Long-Distance Running on a Low-Carb, High-Fat Diet

Long-Distance Running on a Low-Carb, High-Fat Diet

Humans are natural endurance athletes. While the concept of “carb loading,” or the use of sports drinks and gels in endurance events are increasingly popular, human physiology is perfectly set up to use fat as a fuel for endurance exercise.

Olaf Sorensen, seen here in the blue shirt, is a 40-year-old long-distance runner who will be running a marathon soon. What’s unique about his upcoming endeavor is that, first, his goal for this event is to beat his grandfather’s Olympic qualifying time of 2 hours and 40 minutes. But what is particularly unique about Olaf’s plan is that he plans to accomplish this feat on a high-fat, extremely low-carb diet. He will essentially demonstrate to the world that being in a state of ketosis (burning fat as opposed to carbohydrates) is an extremely efficient human adaptation permitting long stretches of efficient physical activity.

Olaf does a lot of his running either barefoot or with minimal footwear, again emulating our forebears. I really appreciated his instructions when we ran together. But while I’m definitely dialed in on the keto adaptation part of the story, I’ll likely stick with my running shoes.

We will be following Olaf’s progress and will soon provide information about the movie being made about this incredible athlete.

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  • Lynn Dell

    Definitely keep us posted!

  • Al

    I don’t think our forebears ran barefooted on asphalt. :)

    • David Perlmutter

      No argument there!

    • Jim

      I have been running in minimal shoes since 2009 (Usually Walmart or Kmart beach shoes to be exact). The first thing that I do after I purchase them is remove the insole. I believe that running with minimal shoes or barefoot helps protect my knees. Also, $9.00 for a pair is a fair price. :)

  • Craig

    It also appear by your strides that you are running Pose or Chi. Am I correct? I ran marathons with minimal footwear running Pose. Best of luck with your training.

    • olaf

      Craig, I’m more or less self taught in forefoot running, recently as I was working with the UF Human Performance Lab, their trainer Scott Greenberg helped me to clean up my technique, but that’s the first formal instruction I’ve had, it helped a lot by the way. I’m not really familiar with Chi or Pose to be honest. Thanks for your support.

  • Jason

    In November I ran a marathon keeping my heart rate under 145 bpm (aerobic training). Before the race I had a cup of coffee with butter and coconut oil, no carbs. During the run I did not eat or drink anything. It took 4:50, about an hour and a half slower than my typical marathon, but at the end I was not fatigued and had no soreness the next day. Low carb/high fat is excellent for endurance activities.

    • Peggy Holloway

      My 71-year-old partner and I, age 60, are distance cyclists. We do multi-day rides with only coffee before we ride each day with an average of 70 miles per day and never eat at the SAG stops. We did a century in September on a very hot, windy day with a hilly course. Again, we did not eat until after we finished the ride and we were amazed that we still had energy to spare. We have just started the “bullet-proof” coffee regimen and I’m curious to see how this effects our cycling next season.

      • Cathy Valenti

        Peggy, what’s the “bullet-proof” coffee regimen? I hope it’s drinking coffee for breakfast in the morning, I already do that!

        • Peggy Holloway

          “Bullet-proof” was coined by Dave Asprey, the Bullet-Proof executive. His basic idea is to blend quality coffee (he’s particular about it and I’m not so technically I may not be bullet-proof) with coconut or MCT oil and butter or ghee. The idea is that this gives a person mental clarity and physical energy to start the day and replaces “breakfast.” Works for me.

          • Cathy Valenti

            I wonder if it would work as well to have that separately somehow. I’m not sure how I would like the taste, as I drink my coffee black. I’ll look him up for more information. Thanks!

          • Wade Irwin

            Cathy,
            I drink a cup of black coffee daily with one teaspoon of coconut oil. I really can’t taste anything but the coffee. I then go to the gym and work out. I have never run out of energy and I feel like I’m able to do anything . This is a major change from when I was into the high carb/low fat diet recommended by the medical professionals. I am a 67 year old male and can hang with people half my age or younger as far as workouts. I am absolutely amazed at how I feel now!

