Tips For Cycling Between Primal and Keto

Consistency is key in everything we do.

Training in the gym: The most optimal workout imaginable won’t do a thing if you only get around to it once every two weeks.

Sleep: A solid 8 hours of shut eye every night beats 10 hours one night, 6 the next.

Learning a new skill: Practice for an hour each day and you’ll become a master. Spend twelve hours one time and never again, and you’ll remain a beginner.

The same is true for nutrition. A consistent, reliable way of eating—especially with a diet like keto, where extended consistency actually builds new fat-burning mitochondria and establishes habits—tends to produce the best results.

But what if you wanted to be a little less consistent? What if you wanted to cycle between Primal and keto? Is such a thing even possible?

Yes. Just make sure you do it right—and for the right reasons.

When Deciding Whether You Should Even Cycle At All…

Stick With Keto For At least a Month Before Cycling

Four to six weeks is usually a sufficient period of time. Then, once your muscles have become better adapted to the burning and utilization of actual fatty acids—not just ketones—you’re in a good place to start cycling between Primal and keto, or drift in and out of ketosis as you like.

Premature cycling without a sufficient base of fat adaptation will produce lackluster results across the board. You’ll never quite reach fat-adaptation, so the carb cravings will persist, your aerobic efficiency will suffer, and your fat burning machinery won’t be complete. And if you try to “cycle” without actually being fully ketogenic, you’ll be back at square one. Metabolic limbo is no place to be.

Do It For a Legit Reason

Don’t “cycle” because you’re five days into keto and feel terrible.

Don’t “cycle” because you miss French fries.

Don’t “cycle” because you took the stairs instead of the elevator and totally burned, like, 30 grams of glycogen from each quad.

Cycle because you’ve earned and fine-tuned your fat-burning ability, and now wish to support higher-intensity, higher-volume physical pursuits. Or because you just feel better with a more relaxed approach to macronutrients. Or because you really, really love purple sweet potatoes (I don’t blame you).

Watch Out For the Signs Of Poor Metabolic Flexibility

If every time you eat a carb you get sleepy in an hour and show signs of high blood sugar, even if it’s after an intense training session that should have depleted enough glycogen to make those carbs tolerable, rapid cycling is not for you.

If every time you “cycle” back to keto you feel like a truck hit you and it takes a week to get over the keto flu, rapid cycling is not for you.

When Cycling Back Out Of Keto…

Reduce Fat Intake To Make Room For Any Added Carbs

Fat and carbs together is a fattening combination. Most of the worst processed junk food, the stuff responsible for the obesity epidemic—soybean oil soaked French fries, potato chips, donuts and the like—are bags of fat and carbs. They spike glucose, raise insulin, depress lipolysis, and increase fat deposition while being so nutrient-poor that you’re hungry again in half an hour. But it’s not just the junk food that makes this combo dangerous. If you’re dropping a half stick of butter into your baked potato, even if the butter’s from grass-fed cows who snacked on natto, did CowFit, and fell asleep to a Weston A. Price audiobook recording every night and the potato is an ancient heritage variety unearthed at Machu Picchu, you’re still overdoing it.

I’m not saying to “go low-fat.” I’m suggesting you reduce fat calories as you increase carb calories. What does that look like in practice? A gram of fat has roughly twice the number of calories as a gram of glucose (it’s actually 4 calories per gram of carbs and 9 calories per gram of fat, but close enough). For every two grams of carbs you add, reduce fat by one gram.

Remember That Primal Is Still Compatible With “High-Fat,” Meaning You’ll Probably Still Be Fat-Adapted

Primal has always been primarily about high-fat eating (while being agnostic enough about macronutrients to encompass moderate-carb approaches, too) and the resulting fat-adaptation. Keto isn’t the only path there.

It may take longer. You might never get to the point where you could get someone ketone-drunk by breathing into their mouth. But plain old low-carb Primal will turn you into a fat-burning beast. It’s important to realize that “ketosis” isn’t even the primary goal for most people doing it—the primary goal is building the fat-burning infrastructure that will give you food freedom for years to come.

Consider Time Restricted Feeding/Intermittent Fasting

Restricted eating windows and/or intermittent fasting are great ways to make your transition away from keto onto a higher-carb Primal approach go more smoothly. You’re not leaving ketosis entirely, since for the duration of the fasting period you’ll be consuming your own body fat and generating ketones. You get a nice guaranteed dose of ketosis every day (and night) while enjoying the benefits of relaxed macronutrient ratios—a wider variety of plant foods, in-season fruit, more carbs for athletic pursuits that warrant them.

This could very well be the dietary approach you stick with for the long haul, and that’s okay.

