Meet Mark

Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...

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July 25 2018

Exercising While Keto: 11 Tips for the Transition (and Long-Term)

By Mark Sisson

People go keto for many different reasons. Some want to get better at burning fat so they have a clean, reliable source of steady energy at all times. Some people are treating a neurodegenerative disease, or trying to prevent one from occurring in the first place. Others just want to lose body fat, take advantage of the cognitive effects of ketosis, or stop seizures. Those are all common reasons to go keto. Another reason people go keto is for the benefits to physical performance.

Keto increases energy efficiency. You can do more in the aerobic (fat-burning) zone than a sugar-burner.

Keto spares glycogen. The more fat you’re able to utilize, the more glycogen you preserve for truly intense efforts.

Keto builds new mitochondria. Mitochondria are the power plants of our cells. More mitochondria means a larger engine.

That said, the performance benefits take a few weeks to manifest. During this time, a common side effect of the keto transition is reduced performance in the gym. People report feeling sluggish, slow, weak, and flabby in the days and weeks leading up to their adaptation. It’s understandable (and somewhat expected) why this can happen:

Fat provides tons of energy at a slow rate—but you’re not great at accessing it yet.

Glucose is more scarce but provides energy rapidly—and you just took it out of your diet.

Is there anything you can do to improve your performance in the gym during the transition?

Preserving Performance During the Keto Transition

Increase Fat Content

This goes without saying. Of course you’ll be eating more fat on a ketogenic diet. Right? What I mean is you should increase fat even more than you think for the first week. This has the effect of increasing AMPK activity, which hastens the creation of fat-burning mitochondria, upregulates fat metabolism, and speeds up your ability to utilize ketone bodies.

Increase Intake of Specific Fats

Certain fatty acids seem to increase AMPK more than others. The most potent ones I’ve found are:

Include some mac nuts, EVOO, and wild fatty fish (or quality fish oil) on a regular basis.

Take Your Electrolytes

Electrolytes are already essential when transitioning toward a ketogenic diet. Since they regulate muscle contractions, heart function, intracellular fluid balance, and nerve impulses, they’re even more important when you’re exercising,  Try increasing mineral intake by 4.5 grams sodium (about 2 teaspoons of fine salt or a little under 3 teaspoons of kosher salt), 300-400 mg magnesium, and 1-2 grams of potassium each day on top of your normal food. Going keto really flushes out water weight, and tons of electrolytes leave with it.

Stick To Weights and Walking

The big problem with physical performance during the keto transition is that you’re not great at burning fat, you’re still reliant on glucose to fuel your training, and you don’t have much glucose coming in. For the transition window, this makes high intensity, high volume training a bad idea.

Running a race-pace 10k is going to be hard. Participating in the CrossFit Games is a bad idea. You haven’t yet built the machinery necessary to make those work, nor do you have the glucose necessary to tide you over. You know what will work? Weights and walking.

Walking is totally aerobic, using almost no glycogen of note. Weight training can be glycogen-dependent, but doesn’t have to be if you keep weights high and volume low. Think low (2-6 reps) volume weight training. Whatever you do, the key is to make sure your training is low-stress.

Stick to weights and walking and you’ll hasten keto-adaptation, not harm it. Then you can resume some of your normal activities.

Take Creatine

Creatine boosts muscle content of phosphocreatine, which we can use to generate large amounts of ATP in a short period of time for quick bursts of speed or strength. This doesn’t dip into glycogen or fat. It’s ATP-PC, or ATP-phosphocreatine. If you’re going to sprint or lift heavy stuff, you’ll definitely want extra creatine in your muscles.

No need to “pre-load” creatine. Just take 5 grams a day and be sure to drink plenty of water and get plenty of electrolytes (which you’ll already be doing on keto).

Sprint Carefully

If you’re going to sprint on keto, keep a few tips in mind.

Short sprints—3-5 seconds.

Plenty of rest—as much as you need to go as hard and fast as the last one. This gives you the chance to replenish some of your phosphocreatine.

This won’t fully replenish your ATP-PC stores. You won’t be able to go as hard, or do as many reps as you’d like in subsequent sprints. But if you absolutely must sprint, this the way to do it without relying on glucose. Look for the sensation of diminished power. That’s when you’re hitting the PC wall and will start dipping into glucose. Avoid that sensation. Stop short of it.

Don’t freak out if you “dip into glucose,” though. Yeah, dipping into glucose constantly will inhibit keto-adaptation in the early stages, but once or twice won’t make a big difference. Just don’t make glucose-intensive work a habit.

