keto and fasting are a match made in heaven, but what about the cyclical ketogenic diet and intermittent fasting? Do they work well? If so, then how to do it.
Cyclical Ketogenic Diet Example
Let’s cover some basics.
The cyclical ketogenic diet (CKD) is a ketogenic diet in which you cycle between low carb and high carb periods. You eat keto for a given period and then have refeeds with a lot of carbohydrates.
Here’s an example schedule.
- Initial keto-adaptation for 10-21 days
- Carb refeed for 1-2 days
- Back on low carb keto for 5-7 days
- Carb day
- Rinse and repeat
Intermittent fasting (IF) on the other hand is a way of timing your food intake. Your daily caloric consumption can be divided into two periods.
- Feeding window, during which you’re in a fed state and can eat.
- Fasting window, during which no calories are consumed and you’re in a fasted state.
There are several types of intermittent fasting that differ in terms of time constrictions and what’s eaten during the feeding window. Common IF schedules are:
- 16-hours fasted and 8-hours eating (16/8)
- The Warrior Diet (20/4)
- One Meal a Day (OMAD)
- Alternate Day Fasting, in which you fast every other day, ending up with 5 days of eating and 2 days of fasting a week (5:2)
Intermittent fasting can be done on any diet protocol and is especially effective on the cyclical ketogenic diet.
Can You Do Intermittent Fasting on the Cyclical Ketogenic Diet?
In my opinion, doing intermittent fasting in some shape or form is a lot more important for overall health and longevity. However, combining it with the ketogenic diet has greater benefits.
Keto puts you into a state of ketosis, in which you’re burning fat as your main fuel source, instead of glucose. Before that can happen, your liver glycogen stores need to be depleted, which takes about 16-24 hours. We can use this information to our advantage when doing the cyclical ketogenic diet.
Ketosis can be achieved by following a low carb ketogenic diet or by fasting for several days. Keto actually mimics the physiology of a fasted state and increases the body’s ability to burn its own stored fat for energy.
If you were to fast while on a high carb diet, or when not being keto-adapted, you would benefit from ketosis metabolism. However, you wouldn’t be as effective if you had already been following a ketogenic diet for some time. Because the body and brain wouldn’t know how to burn fat for fuel as well, you would compensate for the lack of glycogen by converting some of your muscle and organ tissue into glucose through gluconeogenesis.
Ergo, intermittent fasting on the ketogenic diet is much healthier and safer than doing it on a program that maintains a glucose burning metabolism.
How to Combine the Cyclical Ketogenic Diet and Intermittent Fasting
But on the cyclical ketogenic diet, you’re alternating between periods of using both fat and sugar for fuel. How do you IF with that?
It’s true that on your refeed days you’ll be kicked out of ketosis. Keto-adaptation creates new liver enzymes that make you prefer fat over carbs. However, it doesn’t mean that your body loses its ketogenic pathways.
Your body doesn’t want to go through random changes and seeks to maintain homeostasis – a state of inner equilibrium. Like with eating keto for one day won’t put you into ketosis, having carbs once won’t kick you out of it completely either. You’ll still know how to use fat as a primary fuel source. It’s just that you won’t be doing it while having eaten carbohydrates and will use glucose at that time instead.
Intermittent fasting works especially well post-refeed days. After you’ve filled your glycogen stores, you have access to more internal fuel and thus extending your fast will have a positive effect on re-establishing deep ketosis.
I advise having a 20-24 hour fast after you’ve had a high carb day, as to reignite your ketogenic pathways.
Cyclical Ketogenic Diet Schedule
Nevertheless, doing at least some form of intermittent fasting every day has a lot of positive benefits on health and longevity. You don’t really need to eat any more than 1-2 meals a day and should spend the majority of the 24-hour period fasted.
The golden rule is to fast for 12-18 hours every day. I myself restrict my feeding to the 16/8 window by the least. Because of the ketogenic diet, I experience virtually no hunger, zero muscle catabolism or hypoglycemia. It’s the magic of being keto-adapted.
I’ve been doing intermittent fasting for 5-6 years and started keto in 2015. Both of them are extremely good strategies for promoting vibrant health, mental wellness, physical performance, and productivity.
The Cyclical Ketogenic Diet takes it a step further by allowing more metabolic flexibility and greater social adherence. Check out my Keto Carb Cycle that includes cyclical ketogenic diet intermittent fasting, 50+ recipes with exact macronutrient ratios and a 30-day meal plan.