The Great Ketogenic Ironman Experiment – Can You Go Low-Carb And Be A Fast Endurance Athlete Without Destroying Your Body?

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Articles, Low Carb & Ketogenic Diet

For the next 12 weeks, I am going into self-experimental, bio-hacking guinea pig mode in preparation for Ironman Canada in Whistler on August 25.

It's called the “Great Ketogenic Ironman Experiment”, and in just a moment, I'm going to spill all the beans for you. I'll show you a sample ketogenic training diet, a sample minimalist training week using time-saving underground training techniques, and reveal the secret weapons I'm going to use to enhance my fat-burning and training results.

But first…why the heck would YOU even want to try a low-carb, ketogenic diet for something like an Ironman triathlon? Or a marathon, Crossfit training routine, hard swim workouts, multi-day cycling stage race, or anything else that is energetically demanding and requires moderate doses of endurance?

There are three main reasons for using a low-carb, ketogenic diet.

1) Metabolic superiority of using fats as a fuel.

Peter Attia really gets into this in the excellent blog post on “Ketosis – Advantaged or Misunderstood State?“, in which he explains how being in a ketogenic state vastly enhances your lipolysis (fat burning efficicency), your aerobic capacity and your muscular endurance, including significant increases in aerobic power and efficiency in several groups of elite athletes (e.g., Olympians) across multiple physical tasks maximally stressing the aerobic system. Go read his post to dig into this stuff.

For this very reason, the U.S. Defense Advanced Research Projects Agency (DARPA), has been investigating ketogenesis as a secret weapon for boosting soldiers’ mental and physical performance under battlefield conditions. Why? Because as a soldier's blood glucose drops, they became confused and sometimes ended up shooting their own side. So they tested a highly ketogenic fuel source on rats and found it boosted physical and mental performance – and the rats became much healthier, lost body fat, had lower levels of triglycerides (fatty acids) in their blood and lower blood sugar levels, with zero harmful side-effects. That same fuel is now under development for soldiers, although I have no clue why they don't just give them canteens full of Medium Chain Triglyceride (MCT) oil, since it does the same thing.

2) Health and longevity advantages of controlling high blood sugar.

To illustrate these advantages, I scanned and pasted here a compelling image from Life Extension Magazine (I don't know about you, but I want to be around to see my grandkids, and considering my genetic testing revealed higher risk for Type II Diabetes, I doubt that shoving any more gooey gels and sugar sports drinks into my gaping maw is going to do me any favors).


3) Mental Enhancement

This is also a brain-hacking technique that goes way above and beyond smart drugs. Ketones are an potent source of fuel for your brain neurons, and when you're ketogenic, you have higher levels of brain derived neurotrophic factor and an enormous upregulation in brain neuron regeneration, focus and mental acuity (once you get over the “hump” of those first 10-14 days of making the fuel switch). If you want to learn more about why ketones are a a high power brain food, listen to this “Marvel of Ketone Science” interview.

Finally, I'm not just messing around here and doing this Ironman at a slow, aerobic pace. Instead I'll be attempting for an Ironman World Championship qualification, and a total time of 9:15-9:45. We're talking pain cave stuff here, with lots of hard anaerobic efforts thrown in – no lolly-gagging – a hard and heavy swim, 300-400W power efforts on the bike sprinkled throughout a 112 mile ride, all finished off with a 26.2 mile run (marathon) in 3:00-3:15…


What Is Ketogenesis?

Great question.

Here's the deal: I'm not even going to try to comprehensively explain this when so many other resources already exist. Here are the best 4 resources for you to become a ketogenic ninja:

1) My recent low carb and ketogenesis podcast on Jimmy Moore's Livin' La Vida Low Carb Show (in which we also tackle all the questions that are probably going to end up as comments on this post anyways, such as “Aren't You Concerned About Your Thyroid” and “How Does Your Body Make Glucose If You Don't Eat Carbs”, etc., etc., etc.).

2) Peter Attia's excellent series on “Ketosis – Advantaged or Misunderstood State?“. Put on your geeky propellor hat and scientific wading pants and go read it. He's good.

Low carb diet for athletes3) Any of the other podcasts I've done with Peter, including: “How To Turn Yourself Into A Fat Burning Machine By Fasting For 24 Hours Then Going Out And Do Monster Workouts Without Bonking” and “Is It Possible To Be Extremely Active and Eat A Low Carbohydrate Diet?“.

4) My Low Carbohydrate Diet For Athletes package (pictured left), which includes a complete low carb for athletes meal plan with fat adaptation, low carb maintenance, race/event week and race/event day blueprints, my low carb guidebook and 24-7 access to a low carb forum (warning, this program isn't necessarily ketogenic – it has carb re-feed days and stuff like that – but it's a good resource nonetheless).


The Great Ketogenic Ironman Experiment Overview

OK, let's get down to the nuts and bolts. Here's how this ketogenic protocol is going to go.

I'll be implementing a 100% ketogenic diet (meaning I'm keeping my blood ketones at 1.0 millimolar or higher) along with…

-weekly Talking20 blood measurements to make sure I'm not killing myself, and also to get some interesting data on what happens to thyroid, inflammation, testosterone, cortisol, etc. when combining ketogenesis with hard training.

-daily Ketonix breath ketone measurements to make sure I'm keeping my ketones above 1.0 millimolar (whoopee for smart scientific sounding numbers!)

-daily Sweetbeat HRV measurements (that's “Heart Rate Variability” – read this for why I do it)…

Hypoxico's Intermittent Hypoxic Training protocols

Jay Schroeder's EVOAthlete electrostimulation, isometric and overspeed training protocols

-All the other “underground training methods” I outline in this article…

-And a bunch of other secret weapons I'll tell you about below…

In addition to putting weekly updates on my Facebook page and video updates on my upcoming phone app (launches June 3), I'll be discussing the results of the experiment at this year's Ancestral Health Symposium during my panel with Jimmy Moore, Robb Wolf, Mark Sisson, and Jamie Scott. And that symposium will be exactly one week before I actually take things into the deep, deep trenches and try to qualify for Kona at Ironman Canada.