Go For a Hard Workout

Anything done with sufficient volume and intensity will turn your muscles into glycogen sinks—the perfect scenario for someone trying to ease their way back to a more relaxed macronutrient intake. If you have any residual physiological insulin resistance from being keto, a hard training session will re-sensitize you.

When Cycling Back Into Keto…

Remember To Get Extra Salt, Magnesium, and Potassium

Even if you have extensive experience being fat-adapted and your mitochondrial infrastructure is set up to utilize fats and ketones, you’ll still lose a lot of intracellular water, electrolytes, and plasma volume switching back to keto—low insulin has that effect, regardless of prior adaptation. That means eating more sodium, more magnesium, and more potassium. Salt to taste (maybe even a bit more than that), take a good magnesium supplement, and eat potassium-rich foods.

Side note: An unappreciated and keto-friendly source of potassium is zucchini. Seriously, you probably don’t realize it, but a large zucchini has very few digestible carbohydrates and about a gram of potassium. Have at ’em.

Maintain Your Training

Some people suggest taking it easy during the transition. They say to let your body “ease” into the change. Hogwash. Consistent exercise is a great way to upregulate fat burning in muscle tissue. In one study, obese people—a population known for impaired fat oxidation—increased their ability to burn fat by a factor of 2.7 through moderate exercise alone. Imagine the effect it’ll have on you.

The good news is that it gets easier the longer you do this. At this point, 15-ish years into my low-carb, high-fat lifestyle and 3 years into my keto lifestyle, switching between Primal and keto is effortless. It just happens. And if I eat some carbs, I’m no worse for wear.

Of course, you don’t have to cycle between Primal and keto. Stick with one or the other. Or neither. Whatever works, works. Just be honest with yourself.

Thanks for reading, everyone. Take care, leave your tips for the transition down below, and have a great rest of the week.


Berggren JR – Am J Physiol Endocrinol M (2008) Skeletal muscle lipid oxidation and obesity influence of weight loss and exercise

TAGS:  Keto Recipes

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

If you'd like to add an avatar to all of your comments click here!

38 thoughts on “Tips For Cycling Between Primal and Keto”

Leave a Reply

Your email address will not be published. Required fields are marked *

  1. More good advice! A question: everybody and his dog appears to be on a “keto diet” all of a sudden. Is this good? Soon we should be getting all the counter-articles in the various media, warning against this latest fad.

    Any thoughts?

    1. Well, the dog – a carnivore – certainly SHOULD be!!
      I know what you mean. And I am highly skeptical that all those people are truly on ketogenic diets. People are great at self-deception, and many do not understand what it really means anyway. But I am more concerned with my own health than their honesty and accuracy, so I don’t worry about it.

      1. Actually, dogs have been domesticated for approximately 50,000 years now. They have adapted to eating a LOT (not all) of what humans eat. (our cast-offs) They are no longer strict carnivores.

    2. Already happened. Several years ago. Fact is the debate in the scientific arena is largely pro-keto now. It was less conclusive several years back, therefore was marginalized or misrepresented. Much harder to denigrate ketosis now that so much more research has come out.

  2. I am trying to get a little more educated on the process before jumping in, but I am almost there. I need to work on purging the pantry this week.
    My wife is not really on board with going keto yet. I will probably cook most of our dinners, and I am wondering if a higher fat diet would be detrimental for her if she is not following the same dietary guidelines as I am.

    1. Bryan; If you increase the fat intake for both of you, but only you are restricting carbs, then yes, she will see detrimental effects. Like you suggested, I also do all of the cooking in our house. When it comes to adding in the fat, especially sauces and toppings, I just separate the base then fatten mine up (butter, heavy cream etc) and just go primal for her. Seems to work fine. Either way, at least they are whole foods prepared with love!

      1. Thanks. That is what I was thinking. We will probably be mostly primal for the first few weeks at least. I can always get a little more fat for lunch to hit my macros.

  3. If you’re dropping a half stick of butter into your baked potato, even if the butter’s from grass-fed cows who snacked on natto, did CowFit, and fell asleep to a Weston A. Price audiobook recording every night and the potato is an ancient heritage variety unearthed at Machu Picchu, you’re still overdoing it.

    This is a pretty funny line Mark.

    1. Speaking of fat, I’d be interested in Mark’s take regarding the latest attempt to put the kibosh on consumption of coconut oil–specifically, a Harvard professor saying it’s pure poison, probably because it’s so heavily saturated.

      I can’t stand the stuff, personally. I don’t like anything made with coconut, and it doesn’t like me either, possibly because I’m sensitive to the overload of lauric acid. However, this and many other websites tout coconut products as being super healthful.

      So is there any truth to these new claims that coconut oil is actually bad for us? Is there any hard evidence that points to related health issues? Or is this just more of the same-old, same-old that we saw with eggs, red meat, etc.?

