Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
6 Dec

How to Train for a Marathon

Leading into this post, I promised myself that I wouldn’t try to dissuade people from running marathon(s) or any long distance races. I already do that plenty in other posts, so today’s is geared toward the folks that simply are going to run a marathon or marathons, regardless of what I say. I know these people exist because I used to be one. Running a marathon can be a huge bucket-list accomplishment. With that in mind, when people write in to ask me about training for a marathon, I think about what I would do in that situation knowing what I know now. How would I train to do the least damage and get the most benefit? Truth is, if I put my mind to it, and you had elite level potential, I could most likely train some of you to win the thing outright, but that’s not what this post is about. This post is about finishing the race without embarrassing and/or hurting yourself. It’s about accomplishing something big, something special. It’s about training for a decent, respectable showing in a marathon. One (or two, or three if you must) and done.

To be an effective marathoner – or even to just finish one – you have to be an effective fat burner. It is the beta-oxidation of fat, both dietary and stored body fat, that provides much of the aerobic energy you will need to maintain reasonable pace for 26.2 miles. I mean, 26.2 miles is a whole lot of miles. When you’re driving somewhere and the sign says “26 miles” to your destination, you think “That’s kinda close, but kinda far.” Now picture that on foot. Yeah. Good luck doing that as a fully dependent sugar-burner. Fat’s the ticket, and if you have spent the requisite few weeks reprogramming your body to derive most of your energy from fat while at rest and at low level of activity (through your PB diet), you will be primed to access fat while training.

With that in mind, you’re not really training for a marathon, per se – you’re training your body to become more efficient with its energy so that you can run a marathon. You’re actually reapportioning how your body uses various types of fuel at different activity levels. Thus, training for a marathon comes down to three primary goals:

1. Achieve mitochondrial biogenesis and optimality.

Increasing the number of mitochondria (biogenesis) will spread the aerobic workload – the beta oxidation of fats and some glucose/glycogen– across more cellular power plants. Improving the number and efficiency of your mitochondria will allow you to do more output (running) with less reliance on glucose and/or glycogen as a primary fuel and more reliance on fat (input). In effect, this will increase your “miles per gallon.” Only instead of filling the tank with gasoline, you’re using stored body fat.

2. Increase the amount of fat burnt relative to carbs at a given work output.

Glycogen depletion is the defining point of “hitting the wall,” so you want to avoid the wall as long as you can. Remember, it’s 26.2 miles. The more fat you’re able to burn and turn into useable energy, the less glycogen you’ll go through. Muscle glycogen storage is very limited, and whether you’re a sugar-burner or a fat-burner, you’re still going to store the same amount of glycogen – it’s the rate at which you deplete it that counts. If you can access fat more efficiently and use fat for work that would normally require glycogen, you’re winning. If you can train to use fat for higher workloads, you can increase or maintain the intensity without dipping too deeply into your muscle glycogen.

3. Increase your aerobic threshold.

The aerobic threshold is the maximum level of output at which you are still relying primarily on the aerobic, or oxidative, energy pathways. As long as you stay under that aerobic threshold, you can train yourself primarily using fat to generate ATP energy (and your high fat diet plays a key role here, too). Once you cross that threshold you start burning more sugar. As you get further into anaerobic territory, however, you’re burning mostly sugar – liver and muscle glycogen. Sugar burns faster (and hotter), and it doesn’t last nearly as long as fat. So if you can increase your aerobic threshold, you should be able to increase the intensity of your runs without dipping too deeply into your glycogen stores. Ideally, then, a prospective marathoner will train to increase his or her aerobic threshold (we’ll save the ANaerobic threshold discussions for another day). That way, you can save the glycogen for the finish line, when it really matters.

One way to start out is to simply keep your heart rate at or below 65% of your max on longer runs (and this might eventually become 70-75% of max as your training benefits accumulate). To determine a person’s aerobic threshold, I find the most intuitive way is to have them run “long” (6-12 miles after a few weeks of sufficient low level training) runs on back-to-back days on fewer than 150 grams carbs per day. If you can complete both runs, both days, without adding back extra carbs, you’ll know you haven’t been dipping too deeply into your glycogen stores. If so, that’s your aerobic threshold pace. Remember it.