Warning-unless-you-wantWarning: unless you want to seriously “F-up” your body (e.g. adrenal fatigue, joint damage, metabolic derangement, etc.), I do not recommend you combine ketogenesis or low carb diets with any form of hard or heavy training unless you're willing to utilize the strategies you're about to learn. I'm not even 100% sure that with all the “damage control” I'm personally going to be doing that I will not experience medical issues while doing this experiment. But SOMEBODY has to find out if elite performance and ketogenesis are compatible, so I'm diving in.

Clear? OK, let's keep going.


Sample Weekly Ketogenic Ironman Training Diet

Here's a sample of what I'll be eating. Basics: 50-100g carbs on an easy day, 100-150 carbs on an average day, 150-200g carbs on a hard and heavy day, along with lots of medium chain triglycerides to keep my body in ketosis. So this isn't calorie-restricted ketosis. It's high-fat, high-calorie ketosis (that's Lesson #1 for you to ensure you don't destroy your metabolism with stuff like this).

-Breakfast: Piping hot cup of “Upgraded™” organic, mold-free Upgraded Coffee blended with unsalted, organic KerryGold butter and Medium Chain Triglyceride (MCT) oil, with a touch of vanilla powder and Upgraded™ Chocolate Powder.


(if you don't like coffee, try this “Ketogenic Kale Shake” which is roughly adapted from Dave Asprey's recipe)…1 bunch of steamed kale…2-4 Tbs grass-fed butter…1-2 Tbs of MCT oil…1 tsp sea salt…2 Tbs of high quality protein powder…1-4 tsp apple cider vinegar…Coconut milk to desired texture…Herbs (i.e. cilantro, parsley, oregano, etc. – great for cleansing gut/liver too). Steam kale about 5 minutes to reduce oxalic acids then blend with all ingredients (add protein last so you don't kick protein's ass).

-Mid-morning: TianChi with vegetable juice (I prefer my cleansing cocktail of cilantro, parsley, carrot, lemon and ginger juice, with a few pinches of Himalayan Sea Salt). If this takes me out of ketosis, I'll leave out the carrots. Sorry, Bugs Bunny.

-Lunch: Large kale salad with extra virgin olive oil, avocado, olives, walnuts, sardines and nori OR my world-famous sexy ketogenic smoothie (kale blended with MCT oil, brazil nuts, cinnamon, coconut milk, Upgraded™ Chocolate Powder, stevia and an avocado).

-Pre-Workout Snack: Shot of X2Performance with 2-3oz MCT oil.

-Dinner: Grass-fed beef, liver, sweetbreads (yes, that would be thyroid gland), wild salmon, etc. with roasted vegetables.

Rrrrrr – back it up. Liver and sweetbreads? Yes. Here's the 30 second elevator pitch: your liver needs glucose to convert T4 to T3 so unless you give yourself extra liver support and thyroid support by eating organ meats and sweetbreads, you'll mess up your thyroid on a diet like this.)*

Snack: 2-3 tablespoons coconut manna (AKA nectar of the gods)

*Here's the rest of the reason, taken straight from this Chris Kresser/Chris Masterjohn podcast:

Chris Masterjohn:  Yeah, and I think you highlighted something important there that there are a lot of classic symptoms that go beyond the blood tests, and you know, I think even if you don’t see the changes in T3 and reverse T3, there are other mechanisms.  For example, if you have increased liberation of free fatty acids beyond what you’re able to utilize, there is some evidence that the free fatty acids will accumulate in the nucleus of the cell at a high enough concentration to inhibit thyroid binding to its receptor, and that will cause all of these symptoms of the metabolic effects, including the high cholesterol, but it might not show up as changes in thyroid hormones in the blood.  So, I think if you see those classics symptoms, if you see high cholesterol and low sex hormones, for example, I think those are good clues in addition to T3 and reverse T3 that might signify that an increase in carbohydrate intake might be needed, but I have an anecdote that I think is pretty interesting to share from Nutrition and Physical Degeneration, Weston Price’s book.

Chris Kresser:  Yeah, let’s hear it.

Chris Masterjohn:  He says:  “For the Indians of the far North this reinforcement” — he’s talking about reinforcement of nutrition for pregnancy — “was accomplished by supplying special feedings of organs of animals.  Among the Indians in the moose country near the Arctic circle a larger percentage of the children were born in June than in any other month.  This was accomplished, I was told, by both parents eating liberally of the thyroid glands of the male moose as they came down from the high mountain areas for the mating season, at which time the large protuberances carrying the thyroids under the throat were greatly enlarged.”  So, what he’s saying is when the moose were about to reproduce, they naturally went into a kind of hyperthyroid state where their thyroids were enlarged, and the people there would harvest the thyroid glands so that they could reproduce, and as a consequence, most of their children were born nine months after the moose mating season.

Chris Kresser:  Wow.

Chris Masterjohn:  And what the indicates to me is — I mean, it’s difficult to interpret it because he doesn’t go into great detail, but I think what we might be seeing here is up in the Arctic circle — and these are the inland people, they’re not seacoast, so they probably don’t have a lot of iodine in the diet, they certainly don’t have a lot of carbohydrate in the diet.  It seems like they, as part of their natural adaptation to their environment, they supplemented with thyroid hormone so that they could convert their cholesterol to sex hormones so that they could increase their fertility, and I think what we’re witnessing is perhaps a natural acknowledgement that under those certain conditions where you have an extremely carbohydrate-restricted diet, you may need supplemental thyroid hormone in order to maintain that fertility. 

