Dear Mark: Sprints and Blood Sugar, Resistant Starch as Carbs, PUFA in Coconut Oil, Cycling as Chronic Cardio, and Morning Sickness

CyclingFor today’s edition of Dear Mark, I cover four questions and my wife Carrie covers one. First, I discuss the effects of sprinting on blood sugar in the short term and long term. Next is whether or not one counts resistant starch as a carb in their daily allotment. Third, I identify the actual proportion of omega-6 polyunsaturated fatty acids found in coconut oil. Finally, I give my take on cycling as a gentler mode of chronic cardio relative to running. Carrie wraps things up with a short review of the evolutionary reasons for morning sickness.

Let’s go:

Dear Mark

I see a lot of talk on your site about sprints and how great they are. My question is, what is their effect on blood sugar immediately after a session? As a recovering T2 diabetic living primally for about a year, I hadn’t had a large spike in blood sugar in weeks…until I tried some sprints (jump rope to be precise). I was back to normal about 1/2 hr later.

What’s a normal immediate blood glucose response? Are there any health detriments to blood sugar spikes due to intense exercise?


That’s totally normal, Clark. Sprinting is a particularly glucose-intensive activity. It burns right through muscle glycogen. Sensing this, the liver releases glucose to provide additional fuel for the body; in healthy people, type 2 diabetics, and type 1 diabetics alike, blood glucose spikes after most any exercise, but especially after sprinting. It’s a feature, not a flaw.

The good news is that over the long haul, sprinting leads to improved glucose control. Heck, a type 2 diabetic doesn’t even need to wait more than day to start seeing massive improvements in his glucoregulation. A recent review looked at the blood glucose responses of diabetics (type 1 and type 2) to “brief high intensity exercise,” as which sprinting definitely qualifies, finding that although glucose was elevated immediately post workout, blood glucose control is improved for one to three days following a sprint session.

Keep sprinting.

Hi there, do the carbs in resistant starch count as part of my daily carb intake. In other words if I am trying to stay at 90g of carbs a day and I am taking in 40g of carbs from the resistant starch, does that mean I have 50g left or are those carbs in a different category because they are processed differently?



No, they don’t really count. You’ve still got 90 grams left.

Resistant starch is resistant to digestion by the host organism (that’s you), acting more like prebiotic fiber (food for your gut flora) than anything else. More and more, we’re beginning to understand the necessity of feeding our gut flora, which don’t just impact our digestion, but also our immunity and cognition.

The cool part about resistant starch in relation to digestible starch is that its fermentation yields butyric acid, a short chain fat that actively improves insulin sensitivity and blood glucose control. In other words, it helps you become more tolerant of the carbs you can digest.

Unless you’re heating up your resistant starch past 140 ºF, which would turn it into fully digestible regular old starch, resistant starch doesn’t convert en masse into glucose in the body.

I have a tablespoon of unrefined virgin coconut oil in my tea every morning, because of its health benefits. I was told recently that coconut oil is pure omega-6. Now I’m a little confused, should I be limiting my coconut oil intake like I do nuts or is there something about it’s structure that makes it different?Would you please clarify.



You’ve got a saboteur in your midst feeding you bad info. Coconut oil is almost entirely saturated fat with negligible levels of omega-6. Here’s the breakdown:

91% of the fat is saturated, mostly medium chain triglycerides (fats like lauric acid, caprylic acid, capric acid, and caproic acid which boost ketone production and increase metabolism).

6% of the fat is monounsaturated (the same kind found in olive oil and macadamia nuts).

A lowly 3% of the fat is polyunsaturated (omega-6).

You’re fine. Keep enjoying that coconut oil!

Have you done any more research into specific cardio versus just cardio in general?

