Intermittent Fasting with Keto

Like most people I’ve spent a ton of time at home, practicing social distancing and doing my part in preventing the spread of the virus. While at home I’ve posted a few Keto friendly desserts, those are fun and useful tools to make Keto more of a lifestyle and less of a diet… by now you know that I don’t like the word “DIET”. Click here to read more on desserts and my thoughts on the word “Diet”. The problem with writing about desserts is that I’m eating all of those desserts as I buy or make them at home…Aye yi yi, say it isn’t so Keto Bandeeto!

Another tool that I employ is Intermittent Fasting. In an earlier post titled “Keto on the Go” I outline when I use intermittent fasting, but here and now let’s take a deeper dive into what is Intermittent fasting, what are the benefits and how do you employ IF (Intermittent Fasting), and how does it relate to a Ketogenic Lifestyle

What is Intermittent Fasting?

According to Wikipedia: Intermittent fasting, also known as intermittent energy restriction, is an umbrella term for various meal timing schedules that cycle between voluntary fasting (or reduced caloric intake) and non-fasting over a given period.

Three methods of intermittent fasting are alternate-day fasting, periodic fasting, and daily time-restricted feeding. Intermittent fasting may be similar to a calorie restriction diet. Although being studied in the 21st century as a practice to possibly reduce the risk of diet-related diseases, intermittent fasting is also regarded as a fad.

The science concerning intermittent fasting is contested. The American Heart Association (AHA) states that intermittent fasting may produce weight loss, reduce insulin resistance, and lower the risk of cardiometabolic diseases, although its long-term sustainability is unknown. The US National Institute on Aging (NIA) recommends against intermittent fasting because of uncertainties about its effectiveness and safety, particularly for the elderly. A 2019 review concluded that in humans, intermittent-fasting interventions may help with obesity, insulin resistance, dyslipidemia, hypertension, and inflammation.

Forms of intermittent fasting exist in various religious practices, including Hinduism, Islam, Orthodox Christian faith, Jainism, and Buddhism.


Types of Intermittent Fasting


Time Restricted (16:8)

Probably the most popular one around and the one I personally do, the 16/8 method of fasting is where you fast for 16 hours and eat for 8 hours. There are variations of this like 18:6 or 20:4

This is the best one to start off with. You give yourself a 16-hour window where you eat nothing, but you can consume drinks such as teas, coffees, water etc. Thereafter, you have an 8-hour window where you can eat 2 or 3 meals, however you like.

The easiest way to do this method is by simply skipping one meal a day. Personally, I try to skip breakfast as it’s the easiest meal for me to skip. I stop eating at 8pm, only drinking tea, water or zero calorie drink mixes like Crystal Light or 4C Green tea mix. In the morning it’s black coffee or nothing at all until noon… when you’re on the run and working you’d be surprised how easy this can be.

Alternate Day (24hrs)

Alternate Day Fasting (ADF) is what it sounds like. You go for a whole day without eating solid foods. Just like the 16/8 method you can drink non-caloric beverages the whole time. Typically, I’ll eat an early dinner, say by 6pm and then fast until dinner the following day. This is most likely not the best strategy if you’re new to intermittent fasting. You should ease your way into it and start off with the 16/8 method instead. Like building new muscle, you should look to start small and work your way up to this. Alternate day fasting promotes weight loss, but is linked to hunger, which can be counter-productive to losing weight. I’m certainly ready for dinner by the end of the following day, but here’s the thing… after going 24 hours without eating it’s not like the hunger is cumulative, you’re not hungry enough to eat double portions in fact you’ll find that a regular or sensible meal is satisfying and satiating. Have you ever heard someone say that their stomachs shrunk? That’s the feeling you’ll have. Talk to you Doctor before trying this method of more extreme intermittent fasting.

Prolonged Fasting (24-72 hrs)

This is not for beginners and certainly not for the faint of heart and of course you’ll want to consult your physician (psychiatrist, priest, shaman anyone that will talk you out of this…LOL). This is as simple as it sounds, one common method is to stop after dinner on the first day and begin eating again at dinnertime on the third. Once again, you can still drink zero-calorie fluids, such as water, black coffee, and tea, during the fasting period. It’s vital to drink plenty of fluids to prevent dehydration, which is one of the major potential complications of longer fasts. Afterward, it’s important to gradually reintroduce food. That way, you avoid overstimulating your gut, which may lead to bloating, nausea, and diarrhea. Your first meal post-fast should be a light snack, such as a handful or two of almonds. This would be followed by a small meal one or two hours later. I’ve worked my way up to a 48-hour fast… not sure if I will go much further than that. It’s also important to note that prolonged fasts are not something that you want to do too often, 2 – 4 times a year