There you have it folks. That's how I'm going to maintain my yummy, fat-fueled, sweetbread-laden fertility. You can check USWellnessMeats if your local organic farm can't get you sweetbreads and liver.

Not a fan of the taste? You can actually use liver and thyroid supplements, but you need to be very careful with the source of that dessicated liver and thymus gland. Standard Process thyroid is decent at around two tablets a day and then for liver look  for Argentinian and organic. NOW Foods dessicated liver powder is good for this, at 1 rounded tablespoon per day.


Sample Week of Minimalist Ironman Training

Due to time constraints and my desire to avoid chronic cardio overtraining, I'm following a complete 8-10 hour per week minimalist Ironman training protocol, while implementing all the Underground Training Techniques you learn about in this post and this post. This includes extreme isometrics, hypoxic altitude training, overspeed, high intensity intervals, super slow weight training, cold thermogenesis, heat acclimation, greasing the groove, and electrical muscle stimulation.

Here's a sample week so you can see what this kind of stuff looks like. It may look a little overwhelming at first, but once you establish your daily habits and patterns, it's pretty easy to fit this stuff in.


-60 minutes yoga and meditation.

Cold thermogenesis (20-30 minute cold soak in 45-55 degree water).

-Full body foam rolling, 10 minutes inversion table, mobility work for any neglected areas.

-Stay off feet.

Tuesday :

-5 minutes hot-cold contrast shower.

-Swim 10×100's using Wetronome to decrease 100m time by 0.2s per week.

-Run “Hurricane workout”, 10×30 seconds at 10mph and 10% incline. All performed with deep nasal breathing (I highly recommend BreatheRight strips for doing hard workouts/races with nasal breathing).

-Commute bike to gym and back for workout above (total 30 minutes cycling).

-All day: 5 pull-ups every 1-2 hours, entire work day is at standing workstation.


-Superslow lifting: 5x 30 seconds up, 30 seconds down full body lift (e.g. Squat, Overhead Press, Seated Row, Back Extension, Pull-Up). All performed with deep nasal breathing.

-Bike – 8-10 30 second overspeed efforts of 120-150rpm. All performed with deep nasal breathing.

-Isoextreme back foot elevated lunge 2 minutes each side, followed by 1 Russian Lunge every 5 seconds for 2 minutes, then repeat for opposite side (performed in sauna). You can find most of these isoextreme exercises on this YouTube Channel.

-All day: 5 pull-ups every 1-2 hours, entire work day is at standing workstation.


-Swim 50's and 25's sprints using Finis front mounted swim snorkel with hypoxic CardioCap.

-Litvinov 400m run repeats as 15-30 dumbbell swings or front squats to 400m uphill or flat run. All performed with deep nasal breathing. If tired, no run, but just easy, fun Elliptigo on trail.

-Commute bike to gym and back for workout above (total 30 minutes cycling). All performed with deep nasal breathing.

-All day: 5 pull-ups per 1-2 hours, entire work day is at standing workstation.


-10 minutes inversion table.

-30 minutes suspension trainer workout.

-Easy bike to sauna at gym for 5×20 second on, 5 seconds off isoextreme lunges, 5 minute isoextreme wall squat, and standing hamstring folded dollar bill drill 10×30 seconds on/10 second off. All performed with deep nasal breathing.

-All day: 5 pull-ups per 1-2 hours, entire work day is at standing workstation.


Electrostimulation 30 minutes quads/hamstrings + 60-90 minute tempo intervals ride using Sufferfest training videos and Hypoxico altitude generator

-If time: easy swim drills 30 minutes in cold river (kind of a combined cold thermogenesis with training).


-Run 60-90 minute tempo intervals on treadmill or trail.

And yes, compared to disappearing from my kids, work and social life for a 5 hour bike ride on a Saturday morning, slipping into the garage “pain cave” for a quick Hypoxico session is far superior. 


My Ketogenic Secret Weapons

OK, here's the stuff that I'll be relying on for the next 12 weeks – the things that will make your life far easier, your training way more productive and your body way less likely to get metabolically damaged if you doing low carb triathlon training. I call these my “Ketogenic Secret Weapons”.

1. Kion Coffee with MCT oil and Grass-fed Butter

Take some Kion, organic & mold-free coffee and blend with grass-fed (KerryGold is a good brand) butter and Medium Chain Triglyceride (MCT) oil. This stuff keeps me in a ketogenic state with me having to feel like gnawing my arm off in hunger halfway through the morning.

Kion Coffee Beans must always conform to the following five health parameters – and less than 1% of coffee worldwide makes the cut:

-Kion starts with the healthiest possible green beans. We test organic coffees from all over the world to find the green beans with the highest antioxidant levels – and we work to maintain those levels all the way through the production process.
-Kion Coffee is always organic. Less than 3% of coffee on the planet is certified organic. At Kion, we will never tolerate pesticide-soaked beans, or grow our coffee in fields that are doused with herbicides.
-Kion requires “near zero defects”. Only the highest quality, specialty grade coffee beans meet our standards. We rigidly test for toxins and never select beans that are chipped enough to risk an uneven roast, or beans that may contain undesirable microorganisms.
-Kion Coffee never contains mold. Ever. When searching for the freshest coffee possible, mold cannot be tolerated.
-Kion Coffee is grown sustainably, then hand picked and hand selected. We only choose the BEST coffees from the BEST organic, sustainable farms in the world, where we have a direct relationship with the farmer. The farms that grow Kion Coffee use production practices that are good for the planet, good for the coffee crop, and good for the people who grow the coffee, both economically and ecologically.

The addition of the MCT oil provides a readily available fuel source brain mitochondria, and may help you to excrete toxins from the brain, while the fat from the butter and the oil improves the ability of mind-stimulating terpenes and caffeine in coffee to enter your brain, along with potent coffee-based anti-inflammatories such as cafestrol and kawehol. And adding a touch of vanilla powder and Chocolate Powder makes it all the more heavenly.
Just call it “The Kion Triathlete” breakfast.

