Over the past few years, intermittent fasting has grown in popularity among health and weight loss communities. The same can be said for the ketogenic diet — more and more people are becoming attracted to this low-carb diet lifestyle because its promising health benefits. So is there such a thing as intermittent fasting keto-style?
As it turns out, the two often go hand-in-hand. The keto diet and intermittent fasting compliment each other very well.
Partaking in a short fast can help you enter ketosis initially, or help you get back into ketosis after a carb-laden meal. Plus, both the keto diet and intermittent fasting have similar health benefits.
Below, you’ll learn exactly what intermittent fasting is, its associated health benefits, and how it can be a great supplement to the keto diet.
Basics of Intermittent Fasting
In the most basic terms, intermittent fasting consists of going without food for a specific period of time. Every night, you fast while you sleep, going without food between dinnertime and breakfast the next morning — a period of roughly 12 hours.
When people participate in intermittent fasting, they typically prolong this period to 14, 16, or even 24 hours. On fasting days, you will only drink water, black coffee, or tea, not consuming any calories.
There are different types of intermittent fasting, but the most common involves only eating within a certain window of time — commonly referred to as your “eating window” — each day. For example, you might only eat between 12 p.m. and 6 p.m. each day. This would put your fasting window at 18 hours, causing your intermittent fasting ratio to be 18/6.
A fasting window can be contracted or expanded, depending on your goals and how comfortable you are with fasting. For someone just starting out, it’s recommended to start with simply skipping a meal (like breakfast).
Those more comfortable with intermittent fasting might expand their fasting window to a full 24 hours. Others will extend their fasting time frame even further, partaking in 48-hour fasts or alternate-day fasting.
Benefits of Fasting on the Keto Diet
There’s a wide overlap between intermittent fasting and the keto diet. Below, you’ll learn about the health benefits of intermittent fasting, and why it’s so beneficial on a low-carb diet.
Fasting Can Help You Enter Ketosis Sooner
Here’s how intermittent fasting works: When your body is in a fasted state, it starts burning your fat stores for energy. Sound familiar? That’s because a very similar process happens when you enter ketosis.
When you deplete your body of glucose, your body will start burning fat stores, or ketones, for energy. But here’s the thing — when given the choice, your body will choose glucose as its primary fuel source, every time. Therefore, you have to restrict your carb intake considerably to switch to burn ketones (the metabolic process known as ketosis).
When following a low carb, high-fat diet is not enough, intermittent fasting can help you enter ketosis. This will help deplete your glycogen stores (stored glucose) faster, thereby helping you enter a ketogenic state[*].
It Can Help You Avoid Keto Flu
If you’re completely new to the keto diet, intermittent fasting can help you avoid some common uncomfortable side effects such as the keto flu. These uncomfortable side effects typically occur when your body transitions to a fat-burning state.
Now the question is, how can intermittent fasting negate keto flu?
Since keto flu commonly takes place when you’re getting into ketosis (and goes away once your metabolic switch flips, so to speak), the quicker you get into ketosis, the less likely you’ll suffer from negative side effects. Since a short fast can help you get into ketosis faster, it can help reduce the likelihood you’ll suffer from keto flu.
Fasting Can Help You Lose Weight Faster
One of the biggest reasons people turn to intermittent fasting is for fat loss. Fasting can help you break through weight loss plateaus in a few different ways[*]:
- Your body can only comfortably take in a certain amount of calories at once, so limiting your intake window naturally limits total daily caloric intake.
- The smaller eating window helps eliminate unnecessary snacking, especially late at night.
- Eating a high-fat keto diet and being in ketosis reduces appetite and increases satiety levels[*]. It’s much easier to do intermittent fasting when this is the case, versus a diet full of carby foods that just increase cravings and snacking.
If you started the keto diet to help you lose weight, supplementing with intermittent fasting can help you reach your goals.
It Can Help Stabilize Your Blood Sugar
One of the main benefits of the keto diet is that it helps balance your insulin levels. When you eliminate carbs and sugar from your diet, you also eliminate the blood sugar spikes that often follow eating these foods.
If you’re looking to control your blood sugar levels, experimenting with intermittent fasting could help. In various studies, intermittent fasts were shown to help balance blood glucose levels[*].
This can help improve insulin sensitivity and prevent insulin resistance, which can thereby reduce your chances of developing heart disease or type 2 diabetes[*].
It Can Help Your Body Heal Itself
Intermittent fasting activates something called autophagy, a phenomenon which helps your body heal itself. It helps the body essentially “clean house,” removing harmful and toxic compounds and recycling damaged proteins.
Autophagy can be triggered during periods of starvation (intermittent fasting) or when carbohydrates are severely restricted (the keto diet)[*]. This could help your body heal itself of cancer or other chronic diseases.
Intermittent Fasting Keto Tips
If you’re just beginning to experiment with intermittent fasting, the transition can be tricky. If you want to start combining intermittent fasting with your ketogenic diet, here are some tips for success:
Make Sure You Eat Enough
When you go long periods without food, you may naturally eat fewer calories throughout the day. To avoid vitamin deficiencies or metabolic issues, be sure your calorie intake is at a healthy level.
Severe calorie restriction can result in a loss of muscle mass, depleted energy levels, and other unhealthy side effects.
Also, don’t use short fasts as an excuse to eat sugary, carb-laden foods or go through periods of overeating. Instead, focus on eating nutrient-dense foods during your eating window, as outlined in your keto meal plan.
Eat plenty of healthy fats from foods like avocado, coconut oil, and MCT oil; high-quality proteins from animal and plant-based sources; and plenty of leafy green vegetables.
Measure Your Ketone Levels
Even though fasting can really help you stay in ketosis, it’s still important to make sure you aren’t eating too many carbs or doing anything else to kick you out of ketosis. Track your ketone levels often to make sure you’re actually in ketosis.
Start With a Moderate Approach
If you’re new to fasting, it’s probably not a good idea to dive straight into a 24-hour fast. Instead, start small — try skipping breakfast, then slowly extend your fasting window. If you’re not experiencing any negative side effects, you can eventually transition to trying a full day fast.
Intermittent Fasting Keto: It Can Work for You When Done Right
Intermittent fasting is a practice where you go without food for a designated time period. Since intermittent fasting naturally depletes your glycogen stores, it’s a great complement to a keto diet.
Start with a moderate approach. Skip breakfast, then slowly extend your fasting window to 14, 16, or even a full 24-hour window. Intermittent fasts come with similar health benefits to the keto diet, including loss of body fat, balanced blood sugar levels, and helping you enter ketosis faster.
Intermittent fasting can be a tricky process, so be sure to give your body an adjustment period. Eat nutritious foods as outlined in your keto diet plan, track your ketone levels, and eat enough calories.
If you’re unsure of where to start, check out this beginner’s guide on the seven different types of intermittent fasting to decide which approach is best for you.