Keto Diet & Intermittent Fasting 101 – The Definitive Guide

Combining diet methods was once a huge discussion. Now that it has been put into action and studies have concluded positive results, more are questioning which are the most effective to combine. 

The ketogenic diet is becoming more and more popular. As is intermittent fasting. Especially for weight loss and excelled fat burning. Both are extremely popular in the diet industry across the world, with millions parking in each one separately year on year. 

Intermittent fasting exceeds the keto diet in popularity with being the top Google searched and tested method in 2019. 

They both benefit other health conditions from heart disease to neurological conditions. Although both are safe diets alone, many wonder if they are safe to combine. 

Both diets share a similar theme which is restriction. Keto restricts certain foods and intermittent fasting restricts when you eat. That may make you question two things. Is it possible to combine the keto diet with intermittent fasting? If so, are there extra benefits? It is possible to combine both diets and attain all benefits that they offer.

Today our aim is to help you understand the diets, the benefits and the ins and outs of combining the diets:

What is The Keto Diet?

The keto diet is not a new diet to the market. It dates over 100 years ago to the 1920’s. “Keto” stands for ketogenic. Keto is a shortened version of the original name.

The ketogenic diet was introduced many years ago as an epilepsy treatment. This was the then original keto diet. Epileptic patients found that carbohydrates made their symptoms worse. As it increased the risk of developing epilepsy, patients changed their diet to a 4:1 ratio of fat to protein and carbs. 90% of the keto diet calories were from fat. Then 6% from protein and 4% from carbs.

The keto diet is now often known for its many other health benefits. The ketogenic diet is often known for its weight loss and heart health benefits. As well as reducing cholesterol, treating brain disorders and lowering blood sugar levels. 

The keto diet limits carbohydrate intake, which allows room for more fats and proteins. Which makes the ketogenic diet very beneficial for quick weight loss. Fat and protein are btoh incredible sources energy. Both improve energy endurance. They are also the reason for the diet being very beneficial for your health. 

Click here to learn more about Keto Diet

With the knowledge of the keto diet in mind, let’s take a look into what intermittent fasting is:

What is Intermittent Fasting?

Many people assume that fasting is starvation. That assumption is incorrect. Starvation is an involuntary uncontrolled period without food. Whereas fasting is voluntary and controlled. Fasting, especially intermittent fasting, is for health, religious and spiritual reasons. 

Intermittent fasting is an eating pattern method with cycled mealtimes. The method is often shortened to “IF”. It does not dictate which foods to eat and avoid. Instead, it gives you time periods of eating and not eating. The technique provides meal time cycles

Understanding how to intermittent fast is essential so that a person does not over fast. Lack of knowledge can be damaging to the body and the mind.

The fasting technique is often used to aid weight loss. The food cycles allow your body to use and burn fat quicker. This helps speed up the process of weight loss and improves body fat mass and BMI. Not only does it help with weight management, IF offers many more health benefits. Fasting can reduce the risk of suffering heart conditions. It can also improve brain function and lifespan. It can also slow the progression of medical conditions such as diabetes, cancer and aging.

Many people who contemplate fasting worry that it can cause health risks. Many worry that the cons may outweigh the pros. In fact, intermittent fasting offers more health benefits than it does risks. 

For the majority, fasting is nourishing and safe for the body. It is a detoxifying ritual that the body benefits from, more than it does from eating too much or too often. The human body can withstand periods of fasting and lack of food. Ever since times of war, plagues and epidemics humans have had to practice fasting and periods of no food at all. 

Throughout history, fasting was a useful way for humans to ration food. This rationing inhibited supplies from being completely used up. Today, fasting is a healthy and natural way for the body to detoxify and regenerate. 

Due to its history, scientists have a new found understanding of intermittent fasting. They acknowledge that it is sustainable by the human body. Investigations have looked into its health benefits and risks. More of which, we will share later. It is important to be aware that intermittent fasting can pose benefits and risks. Yet, risks are very limited.

Click here to learn more about Intermittent fasting

Now, you may wondering exactly how to combine the two diets:

How To Combine The Two Diets

Combining the two diets is fairly simple. Once you have mastered and acknowledge how to successfully partake in the keto diet, the next step is integrating intermittent fasting.