2. Oxaloacetate

If you’re using extreme isometrics or high-intensity interval training and experiencing the massive lactic acid build-up that occurs in the local muscle tissue during a set, then you should know about something called “oxaloacetate”.

Strap on your geek hat for a second.

Most chemical reactions in your body take place in a series of several steps. In chemistry, the rate (or velocity) of a reaction with several steps is often determined by the slowest step, which is known as  rate-limiting step.

A significant rate limiting step of converting lactic acid into glucose (a really, really efficient way for your body to get glucose for hard efforts) is the conversion of the molecule Nicotinamide Adenine Dinucleotide (NAD) into Nicotinamide Adenine Dinucleotide Hydrogenase (NADH). So what does this have to do with oxaloacetate? In studies, acute oxaloacetate exposure enhances resistance to fatigue by increasing NAD to NADH conversion and allowing lactic acid to get recycled and converted to glucose at a much higher rate (16).

As a matter of fact, along with calorie restriction (which isn’t much fun, really), enhancing your Cori cycle efficiency is also one of the ways that you can significantly increase the enzyme AMPK, which you learned earlier in this book can upregulate mitochondrial biogenesis and improve both carbohydrate and fuel utilization.

Basically, this means that you can become a complete lactic acid metabolizing endurance beast if you take about 100-200mg of oxaloacetate in supplement form 15-30 minutes prior to a workout that includes either high intensity intervals, super slow training, or isometrics.


3. X2Performance

The main ingredients that X2Performance contains that directly help the purposes of ketogenic training are…

-d-Ribose, which allows you to rapidly regenerate ATP, even in the complete absence of carbohydrates (especially important since high intensity training depletes your total adenine dinucleotide pool much faster than long slow distance training, and you need that precious pool to make ATP)…

-Pinitol, which enhances uptake of cellular energy, even in a state of low insulin, which you'll be in if you're following a low-carb or ketogenic diet…

-Low doses of caffeine, which enhance free fatty acid utilization…

For anyone who wants to geek out on how loading with d-Ribose also allows you to more easily tap into your body's own free fatty acids as a fuel, read neurosurgeon Jack Kruse's excellent article that reveals the truth about carbohydrates and exercise performance. I'll be slamming a shot before my workouts, and also before and during Ironman, and X2Performance has offered you the code BENGREENFIELD to get $10 off a case of the stuff in case you want to do that too.

4. UCAN SuperstarchUCAN-Plain-Tub-300x347

UCAN Superstarch is for anyone who wants unflavored, 100% pure fuel – in a non-GMO, slow release form for that allows you to use far less carbohydrate and burn significantly more of your own fat as a fuel. SuperStarch causes a very low release of insulin and results in an extremely stable blood sugar profile compared to sugary gels, sports drinks, powders or  energy bars.

This stuff puts your body in the ideal performance state and make you more metabolically efficient, thus allowing you to burn more fat as a fuel. To listen to an excellent interview about how to practically use this, and why burning more fats during exercise is good, listen to this interview with Peter Attia.

Also, for more scientific information on Superstarch, read: “A Technological Breakthrough in Sports Nutrition Innovation: a white paper by Professor Jeff Volek, March 2009″...

…or for a less “sciency” explanation, read this article that appears in Feb 2012 Men’s Health magazine.

I'll be using this during a select few long rides and runs, and of course, quite liberally during the race itself.


How I'll Be Tracking & Testing

Of course, it wouldn't be an experiment if I wasn't gathering data, right? See, I did take a little bit of college at least, even it was in North Idaho.

1. Metron Ketone Breath Testing

That weird tube pictured on the right is a breath ketone monitor. It's brand new, cutting-edge stuff developed by medical device manufacturer Akers Biosciences to detect levels of acetone in your breath, an indicator that your body is burning fat as its energy source, rather than carbohydrates


A Metron breath ketone monitor

It's just a simple breath test can be performed anytime, anywhere. You get a measurement in 3 minutes, and – most importantly – there's no blood testing involved. I'll be doing enough finger-pricking as it is.

This is the same thing my fellow low carb blogger and podcaster Jimmy Moore has been using to test his ketones during his N=1 weight loss experiment, during which he's lost 78 pounds so far (in one year).

2. Talking20 Blood Testing

In the video How To Test Your Blood Anytime, Anywhere In The World, you learned about Talking20, which is disrupting health as we know it by merging biology with technology to deliver personal health data in a way that I think may actually trigger a personal health revolution.

Here’s how it works:

You send in a few drops of blood on one of their kits, and you’ve opened the gateway to everything happening inside you, anytime you want it.  Talking20 is using mass spectrometry to analyze its blood samples, the same technology used by NASA and the Environmental Protection Agency use to conduct their studies of very small samples taken from all over on (and off) the planet. So you can run 100′s of blood tests off a single, convenient drop of your dried blood.

I think this stuff is going to literally blow the roof off personal biohacking and the ability to peer into your personal health and performance in real time as you test anytime, anywhere in the world. For the purposes of the Great Ketogenic Ironman Experiment, it's going to allow me to test every week without driving to the lab and giving oodles of blood.

If you want to try it, you can get your blood tested by Talking20 in the USA by clicking here or internationally by clicking here.

3. SweetBeatHRV Measurements

In the episode “Everything You Need To Know About Heart Rate Variability Testing“, I introduced you to a cool little phone app called the Sweetbeat.

For SweetBeat HRV monitoring, you need:

-The SweetBeat phone app + a wireless Polar H7 chest strap.


-The SweetBeat phone app + a regular chest strap + a ”Wahoo” wireless adapter

Since heart rate variability testing tracks the strength of your nervous system and can be a key sign of overtraining and metabolic distress, this will be a way to track how beat up my body is, and how my nervous system is responding to carbohydrates (or lack thereof, more specifically).

