boosting muscle mass or improving athletic performance.
Not Suitable for Everyone: If you’re at risk of diabetes or your body is so sensitive to carbohydrates, then it’s probably best to avoid CKD.
Read also: The Keto-Brain Fog Link
Foods to Eat and Avoid
Foods to Eat on Keto Days: Meat, fatty fish, eggs, butter, cream, cheese, nuts, seeds, healthy oils, avocados, low-carb veggies, and condiments like salt, pepper, herbs, and spices.
Foods to Eat on Refeeding Days: Sweet potatoes, butternut squash, brown rice, oats, quinoa, whole-wheat or brown-rice pasta, beans, and lentils.
Foods to Avoid: Sugary foods, grains, starches, most fruits, beans, legumes, root vegetables, tubers, low-fat or diet products, unhealthy fats, alcohol, and sugar-free diet foods.
Sample Meal Plan
Monday:* Breakfast: Veggie and egg muffins with tomatoes
- Lunch: Chicken salad with olive oil, feta cheese, olives, and a side salad
- Dinner: Salmon with asparagus cooked in butter
Tuesday:* Breakfast: Egg, tomato, basil, and spinach omelet
- Lunch: Almond milk, peanut butter, spinach, cocoa powder, and stevia milkshake with a side of sliced strawberries
- Dinner: Cheese-shell tacos with salsa
Wednesday:* Breakfast: Nut milk chia pudding topped with coconut and blackberries
- Lunch: Avocado shrimp salad
- Dinner: Pork chops with Parmesan cheese, broccoli, and salad
Thursday:* Breakfast: Omelet with avocado, salsa, peppers, onion, and spices
- Lunch: A handful of nuts and celery sticks with guacamole and salsa
- Dinner: Chicken stuffed with pesto and cream cheese, and a side of grilled zucchini
Friday (Evening Workout):* Breakfast: Sugar-free Greek, whole milk yogurt with peanut butter, cocoa powder, and berries
- Lunch: Ground beef lettuce wrap tacos with sliced bell peppers
- Dinner (Post-Workout): Begin carb-loading with higher GI whole foods, such as potatoes, yams, carrots, bananas, pineapples, raisins, and white rice.
Saturday:* Continue carb-loading throughout the day, prioritizing complex carbohydrates.
- Breakfast: Cream cheese pancakes with blueberries and a side of grilled mushrooms
- Lunch: Zucchini and beet “noodle” salad
- Dinner: White fish cooked in olive oil with kale and toasted pine nuts
Sunday:* Continue carb-loading with lower GI foods.
- Breakfast: Fried eggs with and mushrooms
- Lunch: Low carb sesame chicken and broccoli
- Dinner: Spaghetti squash Bolognese
Research Study: CKD vs. RD
To illustrate the effects of a cyclical ketogenic diet, a randomized controlled trial compared the impact of a cyclical ketogenic reduction diet (CKD) versus a nutritionally balanced reduction diet (RD) on body composition, muscle strength, and endurance performance in healthy young males undergoing regular resistance and aerobic training.
Methods: 25 healthy young males undergoing regular resistance training combined with aerobic training were randomized to CKD (n = 13) or RD (n = 12). Body composition, muscle strength and spiroergometric parameters were measured at baseline and after eight weeks of intervention.
Results: Both CKD and RD decreased body weight, body fat, and BMI. Lean body mass and body water decreased in the CKD group but did not significantly change in the RD group. Muscle strength parameters were not affected in CKD, while in the RD group, lat pull-down and leg press values increased. Similarly, endurance performance was not changed in the CKD group, while in the RD group, peak workload and peak oxygen uptake increased.
Conclusions: The data suggest that in healthy young males undergoing resistance and aerobic training, comparable weight reduction was achieved by CKD and RD. However, CKD may have a negative impact on lean body mass and endurance performance compared to RD.