      1. Shary, The professor’s statements are incorrect. Google: Dr. Mark Hyman: So is Coconut Oil Healthy? Absolutely! He breaks it down.

      2. Per your statement, he’s saying it’s unhealthy because it’s saturated fat. That’s a different perspective on health. Like, if you were afraid of marbles, you would naturally conclude that everything with marbles is scary. The argument is valid, but not sound.

  4. I know the “and his dog” was meant as a joke, but our dog has bone cancer in her humerus. Rather than the recommended amputation, chemo and radiation treatment path, we have her on several holistic treatments and changed her diet to Keto. No glycogen to feed her cancer cells, and cancer cells (which need lots of energy) don’t do well on ketones. We are just months in, but she is enjoying life everyday.

    1. That is amazing! I’ve read plenty of cancer stories about humans, but that you’re healing your dog from cancer is awesome. So happy for her!

    2. People with dogs can check out for a detailed cancer treatment (and possibly prevention) plan. There is also a good podcast about this that was part of the 2016? (or 2015?) Metabolic Therapeutics conference. There is also a book (that I’ve forgotten the name of ) that is worth tracking down that describes how dogs are very recently evolved from wolves (pure carnivores) and hence may be especially prone to diseases promoted by excessive carb intake.

    3. Even with that because your dog has a tumor you have to be careful of the exact breakdown of too much protein as well as that is a lot of methionine so it is an art you have to know the percentage since your dog has a tumor you might listen to the series of the truth about pet cancer look up the pet cancer Sanctuary that’s in Texas it should give you some information

  5. I’ve been strict keto for 9 ½ months and I love it. Just recently I have begun to feel like I’m missing something. Perhaps I can just up my vegetable intake and that’ll do it but I have realized I do miss having a variety of fruits and vegetables. I’m intrigued with the possibility of cycling between keto and primal.

  6. I think the practical implications of glycogen replenishment while on keto needs a bit more discussion. I am talking here about the finding from Volek’s research, among others , that after 4-6 weeks on keto the body replenishes glycogen stores using fat as the input, but before then the muscles are generally depleted of glycogen (resulting in generally poor high-intensity workouts.) Robb Wolf has alluded to this a lot, and I also find that I need to replenish via moderate carbs or my workouts suffer.

    This adds a layer of complexity to the cycling-in-and-out-of-keto discussion since I haven’t found any good evidence of how that affects replenishment of glycogen stores using stored body fat. Does cycling stop the replenishment? What if one is only able to stay strict keto for three weeks? Would that completely reset the replenishment clock?

    There are lot’s more obvious questions and obviously this will differ from one person to the next. The general lack of focus on physical activity in many (most?) of the keto advocates does not help, but this has what has kept me from going more in the keto direction. My workouts inevitably suffer and I feel lethargic during them if I don’t reload with a moderate amount of carbs 24 hours or so before a hard workout. I would be interested in how others have handled this.

    1. You need sufficient protein even in ketosis if you want to push hard. 1g/lb of lean mass is good. I’ve always functioned well in a sub 20 carb a day lift session, but need enough protein. Check out “Ketogains” if you wanna see how a bunch of examples of how ketosis and exercise can mesh.

    2. I find the opposite, if I workout (weights, 60 yo female) in a fasted state I feel like a machine, my muscles feel awesome when I push them I just feel awesome! So I will have a black coffee with about 7 shakes of rock salt in it around 8am I workout anywhere between 9.30 and 11.00 sometimes I will even have a sauna afterwards. I continue to drink water right throughout the day. My first Keto meal after all that would be at 2.30 to 3 pm. No drama at all

  7. What I have found that works for me most of the time is to:
    1. Skip breakfast most days
    2. BAS for lunch
    3. Perfect dinner pork chops and brussel sprouts.

    No snacking. Lots of low-level movement and strategic exercise with sprints when feeling it.

    Feel great and do not need to worry too much about anything else. Do not worry if I am keto or not, I just know that I feel great!

  8. Great read! My wife and I just passed our 1 year mark on strict Keto. Between us we’ve lost just over 200lbs. I have always been strong in the gym but I find that my 1 rep max on lifts has dropped about 25% (100lbs lost on deadlift, 90lbs lost on squat). I was quite dubious about adding some carbs back to my diet for intense training out of fear of derailing my Ketosis but it hasn’t affected me at all. I’m probably Keto 90% of the time but I’ll jam in some carbs for the occasional CrossFit of heavy lifting session. I’m 44, my wife is 51… we’ve never been healthier or felt better. Metabolic flexibility is the greatest state a person can be in.

