How Do I Start a Keto Diet with Intermittent Fasting?

minute read | Last update: Jan 28th2024

This article is backed by studies and reviewed by a certified dietician.

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Combining a Keto diet with intermittent fasting can accelerate the results for your health. Still, questions like does it really help, and how do I start a keto diet with intermittent fasting put you in a fix?

You can start a keto diet with intermittent fasting by maintaining the ketogenic nutrient ratio even while fasting. That is, you need to keep a count of the carbs, protein, and fat you eat during the breaks of your fasts. Plus, you got to thoroughly consider your fasting windows. The most recommended duration is the 16-8 window where you eat for 8 hours and fast for the other 16.

If you successfully pull off a ketogenic diet with intermittent fasting, you can get on a speed keto. That means your body will transit into a state of ketosis quickly and also maintain with ease.

Do you wish to learn all about how to follow a keto diet with intermittent fasting and reap the benefits? Dive into this guide and get the detailed plan of maintaining the keto along with intermittent fasting.

Following the keto diet and intermittent fasting together

Combining the ketogenic diet is all about following its regular principles, along with your decided set of fasting windows. You still got to consume nutrients in the ratio of 60-30-10, along with not eating or fasting for a few hours in the day.

How many hours should you fast on keto? Before getting to the recommended fasting window, here are the different intermittent fasting options you have while on keto:

Skip A Meal

One of the easiest and the best ways to start intermittent fasting is gradually getting into it. If you stop eating all of a sudden, your body will not be able to bear the hunger pangs. What actually is a relatively easy process will become a challenging one for you.

Skipping meals allows your body to get into the habit of not eating slowly. You can start by postponing one of your meals (for example, lunch) by an hour or more every day.

This way, you can soon get to the time where you can skip it with your body favoring the decision. You got to be on the same team!

Fasting Windows

Another excellent and one of the most common ways to go about intermittent fasting is dividing your day into eating and not eating. This is the fasting window concept you may have heard about quite often.

You can decide upon windows like 12-12, 14-8, 18-6, etc.

Here, you can eat only for one segment and fast or just drink water (or tea) during the other. For example, if you opt for the 14-8 window, you will fast for a continuous 14-hour period and eat only during the 8-hour period.

Fasting while Working Out

For those of you fitness enthusiasts, you need not ditch your high-level workout for intermittent fasting on keto. Continue your workout sessions as usual, but change the meal types and timings to suit the new routine.

Some of the rules include consuming more carbs on workout days and more fats on rest days. That is, while still maintaining the keto macronutrient ratio and maximum carb threshold (50g). Additionally, you got to make your post-workout meal the largest one and manage others accordingly.

Alternate Fasting Days

This approach allows you to eat for a day and fast another, making it relatively challenging for beginners. You must follow this type of fasting only when your body is habitual to fasting for a few hours at least.

Another way of going about alternate fasting is restricting your calories on alternate days instead of fasting completely.

This is a comparatively easier approach.

Having decided about following the two regimens together, you are now confused about what to do next. How do you really follow the ketogenic diet with intermittent fasting simultaneously?

4 Simple Steps to intermittent fasting on Keto

Step 1: Start with keto first.

One of the most important facts that you must remember is you cannot start keto and intermittent fasting at the same time. You got to first get your body accustomed to the keto diet, letting it enter the ketogenic state.

You need to ensure your body is using ketones (converted from fats) instead of glucose for energy. This will occur only when you are already into the low-carb keto diet for a few days. Additionally, this approach will make it easier for you to enter ketosis and maintain it.

Step 2: Intermittent fasting of shorter windows

Once your body has entered the process of ketosis (using fats for energy instead of glycogen), you will feel less hungry. This is when you can set off intermittent fasting. Nevertheless, you must not start with a large window for starters.

In a nutshell, forcing your body into fasting is not the wisest idea. You got to take baby steps by reducing your diet, skipping meals, and then expanding the fasting window. One of the best options for beginners is starting with an 18-6 window where you fast for 6 hours.

Step 3: Maintain the correct nutrient ratio

Another aspect that you need to ensure while merging the two health plans is maintaining the required macros. Even when you are fasting, if you do not keep a check on your carb intake, your body will move out of ketosis.