In other words, respectfully, I question a little that cycling shouldn’t be separated from the “bad, too much cardio” group. Especially considering that with downhills, stopping at red lights/stop lights and the very social, stop and regroup aspect of it (well, for us amateur riders anyway) – couldn’t it be considered along the lines of sprinting and recovery? I know that on some rides, even centuries, I don’t pedal with full power the whole time, often just coast, and my heart rate goes way down often when I’m just spinning lightly and enjoying the views. Cycling is more a workout for the soul, as far as I’m concerned, and I’m just so torn on thinking that even on long rides (endurance rides) I’m doing myself any harm. It’s the weekend after weekend of long rides that I believe are where one could potentially run (ride) into trouble.

It’s just, I don’t know – given that it isn’t hard on the knees or joints (I ride a triple gear proudly to save my knees!), isn’t hard on the back (if you use your abs to hold your posture correctly!) and is just so social and enjoyable, wouldn’t cycling be considered primal in most ways?


Most research confirms that running is the riskiest of all the non-contact sports. Triathlons afford us a direct comparison between running and cycling injury statistics in the same population. There’s some variance, but the running portion is usually linked to more injuries, as you might expect:

  • An online survey of 212 triathletes found that 50% of injuries were from running and 43% were from cycling. 54% of all injuries were “contusions or abrasions,” which are more likely caused by falling from a bike than tripping over your own feet.
  • Another study found that among 131 triathletes, “high running mileage” but not mileage on the bike was predictive of overuse injury risk.
  • During an actual triathlon, more injuries occur during the run portion than the cycling portion – almost a 3:1 ratio.
  • Traumatic injuries are more likely to occur during cycling, while running is more likely to cause overuse injuries.

The main reason I stopped competing in marathons and switched over to triathlons is because it let me keep up my admittedly insane training and competing load without continuing the destructive trajectory of my joints and overall health. Of course, it didn’t last for long, but I did get a brief lull in degeneration by switching from all running to some running, some cycling, and some swimming.

Cycling is lower impact, but not “no-impact” when compared to running. Overuse injuries do occur, and force does act upon the joint when cycling. One study compared the compressive forces acting on the knee cartilage when running and cycling by measuring the degree of cartilage deformation. Running created greater forces, deforming knee cartilage by 5%. Cycling wasn’t far behind, with 4.5% deformation. These deformations were transient and normal, but you can imagine how they might add up over the course of a session (or sessions). Any misalignment of your tissues – due to, perhaps, fatigue, overtraining, or tight surrounding musculature – will increase or at least concentrate the deformation.

Of course, running form is less linear than cycling form and that makes the runner more susceptible to overuse injuries. When you get tired on a run, your legs start to flare out to the side and your form gets sloppy. When you’re cycling, your form is more “locked in” by the pedals, even if you’re tired. This is probably why cycling is more forgiving to the joints.
Leaving joint issues aside, chronic cardio refers more to the long term effects of repeated medium-to-intense work that causes the heart to overreach and in many cases the heart wall to thicken. A-fib is a minor epidemic now among lifelong CCers.

It is possible to embark on a running program, a cycling program or a triathlon training program that steers you away from CC territory (cross-training, specific weight training, intervals, very slow paced running or riding and, yes, the occasional long, hard slog).

I have never said someone shouldn’t go out for a weekly long ride or run – even a hard one. Or even a few times a week if you’re fit and enjoy that – and can recover fully in between. I am just opposed to the day-in, day-out medium-to-hard effort that doesn’t really improve fitness, but just causes the heart to beat metronomically (not a good thing over a long effort) and to never fully recover. Endorphin addiction (the runner’s high) is not necessarily a good thing.

If cycling is improving your life, getting you out into nature, letting you hang out with your pals, then I’d say it’s worth doing. Just be wary of that threshold where it starts taking away from your life, where you stop noticing the scenery or appreciating the nature, where you start neglecting your friends and family because you’re too sore or sleepy to do anything. It sounds like you know what you’re doing and you’re watching out for the warning signs.