  9. Thank you! I’m taking my chronic illness recovery as my full time job, and I think primal-keto cycling might be key.

  10. If every time you eat a carb you get sleepy in an hour and show signs of ##high blood pressure###, even if it’s after an intense training session that should have depleted enough glycogen to make those carbs tolerable, rapid cycling is not for you.

    #### high blood pressure or sugar??

    1. I caught that too…. Mark, please go and correct this While you”re at it, please correct this to “you’ll”…Spend twelve hours one time and never again, and you’re remain a beginner.

  11. Hi Mark:

    I love following a keto eating plan however and have lost a good amount of weight. Unfortunately, I have no gall bladder and my body has not adjusted to keto as I have had several “accidents” even while taking Ox-Bile. Any idea how I can move forward without the current stomach distress I am experiencing?

    Thank you.

  12. Hi, That has to be one of the best articles I have read. Funny too! Thank You for the great advice. I have been strictly keto for a year and a half. It is effortless now. I have tried a few new products with cassava in it without a problem. Grain free nacho chips and Simple Mills bread mix. yum! This has made my keto options a little more fun at times. Thanks Again
    Janet ?? Thousand Oaks, California

  13. Thank you for your books and blog, they have been very useful in my quest to gain muscle and lose stubborn fat, I am disciplined in my weight training and really don’t crave sweets, however even though I’m slowly gaining muscle, I am not losing fat. But your information, helps me feel like I’m getting closer to finding the answer that works for me.

  14. Great article. You mentioned “signs of high blood pressure.” What would those signs look like? I’ve noticed a few times when I indulge and eat higher carb and higher sodium foods such as chips, I find I have a rapid and irregular heartbeat the next morning. Could the sudden surge of carbs and sodium be doing it?

    1. It was supposed to be high blood sugar but he mistakenly wrote blood pressure. A few of us pointed it out but he has not corrected it.

  15. On Primal for 8 years and keto for 3 months and during that three months of keto had to do some carb tweaking to enable me to play hockey 3 times a week.

    I merely carbed up a couple of hours before a game with a banana or baked potato which would probably normally knocked me out of keto and put me into the 70 g of carb range for the day.

    But since I played relatively close to the carb loading I actually seemed to stay in keto. I check my blood every day at around 4 PM and although the numbers are in the .5-.6 range the next day, I’m still in keto. Normally I’m in the 1.1-1.5 range.

    So the added carbs on game day don’t seem to be an issue.

  16. I chose to return to a primal nutrition plan after a year on keto to heal my thyroid and bring my hormones back into harmony. Primal seems to be the best option for me at this stage in my life (mid 40s). I even lost the 15 pounds I’d gained in the course of a year in about 6 weeks of primal. I look and feel SO much better now!

  17. Mark said,”Fat and carbs together is a fattening combination.” I believe this is only true if we are talking starchy carbs not Broccoli dipped in real butter.

  18. Another great read! I’m considering mimicking our natural environment, and dipping into ketosis for the winter months, then coming out of it in the summer. Following the natural availability of fruit, veggies, and honey.

  19. Love this! I’ve been doing it for months and it’s the most realistic approach I can expect for myself. I don’t see the ultra quick results like I would fully Keto adapted but that’s not why i’m doing it. If you can’t find what you are comfortable committing to, you are setting yourself up for failure.

  20. I was so excited to see this blog title!
    After 9 years of Primal, I went strict Keto for 6 months, achieved my goals (lost 46 pounds total – including a few I’d regained – & reduced my diabetic fasting glucose to consistently under 100 – and as low as 65! when fasting). For the last 8 months I’ve been cycling between 4-ish weeks Keto to 5-7 days Primal.
    I IF 18/6 daily, plus 36 hours weekly (broken with one FMD meal). Also recently finished a long (5-day) fast using the Fasting Mimicking Diet but with keto macros, homemade.
    I worried that I’d lose my gains with cycling, and indeed my numbers *do* rise during my Primal phases, but then shrink right back *+ lower each time* after I return to Keto. So I’m on the verge of new territory weight-wise.
    I continue my regular workouts during all cycles.
    It’s perfect for me because I begin to feel depleted after a month or so on Keto, and relish my purple sweet potatoes and less restriction during my Primal cycle. But at the end of it I feel stuffed and yearn for the lean, clean feel of Keto again.
    This is a pattern I can happily live the rest of my life on.
    Note – I track carbs during all cycles, because it’s easy to get carried away. <20 net (all fiber from veggies) for Keto cycles, <60-ish net for Primal. Also I only eat Keto sweet treats during Primal carb-ups (none during Keto periods).
    Thanks for the great info, I can always depend on you to report on just what I want to know!

  21. Thanks, Mark, for sharing this helpful tips for keto cycling. We should understand that consistency is the key in everything we do. This post also clears that you should only stick with one that is primal or keto or none of them. If you are honest with yourself then it works.