          • Cathy Valenti

            I’ll try it tomorrow. I just love my coffee black. So now I wonder, with my longer trail runs looming – does anyone have a good recipe for low carb, gluten free, energy bars that adhere to the Grain Brain diet?

          • Alan Chidley

            I just saw a recipe for gluten free coconut Plover bars. We look for it and send in next text. Alan Chidley.

          • Alan Chidley

            Hi Cathy. I found the power bar recipe. Go to wellnessmama.com
            She has 7 great recipes for people who want to add more coconut oil to their diet and the power bar was one of them. I hope this helps. My wife had 6 autoimmune diseases and give problems with yeast/thrush. I am so excited about what the increased coconut oil is doing. The benefit for me has been the increased energy for my triathlon training and raising my HDL. My LDL has always been very very low but HDL had been Problem for 40 years. Next blood test on four weeks should reroll the story.

      • Paige Kelly

        Do you find you eat more than what the book outlines in it’s sample meals being a long distance cyclist?

        • Peggy Holloway

          We really don’t eat that much. Last Saturday, we did a fairly hilly 62 mile ride starting at 7:00 am. Beforehand, we had our mugs of bullet-proof coffee. We don’t “snack” on our rides, just drink water. After finishing, we went home and did some normal daily activities but still didn’t feel like eating. We had a small dinner around 6:00 pm of some left-over meat loaf and asparagus and a salad. Of course, what we do eat is very nutrient-dense, but actually volume of food is fairly small.

  • runn

    4:40? or 2:40…

    • David Perlmutter

      Good catch! Thanks for keeping me honest.

  • Danna Seevers

    Who’s that guy out in front!!? He’s just as fit as the 40 yr old!! :>)

    • David Perlmutter

      Don’t I wish!!

  • Gontrand

    I love the story and hope to see the movie soon. I’m certifying in metabolic efficiency training for athletes and am a Triathon Coach as well (USAT Certified). I can provide many examples of how efficient training and competing in a state of ketosis is and even point out the greatest one: Iñaki de la Parra, 2012 UK Ultraman Champion.
    For those not familiar with an Ultraman, it is a triathlon made in succesive days equal to double the distance of an Ironman (2 x 4k swimm, 180k cycling and 42k run).
    Dr. Perlmutter, I cannot express but great appreciation for having read your book “Grain Brain”. It was an enlightining experience!

    • Alan Chidley

      Gontrand, I am a senior triathlete coming off a very long illness and would like to talk about using you as a coach. Thanks, Alan 916-276-0433 plz call or txt

  • Cathy Valenti

    I’ll be following your progress, Olaf! I would run barefoot if I could, but instead I wear minimalist shoes on our rocky trails. Also training for a 50K (Bryce Canyon this summer) and am a week in on the “Grain Brain” plan. I’ve always been very slow, walking up hills, and running down. Definitely not a competitive runner but I have fun. I believe cutting back on the carbs will improve my running and my overall health.

    • olaf

      Cathy, I mainly run barefoot when on the beach or on grass. I’ll run in Luna sandals or Vivo Barefoot shoes normally. When introducing someone new to forefoot running, we always start barefoot to get a feel for the technique. Keep going with the Grain Brain diet and you will see amazing results in your running as I have. These days, I run first thing in the morning before breakfast and it’s not unusual for me to run 3 hours and still not be overly hungry, this diet works.

      • Cathy Valenti

        Thanks, Olaf. When there’s no snow on the ground I’ve run in Soft Star shoes. I went with them because every other shoe inflamed nerves in my toes. With cold weather and extra rocky terrain I wear Altra shoes without the insert. Looking forward to seeing how the Grain Brain diet makes me feel overall, so I’m keeping a journal. It does keep hunger away (especially carb-induced). I’ll let you all know how I do.

        • olaf

          Hey Cathy, when I went really serious on the ketogenic diet, I ate pure smoked organic pork fat for my dinner, as you see in the photo below.
          This would be a side dish to whatever protein and other vegetables I was having. It worked for me very well, especially as my runs were always the very first thing in the morning. Keep me posted and let me know if I can help.

          • Peggy Holloway

            OMG – we do something that looks a lot like this! We purchase pork belly and roast up a big chunk, then mix it with kale, broccoli, brussels sprouts, or whatever. We add a bit of it to almost everything we cook in our crockpot, which is our “go-to” method for cooking up meat and veggies.