Now, let’s hear from Carrie…

I have read in numerous places that “morning sickness”, as we Westerners know it, simply is non-existent in hunter-gatherer and primitive cultures…in fact they have no idea what such a term even means. These women enjoy easy, robust pregnancy’s with very few issues, and it is my understanding from anthropologists research, that stress is the true culprit that triggers morning sickness for us women living in modern societies. The levels of stress are far fewer, and of a different nature amongst primitive cultures then for us Westerner’s.

So, I am hoping that either you or Carrie can provide some insight on this truly miserable phenomena from an historical/anthropological viewpoint. An exploration into what it means to be preggo, and Primal/Paleo, would be a welcome subject to tackle here on MDA!

Thanks so much!!


Actually, morning sickness is fairly universal among pregnant women, regardless of culture, ethnicity, or diet. About 70% (give or take) of women experience food aversions and nausea during pregnancy, usually the first trimester, and modern research has generally coalesced around the “morning sickness as prophylactic” theory. Even if you’re a pastoral, rural Tanzanian woman eating a whole foods diet, you will probably experience morning sickness when you get pregnant. Food aversions are there to keep potentially toxic or harmful foods or substances out of your body and away from the growing baby. It’s not a perfect system by any means, rather a blunt tool that removes large swathes of food that might actually be harmless or helpful but “fit the profile.”

For instance, wild plants are higher in polyphenols (or phytonutrients) than domesticated plants. Maybe too high, and that’s why we bred them out. In fact, phytonutrients can become phytotoxins at high enough concentrations. Mark has written about this before, but many of the benefits of phytonutrients come from our defensive reaction to them. We want the right amount, not too many, not too little. Then there are the outright toxins found in some wild plants. The end result is that domesticated plants get included in the aversions because our ancient bodies don’t really know the difference, even though they’re probably good for pregnant women.

Some phytonutrients reduce iron absorption. Others, like the ones found in cruciferous vegetables, can inhibit thyroid function when eaten in large amounts especially with concomitant low iodine intake. Wild cruciferous vegetables have even more of these substances. Both thyroid hormone and iron are essential for development of the fetus, so it makes sense that we would evolve built-in mechanisms to prevent overconsumption during pregnancy. Studies have also found connections between high consumption of polyphenols in late pregnancy and negative changes in fetal blood pressure dynamics. A very recent trial even found that polyphenol restriction in the last trimester improved those flow dynamics. Also, many herbal teas are contraindicated during pregnancy due to undesired health effects, and a widespread revulsion against bitter plants would have the same protective effect.

That’s also why pregnant women are more likely to remember people’s faces after just a single introduction, more sensitive to health cues, and more suspicious of “out-group” members – these are all protective measures to keep bad stuff (sick people, dangerous people, certain foods, toxins) away from the baby. I personally find it incredibly fascinating!

But you still need to eat, so what can you do in this case?

  • Make the best choices out of what you can stomach. You need calories now more than at any other time, so eat what sounds good and try to make the best choices possible. So, if you’re craving a sandwich, maybe have it on gluten-free bread. If you’re craving french fries, make some yourself with coconut oil instead of going to McDonald’s.
  • Eat well before you get pregnant. This is your chance to get ahead of the game. It allows you to build up your nutrient stores while you still have your normal, Primal appetite so that eating sweet potatoes for three days straight or living off of avocados and rice when you’re pregnant won’t be such a big deal.

Hope that helps!

Thanks for reading, everyone.

About the Author

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

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68 thoughts on “Dear Mark: Sprints and Blood Sugar, Resistant Starch as Carbs, PUFA in Coconut Oil, Cycling as Chronic Cardio, and Morning Sickness”

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  1. As to resistant starch, please, please PROPERLY ferment the potatoes for 24 to 48 hours before cooking them. There are a host of benefits to this procedure including reducing the carb content of the potatoes and also acrylamide content. Remember that all of the super healthy traditional cultures always fermented grains, nuts, seeds, legumes, and tubers prior to cooking. They often buried them underground in 100% anaerobic conditions. Google search yourself, but take a look at :
    Good luck.