Besides, make sure to consume enough fats so your body can produce the required energy. These things are essential for you to maintain your daily routine without feeling weak and hungry.

Step 4: Extend the fasting windows

Follow this process of fasting only for a few hours for the initial days. Extend your fasting window to 8 hours after 3-4 days, followed by 10, 12, and so on. This way, you can increase the windows until you reach your desired option.

Throughout this process, bear in mind to go slow, especially when your body does not accept the change.

How will the keto diet and intermittent fasting affect your body?

Following a keto diet is all about making your body fat-adept. That is, shift from glucose (obtained from carbs) to ketones (chemicals obtained from fats). This state, known as nutritional ketosis, allows your body to use up fats from the bloodstream, resulting in weight loss.

When you start fasting, your body is already accustomed to using up the stored fats for energy. As a result, you will not feel lethargic or depressed, and your energy levels will remain normal. This allows you to easily extend your fast, though you must still go about it slowly.

In a nutshell, both these regimens enhance your body metabolism—the process of breaking food or fats into energy. On the contrary, keto breaks down the fat you eat. Another essential aspect of combining these two routines together is your ketone level.

Intermittent fasting boosts the process of ketosis in your body, resulting in stimulating speed keto. Moreover, following both routines at the same time will allow you to curb your hunger and feel lighter.

Potential benefits of following the keto diet and intermittent fasting

Still wondering why is the concept of intermittent fasting with keto so hyped? Well, its benefits extend more than just weight loss. From blood sugar control to improved mental and physical health, get ready for a host of health benefits!

Speed ketosis

If you have decided to get on the keto diet recently, you might as well go a notch higher. Go ahead and top it with intermittent fasting, and you will get on speed keto. Never heard about it before? It is a fancy term used for the ultimate combination of the keto diet and intermittent fasting.

Yes, that is everything we are discussing here. Speed keto kicks your body into ketosis relatively faster than the traditional keto, shifting its energy source from carbs to fats. Additionally, it gives you all the benefits that a regular keto diet would.

Weight loss

Yes, keto too stimulates weight loss, but when combined with intermittent fasting, it just gets a whole lot better. Intermittent fasting goes a step further and instills the process of thermogenesis, i.e., the heat production. Resultantly, your body burns up those stubborn stored fats at a faster pace.

There's more to it. When your body is habitual to the shorter eating windows, you will feel automatically feel fuller and less hungry. This will keep you from reaching out for those mid-meal snacks.


Another indispensable benefit of intermittent fasting and keto is autophagy—the process of cells disposing of themselves. Sounds like a dangerous thing, right? Well, it is the opposite. This process is all about regenerating the damaged sections of a cell and removing the toxic ones.

As a result, autophagy helps skin rejuvenation, strengthens the immunity system, slows aging, and more. So, how does it occur? Autophagy can come into action through different dietary regimens like fasting, restricting protein, or carbohydrates. Thus, the keto diet and intermittent fasting have so many health benefits.

Controlled blood sugar

Both intermittent fasting and the keto diet exhibit positive effects on blood sugar control. They improve the insulin sensitivity of your cells and help reverse the effects of type 2 diabetes.


So, would they prove to be as valuable when followed together?

When combined, the keto diet and intermittent fasting will act synergistically, aiding blood sugar control. So, for those of you depending on medicines and struggling with this major problem, you might as well try this option.

Improved brain health

Did you know intermittent fasting and the ketogenic diet can help boost your focus? Your brain requires a lot of energy to process thoughts and carry out actions. You may be wondering that if you fast, you will not have the energy to do mental tasks, but it's the opposite.

Fats are actually the most energy-efficient fuel source of your body. So, when you follow this two-in-one dietary plan, rest assured of mental clarity and enhanced focus. Your body has a huge storage of energy that your brain can consume without any issues.

Enhanced fitness levels

Do you think you cannot maintain your high-level workout routine once you adopt this dietary regimen? You can actually exercise and build upon muscle mass when following keto and intermittent fasting.

According to a study, you can work out even better while fasting. Plus, it aids preserve muscle mass and enhances gains. Moreover, when you maintain a nutrient-rich diet on this regimen, your body will break down the nutrients quickly after a fasted workout.