          • Peggy Holloway

            The craziest thing that happened last summer was when we started adding pork belly to many of our meals along with our “bullet-proof” coffee. Although we both were happy with our weights before making those little changes, we were both actually shocked to realize that we were losing a few pounds and body fat. Seriously, we were eating more and more fat and feeling more and more satiated, and losing weight and fat without trying! It seemed so absurd when we were constantly hearing about acquaintances struggling to eat less and exercise more and barely seeing their scales budge!

          • olaf

            Peggy, It sounds like our dishes are very similar, I also add mushrooms, ginger, garlic and lots silver beet as you can see below. Topped off with as much heavy cream as possible.

          • Cathy Valenti

            That’s the kind of meal I could eat. I’m training for an ultra-marathon – I need to lose at least ten pounds or more for this, and so far, this plan has been awesome. If you are interested, here is the story of my running history. My next ultra will be run while following the ketogenic diet. http://idahocat.blogspot.com/2014/01/yes-i-am-runner.html

  • Daniel Ros

    Any one-size-fits-all diet is about as smart as hair care that works for everyone. That would be the same as walking into a clothing store and having all the same dress for sale in every store in the mall. What ever side of the isle it is, whether is the carb side or the fat/protein side its completely ignoramus, short sighted, and completely misses the VERY FOUNDATION OF ALL BIOLOGICAL SCIENCES. Humans adapt to environments JUST LIKE ANY BIOLOGICAL ORGANISM!!!! Different climates, food sources, environments and different people adapting to those environments is nothing short of the FOUNDATION of nutrition just like the FOUNDATION of math is basic adding and subtracting.

  • Nee

    Would appreciate some examples of how you fuel. Can’t stand gels and blocks of syrup, but would like to know what you would suggest for marathon training/competiton. I haven’t to that point yet in the book. Thanks!

    • Nee

      ..haven’t *gotten* to that point yet…

  • Mary

    How should you fuel for running? I was on a low carb diet only one to none daily (completely gluten free). Once I started running I felt my body craving carbs and became so confused, gained weight even when logging more miles. How can I fuel up before, stay strong during, and recover with? I know that sugary drinks and gels are not the way to go.

    • Gontrand

      My recommendation: GENERATION UCAN, go to the web page, you’ll be surprised.

      • Mary

        I actually have the UCAN Product but have been hesitant to use it because it is made out of corn. Does anyone else have an opinion on the UCAN product?

    • Peggy Holloway

      You were not ketone-adapted yet. It takes about 2 weeks and you need to be sure to keep fat intake at above 60%. 85% is even better.

  • Joe

    Very interested! Look forward to hearing how it goes, and hopefully share some helpful hints in refuelling. I’m an avid runner, and am transitioning to a ketogenic diet myself

    • olaf

      Joe, the only thing I can say on the subject of refueling so far in my experience is that when you are properly keto adapted, it seems like you don’t need to re-fuel. I always train on an empty stomach and have done up to 3-4 hrs of running without any hassle. So my suggestion would be to focus on getting into ketosis and your fueling will take care of itself.

      • Sandy

        Do you train at a low HR to achieve the desirable fat burning ratio?

        • olaf

          Sandy, yes – I use the Maffetone Method, 180 minus your age and I’ve added 5 because I’ve trained for a long time according to the formula. I train around 145.

      • Peggy Holloway

        As I stated above, my partner and I go 6 to 8 hours cycling without refueling.

        • olaf

          Peggy, I find that awesome, I use the bullet proof coffee myself.

  • Alison

    What about anaerobic activity? Yes, aerobic training/racing is easy enough on the body to give it time to break down fat to use as a fuel source. But, high intensity interval training/racing needs to have fuel readily available, easy to break down, and easy to digest and use. This is where, in normal circumstances, simple carbohydrates have come into play. How does one use fat as a fuel source for high intensity training and racing?

    • olaf

      Alison, I was tested recently at University of Florida Human Performance Lab and my fat burning only started diminishing when my HR hit 155-160 and the doctors there believed it was possible with proper training and diet to keep pushing that limit further and further.