    1. Many people utilize potato starch as a way to get their resistant starches, considering many do not have the space or time to properly ferment everything.

      1. +1. Taking tablespoons of potato starch in cold water is so much easier and faster.

  2. I suffered terribly from food aversions during trimester 1 (I’m currently in the third trimester) – I couldn’t so much as look at an egg and meat and vegetables were generally offensive to me during this time.

    Thank goodness for MDA as I’d been following Primal for around a year (and lost 43lbs pre-pregnancy) so I was in a fit and healthy state to tackle 3 months of refined carbs (with tons of grass-fed butter – not even morning sickness could turn me off that!) and green apples.

    Glad to say that I’ve had a pretty robust and healthy pregnancy so far and if the kicking is anything to go by Junior seems to be pretty healthy too! Looking forward to some Primal co-sleeping and breastfeeding in a month or two when the little one puts in an appearance 🙂

    Good luck to any Primal mums out there!

  3. I’ve been through three pregnancies and never suffered from morning sickness. I went off coffee but never craved anything. Maybe I was just lucky.

    1. That’s really interesting…and yes very lucky! Did you eat a Primal diet during your pregnancies? Any specific tips or takeaways you can offer?

    2. Me too. 3 pregnancies, never nauseous at all. And definitely NOT a primal diet, this was years ago. Very much an “American” diet, although I have always eaten more fruits & veg than the average american. I do remember craving tuna, though! I guess some people are more prone to morning sickness than others.

  4. I love coffee, but with my first pregnancy, I developed an immediate aversion to it, that lasted for the duration. I would have stopped drinking coffee anyway, because of the caffeine, but that made it easy. The same thing happened with the second pregnancy.

    What I didn’t understand, though, was the non-food aversion I developed the second time around: The smell of Play-Doh, which had never bothered me before, and hasn’t since. I couldn’t even be in the room when my preschooler was playing with it. |-p

    1. I was an avid coffee drinker before pregnancy– couldn’t even bear to think about it when pregnant (with twins, *very* bad morning sickness… or all-day sickness, really)– but the morning after their birth, the switch clicked back & I couldn’t wait for my first cup! Hormones sure are crazy.

      I had many food aversions, smell aversions & such. Maybe it was the gluten in play-dough that grossed you out!

  5. Great point, Carrie.

    There are hormonal fluctuations during pregnancy that stimulate the part of the brainstem called area postrema. There’s just no way to get around this other than toxic drugs. I know how 14 weeks of nausea gravidarum feels.

    Another good mention is about the thyroid. I believe thyroid screening should be mandatory before pregnancy (if possible) and in each trimester. The demands of pregnancy put a lot of stress on woman’s body and more women than we believe become hypothyroid.

    This, in turn, may explain some cases of delayed speech (partic. expressive speech) or perhaps even autism in children. Unfortunately, there is no way to know unless you screen moms and correct deficiencies.

    There is a nice study from Netherlands about it.

    1. That’s interesting. My thyroid pretty much stopped working after my son was born (and was probably not working well while I was pregnant). He was diagnosed with Aspergers at age 6.

      1. Cindy, we know there is a strong link between fetal brain development and maternal hypothyroidism. In extreme cases it causes congenital hypothyroidism (cretinism).
        Thyroxine is a pretty heady hormone. No pun.
        I really wish thyroid screening during pregnancy were mandatory, even if pre-pregnancy workup is OK. That should not only include TSH (can be fine) but also free T3 and T4.

  6. These adaptive functions of morning sickness make sense to me, but then it does seem harder to explain the mamas who have none and deliver healthy babies. I always wonder what factors explain these differences–seems like morning sickness signals an area that can’t be explained completely by evolutionary adaptation, nor by dysfunction. I wonder if any of it is about the pregnant body detoxing in some way?