Risks of the keto diet and intermittent fasting

So far, you are well-versed with all the potential benefits of this remarkable blend of keto and fasting. But what about its downsides? Well, the good news is it does not have any severe setbacks.

That being said, individuals with certain special conditions might face a few side effects. Here is all you got to know about the risks of the ketogenic diet and intermittent fasting.

  • If you do not adhere to the keto diet's required macros, you can suffer from nutrient deficiencies or muscle mass loss.
  • Following this collected regimen can get challenging over the longer term, and thus, unsustainable.
  • You are vulnerable to the keto flu—a condition wherein you have flu-like symptoms and lethargy due to ketosis.
  • Following the one-meal-a-day plan does not suffice the required macros.
  • Your body will require some time to get accustomed to the new diet.
  • Potential side effects include headache, dizziness, constipation, etc.

Pro tip: Here’s how to get rid of the keto flu.

Apart from the above mentioned, this diet may not be healthy for individuals with the following conditions, currently or previously:

  • Binge eating disorder
  • Underweight individuals
  • Pregnant women or those who are breastfeeding
  • Individuals under 18

Note: You must get in touch with your doctor if you are already on medication, suffer from diabetes, or other health conditions.

Keto-friendly foods to eat on feeding windows

Are you ready to indulge in this superb combination? Walk through the keto-friendly foods you can eat during your fast windows and stock up in advance!

  • Bone broth
  • Scrambled eggs
  • Salad made of leafy greens
  • Fruits like avocados, blueberries, cherries, melon, and other berries.
  • Nuts like almonds, macadamia nuts, cashews, chia seeds, etc.
  • Chicken, beef, pork, etc.
  • Keto-friendly smoothies
  • Tea, coffee, etc.
  • Healthy oils like olive, coconut, etc.
  • Tuna, shrimp, and other seafood.
  • Other vegetables: tomatoes, broccoli, zucchini, olives, etc.
  • Unflavored yogurt
  • Cream and cheese (mozzarella, cheddar, etc.)

Overall, you can eat all types of keto-friendly items that you otherwise eat. However, you need to ensure that you do not overeat, balance your macros well, and opt for easy-to-digest foods. This will allow you to maintain your keto diet and intermittent fasting in a harmonious way!

Foods and drinks to avoid on feeding windows

Though you can eat all the keto-friendly foods during your feeding windows, you must still avoid some. These may disrupt your diet by raising the total calories, bad fats, etc.

  • Fast foods
  • All forms of alcohol
  • Foods and beverages containing fructose, artificial sweeteners, colors, and other preservatives.
  • Packaged juice.
  • Low-fat or condensed milk
  • Hotdogs, jerky, salami, etc.
  • Grains
  • Sweets and candies

Fast-friendly liquids

One of the best things about intermittent fasting is you can consume zero-calorie liquids throughout the day. Let water be your best friend!

  • Water: Springwater, sparkling, and mineral water.
  • Apple cider vinegar
  • Tea like black, oolong, green, and other herbal teas.
  • Black coffee with no sweeteners.
  • MCT oils
  • Supplements like pure collagen, electrolytes, fish oil, etc.

A day on the keto diet with intermittent fasting

Do you think planning the proper diet can be overwhelming? You need not worry. Just go about your regular keto-friendly meals while maintaining the fasting periods, of course!

Take a breath, and walk through this fantastic keto diet and intermittent fasting routine. You can follow it completely or just refer to it and customize your diet plans with your favorite foods.

Note: This is an example of the 16-8 hour window where you fast for 16 hours with an 8-hour eating window between 1:00 pm to 9:00 pm.

  • 7:00 am – Wake up and drink water (Hi, best friend!)
  • 10:00 am – Drink black tea/ green tea/ black coffee –unsweetened
  • 1:00 pm – 8 ounces of chicken breast along with a salad of leafy greens topped with oil and cheese.
  • 4:00 pm – Its snack time. Have some almonds (or other nuts) and berries
  • 7:00 pm – 8 ounces of fish with greens like asparagus, string beans, sprouts, etc.
  • 9:00 pm – You can still have dessert! Add fresh cream to blueberries for the last course.

Cannot find your favorites on the list? Just swap these items with the ones you like while ensuring the nutrient ratio of each meal.