Get Primal Endurance

Brad Kearns and I wrote Primal Endurance because endurance athletes needed a better, safer, healthier way to do the thing they love-hated. I know, because that was us. We both got out of serious endurance athletics because it was harming more than helping us. But that doesn’t mean we stopped missing it. Once an endurance athlete, always an endurance athlete. You can’t shake the bug.

Primal Endurance shows you how to build a powerful, long-lasting aerobic base using primarily stored body fat. It’s the perfect complement to a keto lifestyle, especially if you want to optimize your athletic performance and make your physical activity support rather than inhibit keto-adaptation.

Understand the Purpose of Training

Lifting in the gym isn’t a competition. You’re not being paid. The whole point of lifting weights, running sprints, and doing low level aerobic activity is to get better at doing those things. It’s not about “winning” every workout. That’s what training is—accepting paltry results with the assurance that you’re getting better. Think about it.

When you add 50 pounds to the bar, it’s harder. The bar moves more slowly. You can’t do as many reps. From your brain’s perspective, you’re suddenly “weaker.” Yet, it’s the best way to get stronger in the long run.

When you try a new sport or physical activity, you’re no good. You’re a beginner. People you’re sure you could trounce in your preferred activities are destroying you. This doesn’t mean you should give up. It means you have to get better. And if you stick with it, you will get better.

When you train on your newly keto diet, think of it like you’re increasing weight, upping the intensity, or learning a new sport. You’re not weaker. You’re not getting worse. The training is getting harder. The pain is increasing. And, although it might not feel like it right now, you’re going to be better off in the long run.

Once you’re fully fat-adapted and able to utilize fats, ketones, and glycogen, you’re going to be an unstoppable force.

Okay, that’s short term. What about long term?

How To Enhance Performance Long-Term With Keto

Carb Cycle When Necessary

Once you’ve been keto for at least a month, don’t be afraid to cycle in carbs to support your intense training. If you’ve depleted muscle glycogen with an intense training session, you’ve created a glycogen debt and any carbs you eat in the hours following that workout will go to repleting that glycogen. Best of all, intense training upregulates insulin-independent glycogen uptake immediately post-workout. That means if you do it right, you don’t even need to increase insulin to shove those glucose molecules into your muscles.

Carb Cycle the Right Way

Many people do carb cycling on keto completely wrong. They spend two days binging on bear claws and gummy bears then wonder why they’ve gained weight and lost progress. A few tips:

You probably need fewer carbs than you think. A little snack of 20-40 grams of carbs right after a really intense workout can make all the difference in the world without knocking you out of ketosis, provided you’ve accumulated enough of a glycogen debt.

Choose the right carbs. A sweet potato the night before to top off glycogen stores, a cooked-and-cooled white potato (diced and quickly seared until crispy in a pan is my favorite way to eat these), or UCAN Superstarch (whose slow absorption has minimal impact on insulin and thus ketones) are all good choices.

Do it for the right reasons. Don’t carb cycle because you miss French fries. Carb cycle because you’ve depleted glycogen.

And hell, briefly exiting ketosis isn’t the end of the world. Most people doing keto aren’t doing it as a life or death intervention. They just want to look, feel, and perform better. Don’t let keto become an ideology. It is a tool for your pleasure.

Chase Results, Not Ketones

In my experience, the people who focus on results rather than ketone readings do best.

Heck, if you spend half your time stressing about your ketone levels, the resultant cortisol will probably trigger gluconeogenesis and inhibit keto-adaptation by introducing a flood of new glucose into your body.

Are you leaning out? Thinking more clearly? Skipping the afternoon nap and breakroom donuts without even thinking about it? Lifting more? Running easier? Lab tests improving?

Then you’re good. That’s what matters.

Besides, the point of keto-adaptation is fat-adaptation—the ability of your muscles to utilize free fatty acids. That’s the real power of going keto, because once the fat-burning machinery is established and your muscles can use fats directly, you have more leeway to eat protein and cycle carbs.

Those are the tips I’ve found to be most useful for people acclimating to exercise on a keto diet. What’s worked for you?

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23 thoughts on “Exercising While Keto: 11 Tips for the Transition (and Long-Term)”

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  1. Is there any significant difference between your book and the similar book put out by Phinney and Volek a long time ago. It seems that they continue to be the leaders in this area of research.