      • Alison

        Thank you and good luck!

        • Andrew McKechnie

          I also have the same question as Alison and I’d like to know some more. I’m a 38 year old club cyclist. The cycle racing I train for involves covering long distances (80-120km including hills) at an uncomfortably high aerobic rate (for me 150-165 bpm; in comparison a comfortable all day 200km+ aerobic rate for me is below 150bpm). Towards the middle of the race attacks come from a few riders over the anaerobic threshold rate that last for up to a minute (for me over 175 bmp). Then if you’re able to get away in a group, you’ll try and keep at an anaerobic threshold pace to keep away until the finish line, say 30 minutes (for me around 170 +/- 5bpm) and then finish with a sprint finish (max HR 180bpm).

          Endurance wise, I can certainly see the benefits of a being in a ketogenic state producing an ultra efficient slow burn, steady metabolism. But how will the attacks and subsequent break away effort be sustained in the absence of oxygen with this type of fuel compared with glucose? In a ketogenic state can fat be rapidly metabolised to fuel muscles in the absence of oxygen?

          • Alison

            Perfectly asked, Andrew, as I am also a cyclist.

    • Larry

      I am a personal trainer/sports nutritionist and low carb advocate. I am not in a ketogenic state, but keep carbs low and routinely lift heavy on no carbs and teach/do an advanced level fitness bootcamp in a fasted state. I have no problems lifting heavy or doing high intensity circuit work w/o carbs; in fact I’ll perform better.

  • Brody Hankinson

    Very interesting testimony regarding a successful marathon runner using a high fat-low carb program. Also, I can attest to running with “zero heel” footwear. As a former athlete, I can tell you there are many advantages of barefoot or “zero heel” shoes (quicker acceleration due to simple physics/range of motion, less ankle sprains because there is no “ledge” for you ankle to roll over), but most importantly, as we get older it’s better for our joints and low back. Barefoot or zero heel shoes force us to use our foot more as a shock absorber, the way the big Chief upstairs built us to use it. With that said, if you’re switching from running shoes (with a big padded heel) to barefoot or zero heel, it’ll take 6 to 18 months to fully adapt because the ankle and calf muscles have to strengthen (which will also improve joint integrity). I’m 38 and I play basketball, football, and run in zero heel shoes. I’ve picked up a step in my game, my back doesn’t hurt like it used to, and I haven’t had a major ankle sprain in years…HIGHLY recommend zero heel products. By the way, my aunt works with you Dr. Perlmutter…she sent me your book for Christmas….I enjoyed it and am going to use some of the recipes….thanks so much! -B

  • Michelle

    Interested to hear more about this. My husband is a triathlete and just started this diet since the new year. I have been eating grain free, low carb, high fat for a few months for RA. Much easier with him on board. In your book you talk about low carb, gluten free crackers. I have found ” Flackers”. Do you know of any others out there that are acceptable? Thank you

    • MJ

      Mary’s Gone Crackers, gluten free and low fat. Tasty!

  • ri

    ok Dr Oz is claiming that his 2 week quick start diet to shed lbs fast means you must eliminate certain things-I agree with wheat, sugar and alcohol but he even says coffee because we add cream and sugar and also dairy because its inflammatory-what the heck? this is so confusing I thought dairy is acceptable fat and all as long as were staying low carb and I will never give up my coffee. Glad hes finally on board with the no wheat because he used to always recommend whole wheat this and whole wheat that but I think he read Grain Brain so that’s good-but can someone tell me why dairy has to go. Dr Perlmutter said its acceptable did he not? I love cheese and I love coffee with cream!!!

    • David Perlmutter

      Aside from casein allergy, I don’t see an argument against using small amounts of low lactose organic dairy products

      • ri

        right low lactose but doesnt low fat dairy usually have higher amounts of lactose since they take the fat out they have to replace it with something -ill never go back to skim milk

        • Peggy Holloway

          Why would anyone use low-fat dairy? We do very well with heavy cream in our coffee, but when we have encountered unwitting baristas who don’t get it and substitute half-and-half, the results aren’t pretty! Full-fat dairy is the only way to go.