Interestingly, there may also be a correlation between ketogenesis and the “low frequency” number you get when measuring your HRV. I was alerted to this fact in a recent reader comment (copied and pasted below):

tom's comment

Oh yeah, that's kinda small, huh?

Here's the full conversation from the comments section on my What Kind Of Damage Happens To Your Body After You Do A Hard Workout, Triathlon or Marathon?

Tom – Some days I have a very very high VLF. say up to 80% of the power. Research is unsure what this means but could be related to diet, stress etc.  I have noted that if I take serial readings across a morning I am fasting, till 12 noon usually, VLF gets steadily higher until I eat. It also seems to be higher when I am ketogenic, so could be of interest to you. Also, in regards to your Ketogenic experiment, I take my ketone readings with a blood monitor multiple times a day, I have found from my research that I can consume huge amounts of carbs in and around training (mostly in the form of waxy maise starch) and sweet potato, and still be ketongenic (ketones 1.5-2mmol) the next morning. But If I overdo it on protein and fat later on in the evening and eat my last meal later than say 8.30 pm I have no ketones the next day, down to 0.3 or similar. Food for thought…

…The significance of VLF is still up for debate. I've read many theories including infection (this one I have noted in myself, I have predicted my last 3 infections with a sudden surge in VLF noted 2-3 days prior to symptoms). Also there is evidence it is linked to energy expenditure, which could be highly linked to the thermogenic and energy burning effects of MCT/ketogenesis. Such as –  This correlates well with my findings in ketogenesis.

 If that spiel was all greek to you, go listen to this podcast episode on heart rate variability testing (or read the transcript). Go ahead, just do it. Once you get it through your head, none of this HRV stuff is too scary, and makes intuitive sense.


How YOU Can Follow & Learn

This is going to be an exciting adventure, and along the way, I'll be eager to answer all your questions about low carb diets and endurance training, any of my “weapons” or training and diet methods listed above, and anything else you want to know.

The very best way to follow this entire experiment will be by 1) following the BenGreenfieldFitness Facebook page and 2) grabbing the brand new, free BenGreenfieldFitness phone app, which will be released on June 4 (don't worry I'll send out an email about it, so be sure you're subscribed to my free newsletter). I'll be releasing photos and updates to the Facebook page and insider videos and audio updates to the phone app…

…in the meantime, leave your comments, questions and feedback below.

Ask Ben a Podcast Question

75 thoughts on “The Great Ketogenic Ironman Experiment – Can You Go Low-Carb And Be A Fast Endurance Athlete Without Destroying Your Body?

  1. Lanier Nelson says:

    Ben how did the ironman go on the keto diet? I have been doing a keto diet for my Ironman as well and my ultimate goal is to go sub 10. The race is in a week and a half. how did the race go for you? I mean how did your body feel and what was your time?

  2. Scott Chesrown says:


    Got any advice on how to get through the hump of the fuel switch? Been 10 days for me, use pretty much all your suggestions, but still struggling during workouts feeling like I have any energy. X2 helps, but still not anywhere near my normal performance? And when your body finally makes the switch, is it more gradually or do you just go into a workout one day and feel like you are back to 100%? Hope all is going well with you.

  3. Leonard Shaw says:

    Can anyone point to a single successful example of any world-class or major league athlete using a keto deit for any sustained period of time? How many Gold medal winners? MVPs? Heismans? Any single athlete at all in the history of the world?

    It would, incidentally, have been an easy experiment for Gary Taubes (a former boxer as I’ve heard) to have done. And very convincing. And to have included in his book.

    1. Check out my interview with Mark Sisson and read his book re: Dave Zabriskie!…

  4. Tom Murphy says:

    Concerns of using d-ribose while in ketosis.…
    Personally, I have been on a low carb/ketosis diet over the last year. I just started taking d-ribose but read the above report and became worried. Especially, because my urine immediately became foamy (a sign of proteinuria). Did you ever encounter any similar issues?

    1. the use of D ribose has never been an issue for me in terms of ketosis… Especially if you're physically active, I wouldn't worry about it too much. However, I can treat this in more detail if you call it ino the podcast. Here's how: Go to and keep it under 1 minute

  5. Mathew_King says:

    I just bought some sweetbread, googled a recipe and found out that there is a lengthy preparation. Do you really soak them, blanch them, take off membranes and all that stuff? Can I just throw them in the pan and make them? How do you make yours?

  6. danco1212 says:

    Are you back to doing re-feeds or staying keto with the intentions of long term to experiment using the PPP?

    1. I'll be answering this question in the post-Hawaii Premium podcast!

  7. Ron Renaud says:

    Hope the low carb thing is going well, any updates ? You really stick your neck out for all of us.

    1. Update coming in the next episode with Brock!

  8. renee4ironman says:

    Hey Ben
    I actually started this whole "fat adapted" diet about 1 week ago. Had the Bulletproof coffee every morning this week but not this morning… just wasn't the same! I actually haven't had a lot of the symptoms they mention you may get in the first 10-14 days so that's great.
    My question…. one of the things Dave Asprey talks about as well as John Smith, Debbie Potts do intermintent fasting. Do you do this as well?

    1. Yes, I fast about 12 hours for every 24 hour cycle!

  9. Dan Ordoins says:

    How are things going with the ketosis and have you gotten any follow up lab results to see progress?

    Thanks and please do keep us updated.

    1. I'll be going over all this in the upcoming premium podcast from Dan!

  10. TraderOPG says:

    Hi Ben, please update us on how your oxaloacetate experiment is working or not working on your lactic acid / athletic performance when you can. Thank you! Michael

  11. Michael K. says:

    Hi Ben, I was just wondering if your experiment with oxaloacetate (upgraded aging formula) is working or showing any signs of success. Thank you!