The main part of this diet is understanding what foods you can and cannot eat. Intermittent fasting is not so much as diet, it just restricts the times at which you eat. But, the keto diet does involve food limitations. The reduction in carbohydrates is heavily substituted with healthy fats and proteins. There is a fairly strict, but extensive, food list to stick by for the keto diet.

The ketogenic diet involves a person getting 80 percent of calories from fat. The rest comes from protein (20%) and carbohydrates (10%). 

Fat is your friend as opposed to your enemy on this diet. The substitution of fat for carbs encourages the body to burn fat over carbs/glucose. Excelled fat burning is known as ketosis, which is an increase in metabolic state. Ketosis and fat burning is ideal for weight loss. 

To successfully consume a ketogenic diet you must eat lots of lean protein, low carb foods and high fat everything. The daily fat intake is quite high for this particular diet. Fat you consume should always be healthy fats. These are best for the body and are those that promote the health benefits.

Then, once you have planned your keto diet, it is time to schedule in the intermittent fasting. The timings and food cycles will depend on which method you have chosen. For example, if you have chosen the 16:8 time restricted method, you should align your keto meals in the 8 hour eating window. It is as simple as that. 

Combining the two diets is pretty simple, with the right knowledge and guidance. You simply need to eat keto based meals during the eating windows. Then you will successfully be on a keto intermittent fasting diet. 

Here are the foods ideal for the ketogenic diet:

  • Unprocessed low carb meats: beef, venison, pork
  • Poultry: chicken and turkey
  • Fish and seafood: fatty fishes are best – salmon, mackerel, herring
  • Eggs: all types of eggs are good cooked in olive oil
  • Low carb vegetables: leafy greens, broccoli, cauliflower, kale, spinach, tomatoes, mushrooms, peppers, cabbage and zucchini
  • Salt, pepper, herbs and spices: thyme, paprika, oregano
  • High fat dairy: hard cheese, creams, yoghurts. Avoid high sugar dairy products such as ice creams and milks
  • Water, tea, coffee: any zero calorie drink
  • Berries: red berries are lowest in sugar and therefore carbs
  • Avocados: a great healthy fat source
  • Nuts: macadamia, pecan, almond and brazil nuts 
  • Seeds: pumpkin seeds, flaxseed, chia seeds and hemp seeds
  • Natural fats: olive oil, avocado oil, coconut oil, sesame oil
  • High fat sauces: avoid sugary sauces. Best options include bearnaise sauce, garlic sauce, lemon butter sauce and no sugar mayonnaise

For more information about the foods to eat on keto and why they are beneficial for your health, read more here on our Foods To Eat On The Keto Diet.

The keto diet offers a plentiful list with a large variety of foods to enjoy. Ensure your meals are full of fat and protein to stick to the keto diet requirements. This also means that meals should be low in carbs. This will help curb hunger and control appetite for the hours you fast.

Most foods to avoid for the keto diet are obvious. But, there are a few which may surprise you.

  • Breaded meats, poultry and fish: crumbed meats and fish are high in carbohydrate
  • Cold cuts: cold cuts of meats contain added sugar
  • Milky drinks: coffees, hot chocolates and teas
  • Low fat yoghurts: fat is your friend on keto. Always choose the high fat options
  • Bread and baked goods: carbohydrates are a food to avoid on the keto diet. This category includes baked goods such as donuts, crackers and rolls
  • Rice: cooked rice contains starch which is carbohydrates
  • Pasta: spaghetti and noodles are high in carbohydrates, which is not ideal for the keto diet
  • Starchy vegetables: potatoes, sweet potatoes, peas, corn, pumpkin, squash
  • Alcoholic beverages: beer, mixed drinks and wines. They are all high in sugar
  • Sweetened beverages: soda and juice are high in sugar. They are okay in small amounts
  • Candy : sugar, ice cream, syrups and chocolate. Instead enjoy fruits, such as berries. Or no sugar/milk teas to please your cravings
  • Fruits: citrus fruits, grapes, bananas and pineapples
  • High carb sauces: barbeque sauce, sugary salad dressings, ketchup, honey mustard and dipping sauces
  • Unhealthy fats: vegetable oils, corn oil, margarine. Swap these for olive oil, avocado oil or coconut oil to consume healthier and more natural fats
  • Processed foods: ready made meals, fast food and packaged food 
  • Diet foods: any that contain added preservatives or sweeteners

Use these lists as a guide for shopping when starting the keto intermittent fasting diet. Consuming the right foods will help you stay on track and achieve the best results the keto diet and intermittent fasting has to offer. Consuming enough fats and protein is key for the keto diet and will help sustain you through fasting periods. 