  2. Huge yes to tracking results, not ketones! And pretty much everything else in this post. I have been keto for several years now but have no idea if I am ever truly in ketosis. I just know I have more energy, better focus and better body composition (with less exercise, I should add) I totally go by how I feel. Definitely adding more fat in the beginning is helpful, and it has the benefit of keeping you very satiated. It’s gotten to the point that this lifestyle is super easy to maintain, even when traveling.

  3. I don’t believe in supplements, per se… but I love me some creatine!

    I had a methylation issue (mthfr and comt related) that I resolved with the addition of Liver, Bone Marrow and a little creatine and choline (egg yolks). Did you know that a good 40% – 50% of methylation resources are used to synthesize creatine…. If we give our bodies the creatine that it needs, methylation improves. Makes sense, doesn’t it!

    Get Primal Endurance… one of my favorite books and perfect for the keto transition. Double thumbs up.

  4. What kind of potassium supplement – citrate, chloride, etc.? Also they tend to come in 99mg dosage, so getting 1-2 grams would mean popping 10-20 pills. Am I missing something? Thanks for the post.

    1. I would be cautious about supplementing potassium. Deficiency isn’t all that common, and too much can make you pretty sick. You get a decent amount in food. For an easy extra 700mg, have an avocado. Salmon, spinach, and chard are also good sources. Unless you are noticing specific symptoms of deficiency, I wouldn’t worry too much about it. Worry more about magnesium, in which practically everybody is deficient. Mg deficiency commonly causes muscle cramping. I take a magnesium asporotate supplement that also contains some potassium and bromelain (which helps with bioavailability of the minerals), and that works for me. Of course, everyone is different. The main thing is to listen to your body. I took a little too much potassium once and it came right back up rather violently — not gonna make that mistake again! 🙂

    2. Hi Julie, I can relate to your question because I had the same one a couple weeks ago. I was in keto for about 2 months, and still had issues with muscle cramps – each time I exercised, and I was even waking up due to muscle cramps in the middle of the night. I was well hydrated, drinking electrolytes and about 120 oz water per day (I weigh 160lb), so I figured dehydration was ruled out. I then got a Magnesium/Calcium/Zinc supplement and Vitamin C and took those for a week. Still muscle cramps, so I didn’t think my problem was Mg-related. Then I got a Potassium supplement (99mg, Nature’s Bounty brand) and my muscle cramps have subsided, thankfully. I was surprised, since 99mg is only 3% of daily value, but very happy that it worked out. Hope this helps.

  5. I have fund that I need to eat a smaller dinner if I want to get results but then it is particularly hard to workout in the morning while hungry. I have read that the best way to burn that fat is to exercise fasted. Any thoughts on what to do here?

  6. I love your tips. (Even though I’m an older women who’s not not doing intense exercise 🙂
    But I must fat adapt and get into keto for diabetes
    But, I’m having an ‘odd’ issue that no one seems to have heard of.
    As soon my blood sugar starts to drop, my peripheral neuropathy pain flares uncontrollably…. So all my attempts have failed as that pain is too much.

    This is making me crazy, as, of course, I’m doing all this to reverse the diabetes.!!!

    Any ideas or hints would be so greatly appreciated.


    1. Jeanne, I’m getting the feeling that you might be pushing things a little too hard. A lot of people have success controlling their diabetes with just the Paleo diet. I wouldn’t think a keto diet would be absolutely necessary. If keto eating causes you pain or other problems, then don’t do it. Simple, yes?

      Also, start out very slowly and give your body time to adjust. Gradually transition into fewer carbs over a period of 6 months or so and see how you do. It doesn’t need to be a case of all or nothing.

      Start out by eliminating the sweets. Then either get rid of or drastically reduce consumption of most grain products. Those are the two biggies. If you can manage to do that much, it should help considerably.

      Regarding exercise, you don’t need to go overboard with it. Try just walking. Start with 15 minutes once or twice a day and gradually increase it as you are able to. In other words, do what you can and don’t worry that it might not be enough.

    2. I used keto to reverse my diabetes. When my blood sugar first started dropping, I got pin and needle sensations in my feet. I was freaked out at first, but a little research suggested that healing nerves give off those sensations as they repair themselves. I didn’t even know I had neuropathy in my feet until that point; it was fairly mild numbness that had crept up on me so gradually I never noticed. It took a week or two for those pins and needles to go away, but it did heal. Maybe the same thing is happening to you, but with more significant damage to heal.