    1. It's going quite well – I notice a difference when I take it before ANY workout that produces lactic acid! I use 2 capsules 30 minutes prior.

      1. TraderOPG says:

        Hi Ben, thanks for letting me know (and my apologies on the double comment)! When will you be writing about your experiences with Oxaloacetate? I am curious on trying this product, but would love to read more first — most importantly about the safety of it and how much (in your opinion) it boosted your performance.

        1. Go over to – this would be a perfect question to ask for my upcoming podcast I'm doing for premium version of app…see the thread there on this…

  12. Freddie says:

    Ben, do you supplement with electrolytes other than magnesium as suggested by Phinney/Volak/Attia?

    1. Yes, I do trace liquid minerals every morning, like this:…

  13. ray says:

    The study about oxaloacetate only specified slow-twitch muscle fibers gaining benefit, is there anything out there to increase endurance for Fast-twitch fibers? Besides transformation training, I mean.

    One last question, I noticed you do a contrast shower (hot/cold) Before a workout, Normally its done afterwards to help assist in recovery, any particular reason why you do pre-workout instead?

    1. Oxaloacetate is going to work in any environment where lactic acid is being produced….pre-workout cold-hot thermogenesis increases blood flow…

  14. Jeff Meador says:


    So what's your day-before race meal and race-day breakfast? Still 2 sweet potatoes with honey and almond butter? Or now changed to higher fat content?

    1. UCAN with MCT Oil.

  15. Jeff Meador says:

    Ben, how does fueling for the day before a race and the morning of the race look from a ketogenic diet? Your low carb book describes 1-2 sweet potatoes with honey and almond butter on morning of. Should this now be high fat to maintain ketosis? Thank, Jeff

    1. Well there's a difference between low carb and ketosis. But if goal is ketosis, I'd be doing UCAN + MCT Oil. Or just bulletproof coffee, for example.

  16. Clay says:

    How are you going to use T20 since they are not processing as of yet?

    1. I'm sending them cards every week.

  17. Mikki Williden says:

    Wow Ben. Indepth which is fantastic. I heard you talk about this on LLVLC and am super excited to see how it pans out. I consult with a number of athletes re: LCHF and ketogenic diets (endurance athletes) and I don't know that I would put someone on a ketogenic diet over and above an LCHF diet (which I'm a big fan of). Hence why your self-experimentation will be really interesting! Further… your IM training… very interesting! Would be interesting to see how keto + standard training, and 'normal' + minimalist training look separately. Got any training hacks willing to look at this? Good luck!

    1. Well, I've personally combined the two! The main difference I've found is that the keto vs. normal results in A) lower hunger; B) more stabilized appetite levels; C) less bloating/gas; D) lower blood sugar.

      1. Mikki says:

        Thanks Ben. Will keep it in mind.

  18. Jeff Meador says:


    Since I have been strictly ketogenic for the past 2 months, training for Olympic distances this year (not half-IM's), I was listening to your podcast recently on low carb diets. I have a couple of questions on the addition of liver and thymus (sweetbreads). Since my wife won't allow me to cook up liver (she can't stand it :)), I would like to take desiccated liver as well as thymus gland tabs. How much and how often should I be taking these? Last thyroid test I had a month ago showed low thyroid hormones.


    1. You need to be very careful with the SOURCE of that dessicated liver and thymus gland, Jeff, but Standard Process thyroid is decent at 2 a day <a href="http:// (” target=”_blank”> <a href="http://(” target=”_blank”>( and then for liver look for Argentinean and organic. NOW Foods is good for this, at 1 rounded tablespoon per day:…

  19. cathy says:

    I'm anxious to hear how this all works out. I'm am just coming off 7 months of VLC to Low Carb (in and out of ketosis a few times). I have to admit I have never felt worse in my life! It got so bad that as I tried to start eating more carbs I was getting massive heart palpitations, very weak, dizzy, and just a mess. My doctor thinks it may be due to an ammonia buildup of so much sulfur containing food. I am now on a sulfur free- high carb diet, with no animal products. I feel better than I have in 8 months- but I think it's just due to the increase in carbs. Bottom line- I believe in Ketogenic diets, but they are certainly not for everyone! In my case it was downright dangerous…

  20. Tom says:

    Ben, would you and your readers like my 'Keto-Brownie' recipe (patent pending). ?
    Guaranteed and tested and helps maintain ketosis!
    Sorry I am english and I do grams I'm afraid.

    150g EV coconut oil
    30g butter (Jersey grass-fed – so dark its almost orange)
    2 tablespoons of cocoa
    100g of creamed coconut or I guess coconut butter? We don't have coconut butter here.

    Melt these together and let cool a bit (otherwise it will curdle the eggs)

    3 eggs
    70g of gluten free flour, rice flour, or almond meal (from soaked and dehydrated almonds)
    1 medium sweet potato (baked then skin removed and mashed – keeps things moist)
    1 shot of espresso
    2-3 teaspoons of cinnamon
    2 teaspoons of vanilla
    Stevia leaf to sweeten (I grow my own) or a stevia extract if you don't do this!
    Or coconut sap works well. But I don't like em too sweet anyway.

    100-200g of cashew nuts or whatever you fancy.

    whisk all this up and cook at no higher than 160 Celsius (again, no idea about Fahrenheit!)
    any higher and the MCTs can be damaged.
    for approx 20mins, undercooked is better than over.
    Let cool and put in the fridge, they go very fudgey! Gorgeous!


    1. killer! That recipe sounds really good. If you shoot a video or photo of it I can post to and see what people have to say!

  21. Robert says:

    This is seriously awesome, major geek stuff! I totally love the depth. I will be following your adventure and taking notes.

    Lead the charge Ben!