Tips for the keto diet and intermittent fasting

Are you excited about putting it into action? Well, why won't you! This amazing diet combination has so many benefits in store, you cannot just ignore!

Keeping all the excitement aside, following this routine requires the utmost patience, especially for the initial days. These tips got you covered with everything you must take into consideration during the diet.

Mealtime matters

The most important thing to bear in mind while following this routine is your meal timings. Knowing the exact timings will let you stay on track, allowing your body to benefit from this regimen. Jot down the time of your daily meals, be it large or small. Plus, make sure to eat similar meals (nutrient composition) every day at the same time.

Passing hunger

Hunger pangs are expected during the first phase of your keto and fasting plan. However, you can go about it by delaying your daily meals until you reach the desired fast window. Once you get accustomed to the routine, your body itself will not feel hungry, as it helps curb your appetite.

Do not binge

One of the biggest mistakes that multiple individuals do is binge eat during the short, fast windows. It practically ruins the whole point of following such a challenging diet. Make sure to eat only a limited number of meals that are well in accordance with the keto requirements.

Stay busy

Staying busy is downright the best way to maintain a keto diet with intermittent fasting seamlessly. It will not only help you forget about the hunger pangs but also allow time to pass quickly.

Drink water

You must always keep your body hydrated. Do this by eating a whole lot of juicy veggies during your feeding windows, drink water, and other fast-friendly beverages. Water becomes your best friend for multiple reasons. It helps curb hunger, keeps you busy, and prevents your mouth from getting dry without having to eat anything.


Do you think you know everything about the excellent keto diet and intermittent fasting combination?


Well, that's a perfect yes.


This guide talks all about how you can start the keto diet with intermittent fasting. From the body processes to benefits and application, you are covered.

Following the two trendiest health regimens might help you tremendously, but only if you follow them well. A few quintessential points include sticking to the macronutrient content, maintaining the fasting windows, and eating only keto-friendly foods. Remember, start fasting only after your body is already in ketosis.

Now that you are a keto genius, why not go and crack that keto diet with intermittent fasting? Stock up food, decide your window, create a dietary plan, and get to it now!


Can you combine the keto diet and intermittent fasting?

Yes, you can combine the keto diet with intermittent fasting by following both simultaneously. That means you will have to choose a fasting window that you will spend without eating (or drinking anything) except fast-friendly beverages. Plus, during your feeding windows, you can eat only keto-friendly food items in limited quantities.

That being said, you need to make sure to start with intermittent fasting only after your body is in ketosis. This will help your body to get accustomed to the new regime.

What is the right fasting window on keto?

The correct fasting window on keto depends upon your body state. If you have already started with keto and your body is in ketosis, you can easily pick any of the windows. However, you must only begin from small and increase gradually.

The best options for fasting windows are 16-8 and 14-10, where you fast for 16 or 14 hours. You can eat for the rest of the time.

Can you lose weight with intermittent fasting and the keto diet?

Yes, the keto diet and intermittent fasting are both weight-loss routines and hold the potential of aiding weight loss.

When you follow the keto diet, your carb consumption will reduce, making your body use fats to extract energy. That is because usually, your body uses the glycogen present in carbs to generate energy. Using these fats instead of them helps lose the stored fats.

When you add intermittent fasting to this regimen, your ketosis process runs at a faster pace. That is what is called speed ketosis or intermittent fasting with keto.

What can you eat while following intermittent fasting on keto?

First of all, you must know that intermittent fasting prevents you from eating all types of foods during the fasting window. You can only drink a few beverages like water, black tea and coffee, and other unsweetened drinks.

When it comes to eating during the feeding window, you have an extensive range of options. You can choose any of the keto meals and snacks, as far as they do not increase the required nutrient ratio. These include avocados, bone broth, green leaf veggies, chicken, tuna, eggs, etc.

About the author

The Authentic Keto Team is here to bring you health tips that help you with losing weight fast. We focus on a clean keto diet for beginners because we believe that is the easiest and most simple way to healthy eating. Our keto weight loss tips will not only bring you into ketosis fast but will also help you to improve your mental health, sleep problems, and wellness.

- Our goal is to make keto success easy. -

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