To understand more about what benefits this combination diet can offer, read on:

Benefits of Combining The Two Diets

There are a multitude of health benefits a person can attain from the diets by themselves. Most benefits are similar. Yet, there are a few benefits that are unique to the eating/diet method. Thus, combining the two diets maximises the benefits a person can achieve. 

The main benefits they share are reduced risk of heart disease, increased weight loss and the possibility to prevent cancers.

Here’s more on the benefits of combining the two diets:

Possibility to reach ketosis quicker

The keto diet promotes its ability to reach ketosis. This is where the body runs out of glucose and turns to fat as a fuel source. This encourages fat burning. Which is what makes the diet very popular for those seeking weight loss. 

Intermittent fasting (IF) helps the body reach ketosis quicker. When the body is fasting, the energy balance switches from carbs to fat. Studies show that this is due to the body running low on glucose. Intermittent fasting promotes lowering insulin and glycogen levels. This is the exact same premise as the keto diet. Hence, fasting alongside the vegan ketogenic diet allows the body to reach ketosis quicker. 

Once the body hits ketosis, the diet will be easier to sustain. Ketosis helps control hunger, which makes the participant eat less and only when they need to. Not only will this make the diet easier, it will excel weight loss.

Increased fat loss

The quicker the body reaches ketosis, the quicker the body will burn fat. 

All dieting methods limit certain nutrients. Dietary limitations often result in fat loss. This is due to them increasing metabolism. The increase in metabolic rate results in fat burning. Metabolism promotes thermogenesis, which is a process that utilizes stubborn stored fat. 

The keto diet does promote fat burning due to decrease in carbohydrate intake. 

Then, intermittent fasting is a method which is popular for its fat burning abilities. Many studies reveal that the 16:8 IF method is most effective for fat burning. Participants of 16:8 can see 14% more fat loss than regular dieting. 

Better mental clarity

When the body adapts to the ketogenic diet, it will manage to live off ketones. This is down to the fat fuel burning used as a key source of energy for the brain and the body. Fat is the most sustainable source of energy. The brain uses a lot of energy. Thus, is very beneficial for ultimate brain functioning. 

The reason for the combination diet being better for mental clarity is due to ketosis. A normal diet involves high carbohydrates. Which means it relies on carbs for regular energy. Thus, when the body runs low on carbs, it will suffer and feel weak. 

But, if the body adapts to the lack of carbs and runs off of fat fuel, it will always have a source of energy. This means your brain can run all the time instead of being energy deprived.

More energy

Evidence shows that intermittent fasting methods can increase energy endurance. The same goes for the ketogenic diet. This is due to the calorie and nutrient reductions because of timed eating periods. Athletes notice longer energy endurance during fasting periods. Their performance improves due to this.

To consume all essential nutrients, it is best to take supplements. This further will improve energy levels and inhibit nutrient deficiencies.

Slower muscle loss

Studies reveal that intermittent fasting promotes slower muscle loss. Thus, helps preserve muscle mass. IF methods that allow a person to achieve autophagy increases muscle maintenance. Autophagy increases the human growth hormones (HGH), which promotes muscle preservation. 

This is beneficial alongside the keto diet, to increase fat loss and muscle gain. This is achievable due to the higher protein intake which the keto part of the diet requires. 

A participant must ensure to eat the right amount of nutrients to sustain the keto diet. Which will make intermittent fasting safe and beneficial for muscle mass. This includes the correct intake of carbs, protein and healthy fats on a daily basis. This will maximise results and inhibit nutrient deficiencies.

There are many upsides to combining the diets. Practicing the diets as one offers a multitude of incredible health benefits. 