  22. Moray says:

    Ben, this is awesome. Keep us posted

  23. Jake Jaglarski says:

    Very interested in seeing how this plays out. I had a hunch you were transitioning into thinking about nutritional ketosis since you posted that study showing the various substrates that can be used to make glucose (recycled lactate/pyruvate, glycerol, etc.) and then EMF4 from Dr. Kruse. I have a couple questions and comments.

    1. I have been on a cyclical ketogenic diet for the past few months as per Bulletproof Diet recommendations – but I refeed infrequently, I can complete an altered body by science style workout with an elevation training mask on in ketosis while fasted… do you think I'm at the point where I could put this to the test through my Jiu-Jitsu/Judo training?

    2. What do you think about Dr. Kruse and many on his boards claiming it takes about 24-36 months to fully keto adapt? If that is true (not saying it is or isn't), I don't think you'd be close to fully adapted, and thus wouldn't get the full benefits of ketosis.

    3. Check out this forum post from Barry:… I believe there's a lot of merit to this. Maybe you should consume the upgraded coffee (with a metal filter) minus what the recipe calls for (mct oil/butter/upgraded products) and train fasted to up regulate beta oxidation and what not… I'm not as informed as you though, so I don't know what you think about this.

    4. What do you think about excess protein in ketosis?… clinically it seems as though there shouldn't be any reason protein inhibits ketosis, and if it does slightly increase glucose oxidation, couldn't you get around that with mct's?

    5. What are some cheap alternatives to measure my ketones/glucose and any other readings you would suggest I look for? In the very near future (after experimenting with the Leptin Reset as per Dr. Kruse and getting my first WellnessFx test) blogging about and experimenting with full blown ketosis (no refeeds) and it's impacts on martial arts performance – while controlling for all variables….. seeing just how much protein/carbs I can consume while maintaining ketosis, how fasting impacts it, exercise, hell, even sex….. (sorry, sexy back summit is still on my mind, lol).

    Hope this isn't too long, sorry about the length. Thanks for all the great material you put out. Once I get out of this financial rut I swear you, Dave, and Dr. Kruse are all getting a donation or something from me.

    1. Sure, I'd put it to the test for Jiu Jitsu. See what happens! If you're very good with EMF exposure, structured water intake, etc., Jack's 24-36 month idea becomes shortened. I just interviewed him on podcast I'll release soon. I'll check out Barry's post, but I hope to get him on a podcast soon also.

      Also, I train fasted quite a bit. I'll often have 5-7 hour periods during the day where there are 60-90 minute training sessions throw in with zero fuel before, during or after.

      You are correct that excess protein in inhibits ketosis, and I'll be keeping a close eye on that in my case because it's a fine line between cannibalizing yourself via inadequate protein intake and eating so much you go out of ketosis.

      There are no cheap ways to measure ketosis, Jake. You get what you pay for. Blood glucose monitors, on the other hand, are a dime a dozen.

  24. WT says:

    What % of the time will you be in ketosis? 100-200g carb days will knock you out of ketosis for at least a couple of days, eh?

    1. Unless you're an Ironman triathlete. ;) I burn that amount of carbs by 9am.

  25. Jerry says:


    Couple of questions.

    1) Am I missing something or are you not already on a 150g or so carb/day diet? I thought you'd been running about this level for some time. Or am I mistaken? If not, how is this much different than what you've already been doing for a while now?

    2) Re. thyroid concerns. I've looked into ketogenic diet quite a bit. I haven't seen the concerns over thyroid that you mention. I don't even think Dr. Peter Attia or Dr. Phinney and Dr. Volek agree. In fact, I know Phinney and Volek don't agree. They call it a myth based upon all of their research and studies – and they address Kresser directly. They believe that caloric restriction is the culpret for low thyroid. Here's a podcast where they talk about it.… With that said, let's assume that thyroid is a concern…or one wishes to mitigate the possibility so we don't have to decide who's right…is there a way to accomplish the same thing without eating liver and sweetbreads?

    1. Jerry…

      1) I am already eating 150g carbs or so and stray in and out of ketogenesis. Now I'm going full blown ketogenesis and also taking in way more MCT's to keep ketones high. So a few tweaks. I'm basically going from cycling low carb to constant 12 weeks of keto.

      2) Based on my own T3 being ROCK BOTTOM, I put some credence in what chris kresser (and others) have had to say on this issue. I know of no other way to mitigate this issue than to add offal and thyroid into the diet. It's why vegans and vegetarians shouldn't go near this strategy in my opinion.

      Big picture is that I'll be able to determine performance metrics on vs. off keto, especially for higher performing endurance athletes.

      1. Danny J Albers says:

        Hi Ben, from experience I can advise there is a large difference between producing ketones by adding coconut oil and "skirting the edge", and having your muscles preferentially use ketones over stored glycogen…

        My initial impression when reading your food plan is you are stepping into the range we call low carb limbo. Not enough carb to fuel your plan, not low enough carb to have your muscles fully using ketones over glycogen (or at least for most of their energy). Its a no man's land between the two.

        I am highly interested and will follow your results and actually have no problem being proven wrong, but your meal plan as designed strays far above the carb allowance nutritional ketosis usually recommends so I am not sure its a valid test as it seems more like the Jaminet version of ketosis over the Phinney/Volek approach.

        Do not get me wrong, I am a huge fan and do not think ketosis is the ideal approach for everyone, but I see big red flags here and wanted to just toss them out there for your consideration…

        Best regards

        1. Tom says:

          I have been doing a similar experiment to Ben for a while now and I have found more and more that the amount of carbs matters much less than the timing. My body now preferentially produces ketones, or so I believe.

          If I do a very hard long session, I can get away with 50g of carb per hour during the session (in the form of WMS) 50g straight after the session and 150+ later on in that evening.

          My thoughts on this are that if my glycogen stores still need filling then my body will use this to fill them and when its done start producing ketones again.