          • ri

            thanks Peggy I believe so as well because when they remove the fat they add more carbs I heard so higher fat is better for you and tastes better I just got confused because dr oz said dairy is inflammatory but when I read grain brain dr perlmutter said we can enjoy moderate amounts of dairy from cream and cheeses so I wasn’t too sure I am also trying to lose weight so I hope dairiy doesn’t hinder my weight lost goals

          • Peggy Holloway

            Some people are more sensitive to dairy. You have to determine your personal tolerance. I’ve found that I’m better off if I eliminate nuts – we are each different in how various foods affect us. I can have butter and cream and quality cheeses without restriction. One of the aspects of the ketogenic diet is that one is so easily satiated that “as much as I want” is actually not a large volume of food because everything is so nutrient dense and high in satiety and energy supply. The higher my fat intake, the slimmer I get and I don’t eat this way for weight reasons but because of my severe insulin resistance which means I’m very intolerant of carbohydrate. My entire family suffers every symptom imaginable – we could be a case study for Dr. Perlmutter with everything from full-blown Type II Diabetes to ADHD and depression. My kids, who are very susceptible to mood disorders seem to have received a genetic double-whammy as their father has Parkinson’s. They are trying valiantly to get him to go grain and sugar-free, but he is a MD (internist) and so brainwashed from having trained in the 1970s and 80s. Well, more than you wanted to know, but just a pep talk that the benefits of a ketogenic diet go beyond weight management – and often weight normalization is a happy side effect.

          • ri

            i definitely see all the other health benefits associated with going low carb hope your family jumps on board with you! its hard to convince people who really need to give up carbs to do so my mom is diabetic and she wont give up her breads and sugars she does watch her intake but i feel like shes somewhat addicted

          • Peggy Holloway

            Most of my family members have gone low-carb and seen the benefits- daughter, son, sister, brother, and significant other. My kid’s dad is the resistant one and the one with the serious health issues despite or maybe because of being a medical professional.

          • David Perlmutter

            Glad to hear that Penny. So nice to hear of an entire family finding success and good health. If you like, share your story with me at Success@drPerlmutter.com, so that I may share it here on the website. I’d love to share the story of a whole family like yours.

          • ri

            my brother in law is also an internist and hes very glutenous -I would never try to give a doctor health advice because I feel like they think this is all bogus and we should eat from all food groups in moderation-meh Ive stopped trying to explain the health benefits if somebody is unwilling to learn and make a change whats the point?

          • Judith

            Hi all,
            I thought I’d add my 2 bits worth about dairy. There are folks who tolerate raw milk well, because it hasn’t been heated and the natural enzymes haven’t beed destroyed. No sensitivities. Cultured raw is even better. So, raw milk (is safe – know your source) is a food in it’s natural state, especially when it comes from real dairy cows. I loved going back to full fat milk, butter, cheese, eggs, real foods, etc. I have been able to get off all kinds of mood meds as well. Yay, real food, high animal fat, moderate protein, low carb (no gluten)!!!
            Good luck everyone and thank you Dr. Perlmutter! (I’ve told my Rxing/research doc about your work.) It’s great to see a doctor who isn’t afraid to tell people to eat animal fat!

          • ri

            congratulations Judith!!!that’s exactly how I eat now (with the occasional indulgence) and I love it! I do try to moderate dairy from milk butter and cheese but I do eat eggs almost daily and I too love eating real foods!! its wonderful and this is the diet lifestyle I can stick to because its just easy and not very restrictive I get around eating gluten foods very easily so nobody thinks im on some strange diet. I respect Dr Perlmutter and Dr Davis immensely for having the courage to write books which are not met very well by everyone including those in the health industry. But they are truly life changing books and very happy for you for getting off of mind altering mood drugs! wish you good health :)

  • Kev

    In all the marathons I have run I have yet to see a barefoot or minimist runner (vibram 5 fingers etc) finish in front of me, or someone on keto adaptation. This will be interesting and I wish you good luck. When is your marathon?

    • olaf

      Hi Kev, I’m estimating it could take me up to 2 yrs. Late this summer I’m planning to run a couple of half marathons as part of my training and maybe a marathon as well – but this won’t be the attempt to break my grandfathers time. These will possibly be run in Montana, as we want to film them, want to come along?

