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Craig on November 14, 2013

Intermittent Fasting on a Keto Diet

Ketogenic Diet Tips > Ketogenic Diet

Intermittent Fasting, or “IF”, is a relatively new craze that is used as a supplement to your diet. It revolves around the timing of your food intake, and can have some benefits in the long run. There are quite a few people misinformed on fasting, so we’ll clear that up and explain how intermittent fasting can be useful.

I want to be clear that intermittent fasting should be used for CONVENIENCE only, not for better weight loss results. There are no studies on intermittent fasting that show clear weight loss benefits, but there are studies that show health benefits. We’ll get into those later. The thing that matters the most is HITTING YOUR MACROS. If you need to learn how to calculate your macros, visit our Keto Calculator.

Restricting yourself even more than you are is pointless – it’s not worth it if it makes you unhappy. Most people are fasting because of the few health benefits and the major convenience it has for their schedules. It has been reported (no studies backing it up) that it can help you if you are in a plateu – and I am talking about a plateu of 3 weeks or longer.

There’s 2 basic terms we need to understand here: feeding, and fasting. You’re in a feeding state when you are eating your food (naturally), and you are in a fasting state when you are between your meals.

The Approach

There are a few approaches when it comes to intermittent fasting.

  • Skipped meals. This is when you skip over a meal to induce extra time of fasting. Usually people choose breakfast, but others prefer to skip lunch.
  • Eating windows. Usually this condenses your entire macronutrient intake between a 4 and 7 hour window. The rest of the time you are in a fasting state.
  • 24-48 hour cleanse. This is where you go into extended fasting periods, and do not eat for 1-2 days.
Skipping breakfast with fasting

I don’t recommend that you go straight for a 1-2 day fast, but begin by restricting yourself to certain eating windows. Typically people restrict themselves to the hours of 5pm – 11pm. People often refer to their fasting windows by numbers: 19/5 or 21/3, for example, means 19 hours of fasting and 5 hours eating or 21 hours fasting and 3 hours eating, respectively.

Once you have the hang of eating on a schedule, you can try short periods of 18-24 hour fasting. Then you can judge if intermittent fasting is for you.

Whether you decide to do it every day, once a week, or twice a week is up to you – do what makes you feel best and listen to your body.

How does it work?

Fasting can help with overeating and calorie counting
The whole point of intermittent fasting is to allow ourselves to increase the amount of food we can intake at one time. Our bodies naturally can only take in a certain amount of food at once, so we are creating a sort of limit on our calorie intake.

This is also a great method for people that overeat. I tend to see people that forget to count the snacks that they have throughout the day, and wonder why they are putting weight on.

Your body will adjust itself to fasting, and you will find yourself not as hungry as you used to be. This allows you to properly record and maintain their nutrient intakes.

In this fasting state, our bodies can break down extra fat that’s stored for the energy it needs. When we’re in ketosis, our body already mimics a fasting state, being that we have little to no glucose in our bloodstream, so we use the fats in our bodies as energy.

Intermittent fasting is using the same reasoning – instead of using the fats we are eating to gain energy, we are using our stored fat. That being said, you might think it’s great – you can just fast and lose more weight. You have to take into account that later on, you will need to eat extra fat in order to hit your daily macros (the most important thing). If you’re overeating on the fats here, you will store the excess anyway.

Like I said, it’s more for the convenience for timing, rather than the overall weight loss effects that it may have. There are other benefits, though, and we’ll discuss these too.

Benefits of Intermittent Fasting

There are a number of benefits shown that come from intermittent fasting. Some of these include blood lipid levels, longevity, cancer, and testosterone levels. The main two I want to focus on are the basis of our every day lives.


People are always saying that if you don’t utilize the importance of pre and post workout meals, you are going to be losing muscle when you work out. This isn’t necessarily true, and it is even less so when you are adapted to ketosis.

Fasting while training can lead to a number of benefits in the long run, including:

  • Higher metabolic adaptationsStudies show that your training performance will increase in the long run when you are exercising in a fasted state.
  • Improved muscle synthesis – Studies show that muscle gains are heightened when you train in a fasted state, and utilize proper nutrient intake.
  • Improved response to post-workout meals – Studies show that the speedy absorption of nutrients after a fasted workout can lead to better results.

There’s been numerous studies on fasting while training, including one on Muslim athletes during Ramadan. It concluded that there is no effect on performance in training while fasting – so you have no need to worry.

Mental Clarity

Once your body is keto-adapted, your brain can effectively run on ketones, which are derived from fat breakdown in the liver. Fat is considered one of the most energy-efficient fuels for your body to run on, and your brain is a huge consumer of energy.

Most of the high carb advocates are running a campaign on the deprivation your body gets when you do not continuously refuel on grains and fruits.

Gain focus through fasting

They want you to be carrying around an apple and a granola bar wherever you go, but the beauty with keto is that you don’t.

Even if your body is out of glycogen (which it most likely is if you’re in ketosis), it can rely on the abundance of fat from the foods you eat and stores you have. That means your powerhouse of a brain can run full power all the time. Less mental fogginess, and more focus.

As you get used to fasting, you should start to fast naturally. Meaning, only eat when you’re hungry. Don’t plan your fasting – let it happen naturally.

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