As for a specific training prescription, here’s what I’d do every week, beginning at least 12 weeks before the event and generalized for the widest possible audience:

1. Two to three slow aerobic threshold runs.

These should be easy runs performed just below or at your aerobic threshold at the type of pace you can easily maintain. If you are just starting out from little run training, these sessions can be long hikes with easy jogs thrown in. These are great opportunities to just log mileage and improve fat oxidation efficiency without too much stress, where you can actually think about stuff other than the run (hey, maybe even work through some personal issues). For improving mitochondrial efficiency and stimulating mitochondrial biogenesis, these aerobic threshold runs (and your Primal Blueprint eating strategy) will be your bread and butter – the kind of low-level training I referenced in the post on improving mitochondrial efficiency through exercise.

To really promote fat oxidation, limit your carbs or even go into these runs in a slightly fasted state. When you begin dipping into glycogen, or hitting the wall (which might come soon-ish since you’re fasted or slightly carb depleted), back off. You want to stay away from the anaerobic pathway. The length of these runs will depend on your baseline endurance, and you’ll soon be able to stay under the aerobic threshold for longer (which is the whole point!). I would add a mile each week to the longest of these runs.

2. One interval session, followed by an active recovery day.

Run intervals one day a week – alternating repeat 400 m one week, 800 m the next. Walk or jog for two minutes in between. For the 400s, start with as many as you can comfortably do the first week and add one each week until you are at 12 intervals for the workout; for the 800s, work your way up to 10. On a scale of 1-20 with 20 being the most intense, keep the intensity at about a 14-16. It’s not an all-out sprint, because, well, good luck sprinting 800 meters multiple times, but this is at faster than your intended marathon race pace for sure.  The next day, go for a walk or hike or go bike somewhere. Don’t go climb Half Dome or anything. Keep it pretty light.

For the intervals, you’ll definitely want to carb-load the day before. Slam the sweet potatoes and yams, about 400 carb grams worth, since you’ll purposely be blasting through your glycogen that next day.

3. One race-pace run.

Here, you’re trying to emulate the race pace without going the actual distance. It’s necessarily higher intensity than your regular runs, just at or slightly above your aerobic threshold. It’s going to be tougher, too, with some glycogen depletion. Don’t expect to pull out your iPhone and check Facebook in the middle of it.

Start with at least two or three miles, or a bit more than whatever length your threshold runs are, and add a mile each week (minimum).

If you plan on doing this barefoot or in minimalist running shoes, be absolutely certain your lower body is acclimated to it. A marathon is a long way for someone whose feet, calves, knees, and hips (with all the connective tissues that go along with said joints and body parts) have only been spending cursory time exercising without protective footwear. Review my post on making the barefoot transition and confirm that your ship is in shape.

Well, that’s what I’ve got. Remember, this is just general advice for the wider public. If you were my client, I’d tailor the training to you, but you’re not. For what it’s worth, this is how I’d train myself I were crazy enough to get back into running marathons, because it’s effective, it’s low-cost, and it’s actually a fairly healthy way to go about training for one.  I mean who doesn’t want rockstar mitochondria?

Any runners out there? Any marathoners? How do you train?

Next time, I’ll discuss how to fuel a marathon while staying Primal. And yes, it’s very possible.

Whew, and I didn’t even mention the phrase “Chronic Cardio” once. I’m pretty proud of myself. Thanks for reading.

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. Didnt eat primal yet when I ran my first marathon but the biggest problem I and most other people seemed to have was getting the legs to move after ~30km. I would recommend a few 3h runs before the race just to get your body used to moving for longer than 2h periods.

    Robin wrote on December 6th, 2011
  2. I ran 2 full marathons and 1 half marathon in a 30 day period this fall. A 3:42 full, a week later a 1:36 half and three weeks later a 3:43 full (trying to BQ to no avail, I think I was tired).
    I trained this summer running two days a week. One long run (tempoing every 2 miles) and one medium run. I ate as primally as possible and avoided as much sugar as possible.
    My recovery was ridiculously amazing, as protein is key in recovery.
    Of course I ate sweet potatoes, bananas, and definitely cookies (if I can’t eat cookies after running 20 miles, when can I?), but not too much.
    The key for me was nutrition, not over training (seriously, two days a week running most of the time and taking those runs at a close to race pace) and tempo runs (sometimes when I could get in a 3rd run). I have a 1.5 yr old and 2.5 yr old which is why my training was limited. That’s why I had to take every advantage I could, and nutrition was one definite way. I don’t think there is any other way to train for a marathon than by eating primally and keeping the running to a minimum.