With the correct knowledge of foods to eat whilst intermittent fasting on the keto diet and the benefits it offers, here are a few top tips to achieve the best results:

Tips For The Best Results

To maximise results of the keto diet with intermittent fasting, there are a few simple things you can do:

Avoid breaking your fast with carbs

Avoiding carbs for your first meal is key. The best thing to break a fast are healthy low fat foods and proteins. This will help you inhibit a spike in blood sugar levels. You should always be well hydrated before breaking your fast too, to help balance your blood sugar levels.

Avoid snacking

For those seeking weight loss, snacks should be avoided as much as possible. Snacks are usually unnecessary foods that you eat due to boredom or in between meals to keep you going. Excessive calories can cause weight gain. 

If you eat enough keto balanced meals, which include fats and proteins, it should sustain you long enough. Until your next meal at least. If you do decide to snack, choose some of the healthy keto snack options above. This includes nuts, eggs, high fat yoghurts, fruits and vegetables.

Eat well balanced meals

Along the same lines of well balanced meals, this is ideal for maintaining weight and achieving the best results. Meals packed with high fat and lean protein foods will help you sustain a healthy diet as well as reap maximum benefits. Remember that limiting carb intake is key for the keto diet part. It also helps you achieve ketosis quicker, which encourages excelled fat burning and weight loss.

Well balanced meals full of essential nutrients will also inhibit nutrient deficiencies. 

Use supplements if necessary

If you do worry about nutrient deficiencies, supplements are a good idea. They will help you attain all the essential nutrients, vitamins and minerals your body needs in order to stay healthy and well functioning. It will also maximise results as your body will not be deprived of any essential components. 

Maintain a regular exercise routine

Keto and intermittent fasting benefits can be excelled with regular exercise. The keto diet helps intermittent fasters reach ketosis quicker. With exercise, this will maximise the fat burning benefit even more.

Keep a schedule

Having a well thought out plan is key to help you stay on track. Once your plan is finalised, keeping track of your diet and exercise can help you sustain the diet long term. Noting your favourite meals, best times to exercise and your progress will encourage you to keep going.

Try the most popular/effective method

The most popular method is 16/8. Otherwise known as the timed restricted eating routine. This involves 16 hours of fasting and 8 hours of eating. During the eating window you should consume balanced keto meals. Either 2 large meals or 3 smaller meals. Avoid snacking to maximise results and to maintain a strong digestive system. Overeating can cause your digestive system and your metabolism to slow down. This can cause stomach issues and weight gain. 

Try the most extreme method

If you want to try the most extreme intermittent fasting method whilst on the keto diet, you can do so. This is known as 23/1 intermittent fasting keto, or otherwise OMAD. This involves eating one meal a day. This allows you to reap the benefits for 23 hours of the day. The remaining one hour is when you eat. As you are also on the keto diet here, you should make the meals keto appropriate. So, a large high fat and high protein meal would be ideal. This could include low-starch vegetables and lean meats topped with seeds, high fat sauces and dairy. A small amount of carbs is key to ensure you do eat some carbs. This can be found in fruit, nut butters and sauces. 

The number one benefit of the OMAD fast is resilience. Studies show that the long fasting period of 23 hours stresses your cells into being stronger. This is known as hormesis. It will maximise all benefits of the keto intermittent fasting diet. Such as maximised reduction in heart disease, anti-aging, increased weight loss and metabolism. The results are incredible. Yet, this method should be done with caution and the right knowledge.

Try these top tips for yourself and see the benefits maximise. Be sure to stick to keto based meals during eating hours to successfully achieve this diet. 

Some may be wondering if intermittent fasting can work without keto. Here is more:

Can Intermittent Fasting Work Without Keto?

Intermittent fasting can indeed work without keto. It has been used as an eating style for centuries for weight loss and other benefits. 

Following a fasting routine with keto will still allow you to reap its benefits.

The reason being for combining the two diets is to maximise benefits. Also, to reach ketosis quicker which encourages excelled fat burning and use of fat storage. 

Many weigh up intermittent fasting vs keto. Both have become extremely popular for weight loss. Some use them for the other health benefits. And, both are very effective. 

To put it simply, both of these will work effectively for whatever you wish to try them for. Whether that be weight loss or improving heart health. There is not enough evidence to suggest one is better than the other. It all depends how much work you put into the diet and also on the individual themself. 