Benefits of Fasting

Let’s take a look at this in increments as they begin to happen…

  • After 4-8 hours – Blood sugars fall, food has left the stomach and your no longer producing insulin (the fat storing hormone)
  • After 12 hours – Food that’s been consumed has been burned, the digestive system goes to sleep and the body begins to heal. Human growth hormone levels (HGH) begin to rise.
  • At 16 hours – Ketosis (wait what?) the fat burning begins, glucose has been depleted and the body begins burning fat for fuel
  • At 18 hours the body’s ability to burn fat grows exponentially…you’re in the sweet spot, HGH levels are high
  • After 20 hours – Your body is a fat burning machine and in heavy Ketosis, especially for those that are following a low carb lifestyle
  • 24 hour mark – Autophagy begins! Autophagy: is one of the greatest benefits of fasting. It is a cellular self-cleansing process that breaks down and recycles damaged molecules and cells. When fasting this rate increases dramatically, which then allows for your body to rejuvenate and restore itself to a better or newer ‘version’. Essentially the body eats itself starting at the weak cells
  • 36 hour – Autophagy increases by 300%
  • 48 hour – Autophagy increases 30% more, Immune system reset and regeneration starts….this is as far as I’ve gotten

Custom Keto Diet

Intermittent fasting and Keto

When we are fasting, we are technically in ketosis because as we fast for more than 12 – 16 hours our body becomes depleted of glycogen and our body is forced to use our fat stores as fuel to keep our body running. Getting into ketosis is what the Ketogenic diet is all about. We know that by consuming a high fat, moderate protein and low to no carb diet our body eventually becomes depleted of glycogen and when that happens our body is forced to switch to fat (fat adapted)  and use it as the main source of energy….this is the magic of the Keto diet, your body is burning the fat you have stored for energy.  When you combine that with intermittent fasting you will double the amount of fat you will burn in a given day. 

Following a low carb or Keto lifestyle, you’re most likely already in Ketosis, mix in intermittent fasting and you “dial up” the fat burning and get into heavy ketosis that much quicker. Conversely as you break your fast, by staying low carb, you extend the the heavy fat burning mode that you’ve forced your body into. Make no mistake… this is a powerful strategy for fat loss!

Final thoughts

Intermittent fasting with Keto can be a powerful tool and there are a ton of benefits (some of which we’ve just outlined) from fasting… but tread carefully. Ease in to intermittent fasting, listen to your body not the stopwatch and make sure that you stay thoroughly hydrated, add a vitamin supplement if you don’t already take a multivitamin… and most importantly use good judgment.

Have you dabbled with fasting? What’s been your experience? Leave a comment…

Stay strong… stay healthy… stay safe!

20 thoughts on “Intermittent Fasting with Keto”

  1. I don’t like eating breakfast, but I do drink a lot of water in the morning – it does create a more profound benefit to your body if you don’t eat anything at the same time.

    1. Simon,
      Agreed. Giving your body time, to simply heal itself and do it’s thing is beneficial. Ancient man didn’t have food readily available and weren’t living on 3 squares a day, they needed to hunt and gather food.
      Thanks for the read and the kind words


    1. I don’t think that skipping one meal over another makes a huge difference. The key is to work this around what you would be more comfortable with. I’m most comfortable eating dinner, one because we like to sit down to dinner as a family…. then skip breakfast because by 7 am when I would typically have breakfast before work I already have a head of steam… it’s been approximately 12 hours since my last meal… a cup of black coffee will take the edge off and then it’s off to work where I’m not focusing on food anyway… next thing you know it’s noon and I’ve fasted 17-18 hours… easy peasy

  2. I pretty much do the time restricted option. I’m quite lucky that I have a fast metabolism.

    I think fasting is a great option for anyone, let alone anyone trying to lose weight. I find it keeps the body optimised. Although the thought of some people not eating for that period of time is a scary thought for them.

    How much coffee do you consume till you start eating?

    1. Fast metabolism?
      Beware it slows down as you get older. I agree there are some distinct benefits to fasting. Look at at the religions that incorporate fasting in some fashion or another. The body needs some time to recover. Usually it’s one large black coffee, like a venti. Hot or cold. Usually on the run in the AM… right now, not so much. Afternoons during a longer fast on occasion… too much coffee makes me jittery
      Thanks for engaging!