          I may have been knocked out briefly, but I am back in again by 7am the next day.

          However, if I eat late, or eat a bit too much protein on a day that I haven’t trained as much and I have missed the window so to speak, then my ketones will go from 1.5-2 to less than 0.5 by the next day, that is even with almost zero carb.

          I have learned that gluttony is the enemy of ketones, even in the form of fats. If you over-consume in one go your ketones are done. After a heavy heavy protein load it can take me 3 days to get back into ketosis.

          Also, in regards to your point about the muscles and ketones, I was led to believe and I agree based on my physiological knowledge that muscle use of ketones is highest in the first stages of ketosis, but drops as the brain starts to utilise them, with the muscles relying more on fats.

          I personally believe therefore that the main mechanism of ketones is to stop the negative feedback loop from the brain which induces fatigue due to fuel depletion as glucose/glycogen is no longer required.

          A question to Ben.

          In regards to MCT, I have tried to find some decent evidence on the achievable levels of ketones that can be produced from MCT ingestion and have come up short. I was trying to work out if you could still consume a high amount of carbs (an amount that would produce no ketones) and still get the benefit of producing over 1mmol of B ketone using MCT/coconut. Any thoughts?

          1. From a physiological standpoint, you'll reach a certain point of carb consumption where you would get knocked out of ketosis. That's simply a matter of N=1 testing based on your activity levels, body size, etc. I also have found no data that spells out maximum approximate upper limit for carb consumption that would knock one out of ketosis if you have a high amount of MCT ingestion…

      2. If your T3 is low, it could be you are not eating enough protein. I think 0.8 gm /pound is low for one in training. I usually recommend at least 1 gm /pound for intense training. (that will also support a healthy immune system –challenged during training. ).

    2. Hemming says:

      Hi Jerry,

      From my own personal experience this can wreck havoc on your body if you don't do it properly. That's not to say there is anything wrong with a ketogenic diet (I do believe in a lot of the merits) but you need to be aware of some things.

  26. Shane says:

    Ben whats your daily intake of protein during this period?

    1. I'm at about 0.8 grams per pound of body weight Shane.

  27. Tom says:

    Sounds good Ben, thanks for the mention! I love the HRV stuff, it brings out the Geek in me. I also love the idea that we can understand the body far better than we do, help us achieve our goals and enjoy our lives!

    Quickie, the metron meter, can I actually buy one of those? I'm fed up with all the pin prick testing 3 times a day!

    1. Write to Metron…they're not technically "in business" yet, but they are sending out product: Dan Bourbonnais <[email protected]>

  28. Andrew Foss says:

    Ben, What is your source for Stevia. Everything else is linked.

    1. I like the organic stuff. Wholesome sweeteners is good or the NOW food droplets:…

  29. In the Art and Science of Low Carb Performance I read about an ultramarathon runner who completed ultramarathons without taking in any calories at all. Just water.

    How do you think not eating at all would affect ironman performance?

    1. It would throw you into full catabolism and massively break down your body. It's probably one of the reasons the first guy who ran a marathon died when he finished. I don't recommend.

      1. Aaron says:

        The first guy that ran the (Phidippides) first “marathon” didn’t in fact die the way you think. The is data is grossly negligent on two main factors. The first the distance was 140 miles each way (280 miles total) with the first being in 36 hours over the mountain in Greece (Marathon to Sparta) with no break.

        He then dawned heavy armor and fought the Persians in the Battle of Marathon. Upon completing that he was tasked with running back to deliver the message of the victory (this is where the 26 miles is derived from). He still managed to do this in around 3 hours (history says).

        So after 240 miles of mountain running, battling the Persians in heavy armor, a 26 mile run he died of exhaustion. It had nothing to do with diet.

        I’m late to the game on this and playing catch up on your “experiment” but 100-150 carbs a day is not a ketogenic diet at all. Your body will never be in ketosis at that level. From the reading I have done I have never heard anyone over 30 carbs actually being ketosis.

        This to me would explain why you bonked, you were still very dependent on sugars from carbs.

        Don’t misconstrue any of this, you are a great triathlete and I tip my hat to your ability but your 12 weeks was a waste in terms of ketosis.

        1. I would say 3.0+ mmol daily qualifies as Ketosis. )

  30. Dan Ordoins says:

    Great stuff. Something I have been working on myself using and entering the PPP pathway but with a long term approach allowing more time for the adaption to resonate. Also my approach is a bit more minamilist.
    Can't wait to see your progress and results.
    One thing sense your already starting at a point of thrashed labs how do you think this will effect you and training? Are you healing first before beginning?


    1. Dan…I went over ALL this for a good hour on the last Inner Circle workshop. Highly recommend you join as it would be a lot of writing for me to explain!

  31. Neal says:

    Hi Ben,

    Sounds fascinating! You had mentioned in a previous post about possibly using Vespa for low carb/ ketogenic training. Would this be something to add in during your triathlon preparation? Also, would eating liver do if one can't readily get sweetbreads?

    Cheers, Neal

    1. Liver is definitely different than sweetbreads Nick. I'd do both if you really want to play it safe. Only once a week is fine if it's a big portion, since your body stores a lot of that stuff, like fat soluble vitamins. VESPA is part of the Endurance Pack I use at

  32. @FatSlowTri says:

    My question to you would be about the sweetbreads and liver. I have no thyroid gland (losing it to cancer) which has a number of issues related to energy levels and weight aim. Since I can't "do damage" to something I don't have

  33. Tony says:

    This is exciting! Can't wait to follow the progress!

  34. Matt Keas says:

    That's an awful lot of supplements and stuff to purchase to follow this.

    Is there a shortlist of essentials?

    1. It's not too much. Basically just coffee, oil, oxaloacetate, X2Performance and for racing, Superstarch. But triathlon *is* a spendy sport. ;)

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