    abs wrote on December 6th, 2011
    • awesome!

      did you lift? I’m trying to keep lifting and train for a marathon.

      did you train 20 mile max long runs before the first full?

      how do you define tempo run? vs race pace ?

      thanks for any info you can supply

      dale wrote on December 2nd, 2014
  3. Wow! What a great day for this post. My GF just asked me to run in a Marathon with her for Gasparilla (Tampa, Florida) it i in March and it gives me time to follow the lead. I have only once run in a 5K 25 years ago. This is just something on my list. Thanks for the Post.

    Bradley wrote on December 6th, 2011
  4. tough mudder > marathons

    protandim wrote on December 6th, 2011
  5. Mark, I’m with the others; we need a post on training for and dominating 5Ks!!

    dado wrote on December 6th, 2011
  6. I’m going to run a marathon soon, after having trained in five fingers fueled by sweet potatoes and not running more than 2 days a week – one all-out sprint and plyometrics day, and one mega-long run. I’ve always considered my long runs “play”. I run them slowly and enjoy the scenery. I’ve seen too much in the paleo/primal community hating on marathoners, but as you have detailed here, LONG DISTANCE RUNNING SHOULD BURN FAT. It doesn’t have to tap into glucose-burning and stress responses. Running 26.2 miles shouldn’t feel like Crossfitting for 3 hours straight.

    This post made me so happy :)

    Mary E. Clark wrote on December 6th, 2011
  7. How To Train For A Marathon: Don’t.

    Samantha Moore wrote on December 6th, 2011
  8. Just ran my first marathon in November (wasn’t primal) but have recently been considering moving more toward primal eating. Can’t wait to read your fueling post.

    maria wrote on December 6th, 2011
  9. I just finished my sixth half marathon on Sunday after going primal for 40 days. I beat my last seattle half marathon PR by 10 minutes! I did however eat carbs for the three days prior to the race. I still wonder if my success was from the primal diet or the three days of carbs. I didn’t even train as hard this year! I pretty much only run twice a week due to injury and I supplement with other types of cardio, such as spin class.

    jenn v wrote on December 6th, 2011
  10. I’m with Kelly – if you don’t take carbs during a run of this length, you’re going to get the glucose you undoubtedly need from your muscle protein instead. Why waste away the muscle that you’ve been Lifting Heavy Things so hard for. The carbs won’t hurt you in that context, with your insulin sensititivy at the max. They go straight to the engine!

    Daniel wrote on December 6th, 2011
  11. Mark,

    Thanks for the tips! It’s good to look at it more as conditioning your body than training to run. I don’t run marathons, but I’m about to start preparing for a 15k, so I’ll definitely incorporate some of these suggestions.


    Alykhan wrote on December 6th, 2011
  12. I ran a marathon a couple years ago for my bucket list and hated it. I love the half marathon distance though. The full is just not for me. I got sick during training and a couple weeks after the race and couldn’t kick it for a few weeks. Not worth it! Now if I run (which I still like even though I burned myself out on it w/ the marathon training) I keep the distance to less than four miles. Sometimes I miss the mental high of running longer but I haven’t gotten sick nearly as much since I cut back so I still keep it short. When I ran 40 miles a week I had much more trouble with weight gain and carb cravings. 20-25 miles per week seems like the optimal amount for me though now I walk a lot more. My joints in my feet are finally healing from all the damage I did to them years ago!

    Michelle wrote on December 6th, 2011
  13. I use Phil Maffetones 180 minus your age for your max heart rate for training runs

    rb wrote on December 6th, 2011
  14. I’m interested in how one can eat primal and run a marathon. I thought one needed alot of carbs to burn

    rb wrote on December 6th, 2011
  15. I approve of this topic!

    Curley bro wrote on December 6th, 2011
  16. Great topic and so true!
    I too believe in Maffetone holistic method and find it very paleo/primal compatible. Actually it was his book that showed me importance of whole food diet and I switched to paleo thanks to it.
    This combination of low/moderate carb diet and low stress/no pain training helped me to improve my marathon time by 36 minutes in one year (from 4:01 to 3:25) and, importantly, improved my health.
    Now, I like running and love my weekend long runs, but I do it for the fun of it and at very easy pace – no chronic cardio and no need for carb loading.

    peter b. wrote on December 7th, 2011
  17. I don’t see what’s wrong with long distance running- we evolved to be hairless, bipedal and sweaty for a hunting tactic that resembles modern-day ultra-running.