For most, intermittent fasting may be easier to sustain longer term due it being more of a lifestyle change as opposed to a dietary change. Again, it all depends on the individual.

Like all diets, there are some ups and downs. For this combination diet, they are as follows:

Pros and Cons of Practicing Both Diets Together

Like any diet, combination or independent, there comes pros and cons. These may not be the case for everyone. But, these are the positives and negatives that may occur for most participants. 

It is important to cover the pros and cons so that people can be aware if combining ketogenic and intermittent fasting is beneficial or right for them. 

Maximises weight loss benefitsMay cause increased side effects from both diets – fatigue, weakness, irritability
Can improve mental clarity and brain functionCan be difficult to sustain long term
Increases energy levelsMay not suit everyone’s lifestyle
Helps maintain fat loss and muscle mass
Can reach ketosis quicker
Decreased appetite and increased hunger control
Reduces the risk of heart disease

With those pros and cons in mind, you may have some more questions. Below are answers to the top most asked questions about combining the keto diet with intermittent fasting:


What is a good breakfast for fasting on the keto diet?

A typical keto intermittent fasting breakfast should include high fat, lean protein and no carbs. Any type of eggs are ideal for a keto diet. Low carb vegetables are a good choice too. This includes breakfast vegetables like mushrooms, tomatoes, kale, peppers and spinach.

Low carb options are the best to break a fast as it will inhibit a spike in blood sugar levels.

You can also have a look on our Best Keto Breakfast Casserole Recipes

Which has more benefits, keto diet or intermittent fasting?

Both have very similar health benefits. The main reason for combining the two is for maximised benefits and also to reach ketosis faster. 

Neither is more beneficial than the other. That is up to the individual and their health needs to decide. But, some may find intermittent fasting more achievable and sustainable as it does not restrict any dietary nutrients. Those who struggle to cut carbs may find the keto diet a challenge.

How long should you intermittent fasting on keto?

Research suggests that whilst on keto, intermittent fasting methods should change between long and short periods. This is to ensure you do not encounter severe nutrient deficiency. To prevent this and ensure you are safe, you can take nutrient supplements alongside the diet to attain those you may be deprived or low of. 

Some may also develop refeeding syndrome. This is where the body sees a fatal shift in fluids and electrolytes due to undernourishment. These shifts can cause detrimental effects to your health and hormones. 

What can I drink whilst intermittent fasting on keto?

The keto diet actually promotes the consumption of the same drinks intermittent fasting requires. This includes no calorie drinks such as water, black coffee or tea. 

Can you have cheat days on intermittent fasting with keto?

If your key goal is to lose weight, a cheat day on this diet will not inhibit progress. According to research, it suggests that you should stick to keto friendly foods to prevent blood sugar spikes and reversing ketosis.

So long as your chosen intermittent fasting method allows a day of food, then it is fine.

Can I exercise during fasting on keto?

It is safe to exercise whilst fasting, even if choosing the extended 24 hour fast. As long as your body has enough energy and hydration, it will cope if you exercise often. 

Fasted cardiovascular exercise linked with excelled fat burning. As are keto and intermittent fasting. It is a good technique to use if your goal is to burn fat.

What breaks an intermittent fast?

Anything that contains calories will break an intermittent fast. This can be a calorie drink or any food. 

When you do break the fast, a small low carbohydrate meal is best to prevent your blood sugar from spiking.

All of this knowledge is everything you need for starting the keto diet and integrating intermittent fasting. For our final thoughts, here’s more:


It is safe to say that the keto diet with intermittent fasting is definitely achievable and sustainable for most. The only dangers it poses are mild side effects and health impacts for those who are at risk. 

To successfully maximise and reap the health benefits of this combination diet, you should consume keto friendly meals. Remember to keep your carb intake low and your fat and protein intake high. High fat and lean protein meals will not only sustain your energy, it will help control appetite and increase results. 

The key to this is planning and tracking. Setting out a schedule to follow the right intermittent fasting method for you will help you control your diet. Then, tracking will allow you to note results and encourage you to sustain the diet in order to continue reaping the benefits.

If you have any more concerns, questions or feedback, please share them with us. Use this as your guide for the keto intermittent fasting diet. 

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