      Good luck,

  7. Think of peripheral neuropathy as starving nerves. With blood sugar issues and circulation issues in the extremities, nerves get unhealthy and tell you through pain. Go keto, move more, move more of you to improve health of feet and hands. Move all the joints in the hands and the feet and all their muscles. Go slow.

  8. Nicely written post. Thanks to sharing valuable information about how one can easily enhance their performance long term by following Keto. The post also describes how one can preserve their performance during keto transition.

  9. Should I be worried that since starting Keto 2 months ago that I haven’t experienced a decline in performance at all? As soon as I started eating Keto I found my performance in the gym actually increased from the very beginning. I never experienced the weakness, fatigue, etc. I use several Perfect Keto products like their pre workout, MCT oil Powder, and exogenous ketone base. Maybe that helped because I’ve experienced nothing but great benefits. So I am wondering if this is normal, or should I expect to feel that decline in performance as I progress further?

    1. Don’t knock success. If your performance starts to slide, or if you start feeling unwell, THEN you can worry. Meanwhile, just enjoy the fact that things are working for you.

  10. I am confused by the repeated recommendation here on MDA for carbohydrates with workouts. Before I had ever heard of ketosis I was careful to avoid them for hours around any intense exercise or heavy work as I’d read the shut down the production of human growth hormones, at least in those of us over a certain age. My routine was after tabata or any heavy work then a motivational treat of sardines or octopus in olive oil and no carbs the rest of the day until dinner to prolong the benefits as long as possible. When I went “zero carb” I figured that became redundant or rather was automatically built in. Anytime I exert enough to stimulate HGH I just figure it will last as long as possible with no special eating schedule. Not sure why your go out of your way to eat your only carbs just when they’d shut down the production of the increasingly hard to get growth hormone. Is the idea that this sub insulin level of “refeeding” doesn’t shut down the muscle boosting hormone or is that just not a priority? Or is this not a universally accepted phenomenon? I know that many athletes who are focused performance and recovery follow the exact opposite approach to this, binging on carbs to reduce recovery but they are generally young so can make HGH easily and not in it for their health just to win. This was recommended for long term health not sports performance.

  11. I think it’s important for women to keep in mind that keto can be a powerful appetite suppressant. I found that it was way too easy not to eat on keto; I was eating according to WHEN (when hunger ensues naturally), but I was rarely ever hungry. This led to extended fasts, which coincided with a surge in estrogen, zero testosterone and hypothyroidism. Of course I can’t say with certainty that keto caused my hormonal imbalances, but after following my naturopath’s advice to eat three meals a day with at least two servings of starchy carbs (for example, sweet potato, cooked and cooled white potatoes, plantains) I am feeling like unstoppable again, like when I first went primal 3 or 4 years ago. As Mark says, pay attention to your body! If you are gaining weight or experiencing hormonal imbalances while on keto, perhaps it’s time to reevaluate.

  12. I found it rather easy to work out while in ketosis by fasting for 48-72 hours so that I got in ketosis right away. Then I made sure to eat a keto diet and had absolutely no trouble with weakness during or after working out. Neither my husband nor I had much of a struggle when working out, even during multi-day fasts…as long as we were diligent about drinking a “saltwater” electrolyte solution on fasting days.

  13. Hi Mark,
    If I am an athlete that wants to improve performance, but my goal is also to lean out, should I utilize a carb snack to improve performance or just rely on my fat stores for energy? I am a Powerlifter and fairly lean (24% bf). I want to still be able to do heavy sets of 3-5 but have been struggling. I am about 4 weeks into keto. Thanks!

  14. Hey Mark,

    I’m an endurance cyclist and mostly agree with you but have a few thoughts to add.

    The first is that full aerobic adaptation for keto takes a long time. There aren’t great studies on this, but all the anecdotal data I’ve seen – and my own experiences – say that 4 weeks is the minimum to start feeling decent again, and that getting really adapted can take months. I mention this because it’s important to have reasonable expectations as an athlete.

    I also want to take a little issue in using the term “fat burning zone”. Aerobic athletes on low-carb diets burn lots of fat even at high intensities, though of course this doesn’t really apply at anaerobic intensities.

  15. I am on my second week of eating keto and am at the beginning stages of marathon training. I am curious if once my body is fat adapted, and say I knock myself out of ketosis one day, will that affect performance once I go back to keto. Will my body be effective at burning fat from then on if I go back and forth or even hover in the low carb range?