    Harry wrote on December 7th, 2011
  18. I am a primal triathlon coach and I find that it is VERY hard to convince people to let go of the sports nutrition. People are AFRAID to go without it and convinced they won’t survive if they aren’t constantly eating. We recently had a client switch to primal while training for a marathon and he lost 15 pounds and PRed.
    You can do a lot as a fat burner, and when you learn to do that it makes carbs feel like rocket fuel! Carbs are a great tool for when you need to go fast, but most people use them for every single workout when it’s not necessary.
    Most athletes I know maintain or gain weight when training for long events because the exercise makes you hungrier and because the carbs go through the roof. Plus they are too tired to cook! Training for a marathon is hard, not because of the mileage. It’s hard because of all those other reasons…makes you hungrier, makes you too tired to cook, makes it harder to maintain control of your diet.
    Lots and lots of endurance athletes train so that they can eat bad food. It’s very hard to convince athletes that exercising doesn’t “allow” them to eat junk. I wish more people would realize that running a marathon doesn’t make you a healthy person if you are doing it overweight and on a terrible diet.

    Jessica wrote on December 7th, 2011
  19. Okay, I know this is not the same thing at all, but I tried Zumba yesterday, and I think I’m addicted. Is there any way I can justify it and not admit that it’s chronic cardio? Do you think it could count as my all-out effort every 7 days?

    rabbit_trail wrote on December 7th, 2011
    • Had to google it, but that looks more like “play” than cardio.

      Jon wrote on January 18th, 2012
  20. I’ve always wanted to run a marathon but never thought I would be able to complete it. I’m bookmarking this for the summer.

    Joe wrote on December 7th, 2011
  21. Five running sessions a week seems like a lot. I trained for a half marathon (my first) last year with one long run a week, and a few sessions in the gym (weights, not cardio). As an over 40 female who is not ideally built for running, I find running more than twice a week to be tough on the old joints. I also make sure that the majority of each run is on soft surfaces.
    How would you adapt training to someone who needs to train less often?

    Indiscreet wrote on December 7th, 2011
  22. Thank you for this post! I don’t run marathons, but I really enjoy longer trail races and off road triathlons. I’ve been training and racing “clean” (primal diet, no carb loading, no sports drinks, no GU) for the past year and I am amazed at the results! I feel great during and after races and I am faster than I ever thought possible!

    Eddie wrote on December 7th, 2011
  23. Is anybody running or doing triathlons primal-ly and competing at a pretty high level? I started doing crossfit after finishing ironman wisconsin in september, and am having a mental struggle with the strength(weight) gains compared to an all aerobic plan. I say that long term health is my focus, but my fast run times are slowly drifting away (16:45 5k summer, 18:00 Turkey Trot),but i dont want to panic and revert back to chronic cardio.

    afeltz wrote on December 7th, 2011
  24. Sorry- should have noted i’ve been 80-90% primal diet for 18 months or so

    afeltz wrote on December 7th, 2011
    • Are you using crossfit running workouts? or just lifting? How often are you lifting?

      Still eating your veggies? Careful of all those nuts!

      Remember, in the end, the first goal is to be healthy and fit. Even if it is at the expense of being fast.

      But I don’t think you need to lose speed.

      Rhabdo wrote on December 7th, 2011
      • I’m mostly doing 4-5 WODs a week (mix of low rep strength work) and running at lunch time 4-5 days per week, but only 30ish miles. Not doing many intervals based on crossfit fatigue, so i guys its more of a question of balancing weights and intervals while getting enough recovery. And yes, lots of veggies, pretty much no nuts or fruit, some dairy (cheese). I could blame the beer, but i refuse to :-)

        afeltz wrote on December 7th, 2011
        • You might want to check out the programming on the Crossfit Endurance site ( They recommend about 4 WODs per week balanced with around 3 endurance workouts per week (1 interval, 1 Tempo, 1 longer distance). For multisport, they recommend I think 4 endurance workouts max (maybe 5), I am primarily a runner so not as well versed on that. Check it out though because they guy who runs it has done Ironman and they have several multi-sport athletes successfull using the program.