      • Kev

        Hi Olaf, many thanks for your reply. Would love to come along but im in the UK. I run the London Marathon every year as it’s my local marathon. I have always been interested in Keto adaptation and think it would suit ultra events & maybe Ironman, which is my main interest. It’s cool to correspond with athletes that are actually taking the plunge into KA and running marathons. I eagery await the outcome and hope it brings good results.

        • olaf

          Thanks Kev, the trailer for the movie will be released hopefully later this month, but I’m sure there will be an opportunity for us to run together at some point. Best of luck in London.

  • David Perlmutter

    Olaf, Thanks for participating in our discussions!

    • olaf

      My absolute pleasure

  • Melanie Ballard Fahey

    I’m currently training for my fourth MS 150 cycling event and wondering how to do this without carb replacement fluid or “carbing up.” Can you give us endurance athletes a few pointers about how to do this successfully?

    • Peggy Holloway

      Melanie – the century ride my partner and I did in September was an MS event! We ate our usual high-fat, low-carb meals(dinner for me was a salad with blue-cheese dressing, a fatty cut of prime rib of which I ate around 4 to 6 ounces, and some green beans with butter) the previous day, got up that morning, had some coffee with heavy cream (these days I would probably do butter and MCT oil), then took off. The day was very hot and windy and our route was in an area called “The Loess Hills!” It was not a misnomer! The crucial factor was that we had been in ketosis for many months (for me, years) and had trained all season in ketosis. Once you are well ketone-adapted, don’t “cheat” but stay firmly in ketosis. We’ve found we are not ever hungry and have abundant energy. And, as I’ve said, we aren’t exactly youngsters!

      • Melanie Ballard Fahey

        Hey Peggy! Thanks for the info! I road 40 today on “bullet-proof coffee” and felt great! Happy cycling!

      • Gord

        I am a marathon runner who is used to long training runs, I have been trying the low carb, high fat lifestyle and no grains, since the end of November and it has been difficult as I used to be a carb addict, I think I have it figured out except for the protein part, I think I still take in too much protein so I am cutting back in that area, I struggle to get past 21k in my training runs, I have done several 23 and 25 k runs and anything over 21 is a real struggle, no muscle or joint pain but I feel absolutely drained of energy and struggle to continue, I even felt a little light-headed and wobbly at the 24k point of my last long run, what is going on??, I just discovered MCT oil and tried it by taking 2 tablespoons straight up but got heartburn and nauseous feeling in my tummy, so now I take it with a glass of coconut water just before my run, I just did a 10k run after drinking coconut water mixed with MCT oil and felt great but I wonder if it will help with the energy for the longer distances

  • Ernesto Burden

    I’ve been on a ketogenic diet for two months now, and I am looking to run my 10th marathon at Boston this year, hopefully under three hours (last year was 2:58:43). I’ve experimented with extensive carb depletion and with carb fasted long runs and training in the past, but never run a marathon at race pace in ketosis. Am strongly considering going for it – have no desire to go back to sugary Gu, even for one day, but am leery as well. Don’t want to see my A race of the season crash and burn. Any advice or words of wisdom you have, Olaf, or Dr. Permultter, would be greatly appreciated!

    • olaf

      Ernesto, I would recommend you stick to your guns if you believe you’re truly in ketosis at this point. I ran my best half marathon last summer, it felt easier than ever and the recovery was the quickest I’ve experienced. I have not run an official marathon, but plenty of 3hr long runs in training plus some high intensity interval workouts that lasted 2-3 hrs – all done on an empty stomach and never once run out of fuel.

      Let me know how it goes, good luck.

      • Greg

        Olaf I really appreciate your story and certainly wish you the best. I am a family doc and have enjoyed watching patients change their lives by going low carb. I average a diet of about 80 gms of carbs a day and am a triathlete. Looking forward to a summer that finishes with a 70.3 (Half Ironman) I feel better than ever. Often to not eat before training. I intermittent fast once a week and on that day often swim and run and feel totally energized. However I doubt at 80gms of carbs a day that I am at all ketotic. Do you think I am sitting square in no man’s land??? Cheers.