  3. I really enjoyed reading your post. I have been doing intermediate fasting for a while now so when I saw that this blog post was about intermediate fasting, I knew I was going to like it. I usually fast for about 16 hours. Sometimes I fast for 20 hours and sometimes 12 hours. I have seen a lot of benefits from it. I notice that I have more energy during the day and do not feel sluggish. Thank you for the post!

    1. Scott,
      Thanks for the read and the kind words. Intermittent fasting has helped me get over the wall so to speak at times in my weight loss journey. Have you tried any prolonged fasts (24+ hours?)


  4. Hello Bob-what really good information on what is really happening inside our bodies when we choose to fast. And breaking it down at what certain amount of hours, this or that is happening, ie “dial up fat burning”. That’s what we all want. How often do you work out? Do you work out when fasting? Thanks for the education on Keto Fasting.

    1. Nancy,
      The funny thing is I really don’t work out much especially now during the lock down. I try to remain active by logging 10,000 steps daily Nd I’m currently working on a push challenge to do 100 push ups all at once. There are marked advantages to working out in a fasted state. – Check out this video


  5. Intermittent fasting is really good to know about here and thank you so much for sharing this post out here. To be honest, learning a lot more about intermittent fasting here is good to know and I am delighted I came across this post. To be honest, I would love to get involved with it more and have a routine. I think I can work with the 16:8 intermittent fasting. Thats a lot better for me. Thank you so much

    1. Ella,

      incorporate intermittent fasting to your normal routine at your own pace,  I think you’ll be pleasantly surprised.  Thanks for the read and the kind words

  6. Hi! I have also spent all this time at home and recently I have been researching about fasting. I like your post and I’m glad I found it.

    I think I’ll go with the option of restricting myself through specific eating windows. I’m new at fasting and I think this guarantees the highest possibilities of success. Starting with a 18:6 window wouldn’t be too aggressive on the walls of my stomach?

    1. Ann, 

      Let your body be your guide, there’s nothing wrong with 16:8. if you can stop eating by 7pm (no snacking) and have water, black coffee or tea in the morning and eat lunch at 1pm you’ll accomplish the 18:6 and I think you’ll find that it’s not that difficult.


  7. There are indeed  benefits of Intermittent fasting to the body. 

    Personally I  have been practicing the time restricted fasting and it’s really been beneficial to me, I have really reduced in my body size. I try as much as I can not to take anything in the morning except water which I noticed was very good,then I start eating after 8 to 9 hours. So for me the time restricted fasting is the best. 

    1. It’s surprising how easy it is to do. As a society we are programmed to eat the 3 meals per day. At times it seems like we eat because we’re expected to and not because we are hungry. Breakfast is the easiest meal for me to skip because mornings are usually hectic and there’s a time deadline to meet for work or the kids… I typically don’t wake up hungry either, how about you?


  8. Hi Bob,

    I’m please to read your post.  As the value and importance of Keto is something I want to learn more about.  Also the three methods of intermittent fasting of alternate-day fasting, periodic fasting, and daily time-restricted feeding.  These are areas I’ve wanted to learn about to some time now, particularly the daily time-restricted feeding (someone I know swears by it). and I’m pleased to read that you do that and its the easiest to start with.

    I am very lean (very low body fat), have always had high metabolism, and not interested in burning fat or losing weight.  If anything I would like to gain some muscle.  Will there still be benefits for me in doing the 16:8 fasting?  I don’t think I could do 24 hours of fasting, my metabolism burns through food and I feel I need more.

    Thank you

    1. John, 

      There are some distinct advantages to fasting for anyone… even those who are lean and don’t necessarily want the fat burning benefits for example the increased mental acuity, autophagy, reducing leptin levels, increasing testosterone, reduce blood pressure and cholesterol levels. I’m not a doctor and I can’t even say that I recently slept at a Holiday inn… but I would try 16:8 a few times a week and let your body guide you.

      Thanks for read!


  9. I’ve been doing intermittent fasting for ages, mainly in the form of skipping breakfast. Recently I’ve been skipping lunch as well as I’ve been working from home due to the pandemic. I find it a lot easier to just stop eating all together than to try and eat small meals throughout the day, I always end up taking seconds once I start eating. So intermittent fasting is definitely great for losing fat and controlling weight. But if I’m trying to gain strength and a bit of weight, I actually find that breakfast really helps with recovery. Do you have any thoughts/experiences with this? The same goes with keto, I feel like it severely limits the intensity and volume of strength training.

    1. Jukka,
      I haven’t been in the situation where I needed to actually gain weight… that might be my superpower, the ability to gain weight without really trying. To your point however, you can gain muscle while on Keto & fasting check this video out by Thomas DeLauer. This guy is really dialed in to KETO and IF
      Thanks for reading


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