          Erik wrote on December 8th, 2011
  25. I have run 9 marathons so far and I am planning to run number 10 this January. Most of the earlier marathons were done fueling with sugar, like gels and such. After I switched to a primarily primal diet I found that I didn’t need the packets of gel on my run. It was quite amazing to run the full 26.2 without feeling depleted. Just in case I run out of fuel during the run I have a small bag of dates that I bring with me. Most of the time I don’t even need them!

    Peter Koch wrote on December 7th, 2011
  26. Mark, I love the whole primal thing. I don’t embrace it fully, but try to do what I can! One question – I love doing spin classes at my gym. In a sense they are very much an interval training class (especially the RPM classes). I like to do 2 or 3 a week, 40 minutes each. Is this overdoing it?

    Gamini wrote on December 7th, 2011
  27. this inspirig detail info will help each and everybody,those who want to be a part of marathon.

    2012 Custom Printed Calendars wrote on December 8th, 2011
  28. Good stuff in this article. So far, I have only run a half marathon but that one was up a 13,000 ft. mountain here in CO and back down. However, I think I would continue to keep some emphasis on strength and mobility training that is so often neglected in the endurance world. I know I did when I was training for my half and my hamstrings and upper body noticed it during the run when they were subjected to that much up and downhill running. Maybe we are talking about a slightly different beast there but I still believe many endurance athletes negelect their strength training in favor of the endurance they are training throughout the week. One of my favorite resources now ever since that experience has been the fine folks at Crossfit Endurance ( They share our belief in Paleo and many of Grok’s approaches to fitness including avoiding chronic endurance or LSD (Long Slow Distance), as they call it. Their method has guided many athletes through marathon and beyond to ultra distances on minimal endurance training but maximal, short and intense, training.

    Erik wrote on December 8th, 2011
  29. Paul,

    Thats funny, I ordered the book: Born to run, the other day :-) looking forward reading it even more now.

    Thanks for the link, great article and even though I’m already sold to the whole barefootrunning idea I haven’t heard of the 100 up exercise. I will try it out for sure!


    Kristian wrote on December 8th, 2011
  30. I ran my second marathon (my first finish) this year in 7 hours. While I’m happy for the finish, I think I’m capable of a MUCH better time. I do have another marathon that I signed up for in May 2012, so the discovery of The Primal Blueprint and now this blog post are pretty timely for me. I’m looking forward to trying a more “primal” training method for my next marathon.

    I have a question about aerobic threshold that I have a feeling is pretty intuitive, but I just want confirmation…

    Right now, when I’m at 70-75% of my max heart rate, I’m only at a brisk walk. As I follow a Primal diet along with Primal fitness (long, slow exercise, lift heavy things, sprint once in a while), will I improve on this, for example, be able to jog lightly in this heart rate range? It seems like as I get healthier this would happen, but as I said, I need confirmation.

    Thanks fellow MDA readers!

    Phaedra wrote on December 9th, 2011
    • I know this is a delayed response, but for those that come after us I will offer this: If a brisk walk is 75 percent of your max then over time this will improve until you can jog or even better. I switched from to this method of training and dropped from running all my runs at 9:00 min/miles to brisk walks, then to 14 min miles, then 13, then 12 then 11. So now I am about 11 min/mile keeping my HR at 133. Eventually this should improve even more.

      David Yazel wrote on April 29th, 2013
  31. i ran my one and only fueled by primal. pre race meal was baby food with protein powder and it was the best! i made my own goo using pureed dates. plain witha bit of salt was great. worst experience involved coffee, peanut butter and dates in a slurry that came straight back up…

    deanne wrote on December 10th, 2011
  32. I think if Dean Karnazes can run 50 marathons in 50 states in 50 days. Running a marathon every now and again will be ok:)

    Marc wrote on December 11th, 2011
  33. Does anybody have any input as to a general range of mileage for this type of training.

    For instance: for race pace Mark suggests adding a mile per week for at least twelve weeks. So are we looking at 15-20 mile race pace efforts here?

    Also what distance should the longest aerobic threshold run be? I know they should be dictated by effort to some extent, but I don’t understand the total mileages here…i.e 15 mile race pace + 15 mile AeT in one week?

    Tim wrote on February 2nd, 2012

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