        • olaf

          Greg, thanks for your interest and support, I greatly appreciate it. If you can train well on a day where you don’t eat beforehand, as you mention, you must predominantly be burning fat for fuel. I had never been tested until I did a VO2 Max test at the UF Performance Center back in December 2013, if you truely want to know how much fat you are burning, that’s a way to go. However, through my own self study and what I was experiencing in my running performance, I knew I had to be burning fat. I honestly don’t know how many grams of carbs I eat per day, I just stick to the right foods and stay away from the culprits almost religiously. This is pretty much how I eat: 5-7 eggs a day, add as much olive, coconut oil and butter to each meal as possible, green and above ground vegetables as Dr Perlmutter recommends, all meats but I do find eggs are my preferred protein and will often have them for both b’fast and dinner, very little fruit and always with heavy cream, macadamia nuts and a fair amount of high fat cheese. These days I eat only two meals per day as I have found that intermittent fasting seems to be a real key to staying in ketosis. I hope this helps, let me know.

          • Greg

            Olaf. Thanks again for making yourself so available and public. You have already inspired me to set some very specific goals regarding low carb endurance. While I do feel I am kind of in the “grey area” at about 80 carbs a day your words were encouraging about what I was doing. I thought I would give you an update. As I said, I intermitent fast, so I last ate at supper time yesterday. After some early morning office work I came home and got on the treadmill for 65 minutes, then I shovelled snow for 20 minutes. (Anyone named “Olaf” must know what kind of work shovelling snow is) then I went and swam 1.5 km to be followed by a 11.3 km skate ski that took about 1 hour 5 min. At 4 pm today I ate for the first time since yesterday and I feel great. My energy level was high and no light-headedness, In the back of my mind I was using today as a test day and I am very encouraged to continue. You and many others in this blog were influential. Cheers.

          • olaf

            Greg, that’s great news. I found I only had to be disciplined for the first 3-4 few week of intermittent fasting, eating only twice a day now is just normal.

      • http://www.ernestoburden.com/ Ernesto Burden

        Olaf, thanks for the response and encouragement. Had good experiences with it so far. Am pressing on!

        • olaf

          Ernesto, glad to be of some help, let me know how you progress.

    • Joe C

      Ernesto, I’ll be running Boston as well and hopefully fully keto-adapted by then. Started LCHF in October and I’m up to 16 mile long runs, no nutrition during. Feeling great! I definitely think running Boston without carbs is entirely possible, and keeping your awesome time. 2:58 is extraordinary. At 49, I’m hoping to stay under 3:30. Good luck with training and hope to see you out on the course.

      • http://www.ernestoburden.com/ Ernesto Burden

        Joe, cool, stay in touch and perhaps I’ll see you there. If you want to connect via twitter, dailymile, etc., my blog at http://ernestoburden.com has all my contact info and I’ll be tracking my training there as well.

  • klaus1

    Is it safe to be on high fat and low carb diet such as ketogenic diet if one has hypothyroidism? My mother has been diagnosed with Parkinson’s disease and she has had hypothyroidism for many years (on synthroid).

  • Runner52

    Hi Dr. Perlmutter, Thank you so very much for your groundbreaking research. I lost my mom to Alzheimer’s in 2009. I am on day 10 of the grain brain diet. I do believe gluten was causing problems for my digestion and brain. Being hypoglycemic, I am struggling with fatigue from not eating sugar. Also, I am a lean athletic runner and do not need to lose weight. Not sure what to eat more of. Any suggestions?

  • Kimberly

    I am an endurance athlete who just finished reading Grain Brain yesterday. I will start the 4 week plan of action on Monday. I also will start my 18 week marathon training plan for my upcoming marathon the following week. I am excited about getting on the low carb high fat diet. But I am concerned that I will be attempting too much at the same time. Am I crazy for trying to switch my diet while training? In reading some of these posts I just don’t think I will be going as extreme in my diet (like pork fat). I am a stay at home mom so I normally eat breakfast and then take my kiddos to school and then do my workout. Is that ok-it seemed like some said they only drank coffee before working out. Also should I just start not taking GU’s on my long runs from the beginning?
    I guess I just want a little advise. I am really putting a lot of hopes on a certain time for this marathon.
    Thank you for all your help.

    • olaf

      Kimberly,what I have encountered is that while you are in transition to ketosis, you don’t want to overdo the exercise, because you may not be getting all the energy you need to do that yet. Once you transition to burning fat, you then have to let the body adjust to doing it at higher and higher intensity levels so that you can still use fat for fuel while exercising which will take some time. I did intermittent fasting regularly at the early stages, this seemed to speed up the adaptation to burning fat during exercise, in fact eating just twice a day is now my daily routine. But definitely get rid of the GU’s and any other sugar, otherwise you’ll be going backwards. Best of luck.

      • Kimberly

        Thank you for responding! So since I am already training for this marathon I think I will wait until it is over to go full on the diet. I have cut out gluten but will wait to cut out the carbs.

        • olaf

          Kimberly,I don’t know your 18 week marathon training schedule, but if you are doing a lot of long slow running for some weeks, that should work beautifully with the transition to ketosis. It’s mainly if you are doing a lot of high intensity training, you may find it harder. I see it this way, the sooner you switch to fat burning the better. One of the biggest benefits I finding now, is that my recovery rate is going through the roof, so you might just find a little setback in training now will be well worth it in the end.

  • Cathy Valenti

    Today I just finished a 10.8 mile trail run, with a total of
    over 3600 feet elevation gain and loss. I did this last year. My training
    (running miles) was about the same both years – I’ll call it sufficient. The
    difference was that I am three weeks in to the Grain Brain Diet. I had coffee
    and a few ounces of cheese before I started, and that was all. I was thrilled
    to find out I took almost 45 minutes off my time last year when I ran it (3:25
    last year, ~2:41 this year). There were some differences – it was minus 7
    degrees last year when we started, and 22 degrees this year. I am seven pounds lighter
    since I’ve been following the grain brain diet. We did the route in reverse,
    although the trails and distance were the same. I felt better running it this
    year, and I can’t tell you all how happy I am right now!

  • Joe

    I’ve been on the no grain diet for about 2 months now. I feel good and have lost about 8lbs. I’ve reduced my caloric intake with 65 to 70 % of my calories coming from fat. I have found that my heart rate, however, is now much higher when I exercise. Is this a common reaction for the body as it transitions from a high carb diet to a high fat diet?

  • David

    I’m a multiple Ironman finisher, age 54. Registered to do another this Fall and beginning to ramp-up the training intensity. Just switched to the Perlmutter diet and really struggling with distance training/energy. But going to stick with the low carb/high fat diet; get the ketosis strips glowing bright red, and see how this goes. See lots of posts about people being able to do 2-3 hours runs…but Ironman will take 11 hours for me. Hoping this works. Feels impossible right now. Any tips from anyone would really be appreciated.

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  • runnergirl

    I’m an endurance runner that is about a month in to a keto diet and I have been experiencing extreme calf cramping ever since. I’m very frustrated, even considering dropping the diet, because I can’t seem to find a way to relieve the cramping in my legs. Do you have any advice? I have tried eating carbs promptly before my runs and then eating keto the rest of the day and that doesn’t seem to help either.

  • Lori Hicks Lemaster

    I am so glad to see this blog post. I am fairly new to the Grain Brain diet (about a month) and it is going very well. I feel great! But, unlike a lot of the other commenters here, I do find that I don’t have as much energy when I run and was wondering if I should add bananas/some other high carb food prior to a long run? I have a half marathon coming up in a few weeks and would like to know what to do. Thanks!

  • Paige Kelly

    Hello, I am a triathlete that trains from 1-6 hours a day depending in the day. I am trying out your book and have been following the sample meals however I find I am hungry between meals or even after eating the sample lunch. As an endurance athlete do I need more than what the book calls for or will my body adjust to the smaller amount of good foods? If I do need more where should I be getting it from? Thank you!

  • Jerry

    I see where a group of experts from Hahvahd School of Public Health says to cut down on saturated fats and substitute polys. Que pasa?

  • JP

    Did you run the Marathon. What were your results? What did you eat before and after? Thanks.

  • Rich

    I’d be curious to hear suggestions for someone who is allergic to eggs. Simply replace with other meats / dairy?