  7. I went off all foods except mashed potatoes during my two pregnancies – beached whale doesn’t come close! Still haven’t lost the weight and wish MDA had been around then.

  8. What about commuting by bike? I do maybe 4 miles a day round trip. Do i have to count that as part of my weekly cardio?

  9. The question about morning sickness nearly made my head spin around! As a woman who suffered through hyperemesis gravidarum (translation: insane, constant puking and nausea, nonstop through pregnancy in my case), I can attest that I had no choice in the matter. No matter what I ate, the pukes would bring it back up. Did you know scrambled eggs can get stuck in your nose?!

    1. O.K. I was just reading your comment and eating my Big Ass Salad and what you said almost had me with a piece of celery up my own nose.

  10. I had a boy and a girl. Both healthy. I had morning sickness with both but much more severe with the daughter. Many food aversions and also cravings. Especially apples! Couldn’t get enough apples!

    1. For me it was oranges, but not until the last month or so. Couldn’t stomach them at first. I was making up for lost time once the nausea finally passed!

      1. Me too! I couldn’t drink enough OJ. It was all I ever drank, which I know is loaded with sugar but I literally couldn’t stop myself. Then in the 3rd Tri I switched from massive OJ cravings to massive milk/dairy cravings. My one food aversion was chicken, prepared any way. 9 months postpartem and I still can’t stand it.

  11. I know that raw potato starch is pretty much 100% resistant starch, but what about other sources–i.e. cold rice? How do I count the carbs in that, since rice probably has only some percentage of the starch as resistant starch. Does the “net carbs” formula (carb grams minus fiber grams) work in that situation? If so, then rice is still pretty high in carbs for those of us limiting carbs.

    1. I wondered this as well. Since the amount of RS that develops when rice and potatoes cool must depend on numerous variables, I doubt you can know how much RS is in a particular serving of those foods.

      1. I’d say if you are eating cooked and cooled foods for the RS, just count the whole food as ‘carbs’ and consider the RS a bonus.

      2. More than likely the question referred to taking RS (like potato starch in a bag) so it’s 100%, no issue about how much in a food.

  12. Nice response on coconut oil. Getting patients out of the framework that saturated fat is bad is still one of the most challenging aspects of nutritional advice!

  13. As far as cycling goes, I’m very much into cycling… My suggestions for keeping it safe and healthy is:

    – Make sure your seat is at an optimal height. If your feet reach the ground, it isn’t, and you’re destroying your kneecaps. Your leg should be fully (but not uncomfortably) extended when the pedal is at the lowest position.
    – The shorter the crank, the better for your knees. (Reduce the range of movement.)
    – Use toeclips or “clipless pedals” (auto-locking mechanism with special shoes). It keeps you in form and protects your joints.

    Also, keep a steady pace where your heart rate isn’t through the roof. You can “walk” on a bicycle just as well as you can sprint. Go far rather than go fast.

    1. And wear a helmet! Please!!

      I know three people who’ve had bicycling accidents that caused head impact; the two not wearing a helmet suffered significant brain injuries (fortunately, neither died). The other rammed (helmet-covered) head first into the windshield of the car that hit her, breaking the windshield and cracking her helmet, but she suffered no brain injury.

  14. Mark,

    You sweetheart. Thank you so much for answering my email about cycling. I truly appreciate it. I no longer am a slave to the weekly, insane 100+ mile rides like I was a few years ago and I do really appreciate all of the other healthy aspects about a good ride with good friends outdoors. I’ll keep your advise in mind if ever my ultra-endurance demon begins to poke me in my saddle again!

    Cheers to you,

  15. You say that the chronic cardio and the constant over taxing has the potential for making the heart walls thicken leading to AFib down the road. Is there any possibility of that happening if you are doing lots of interval type work?

  16. I had little to no morning sickness during my pregnancy. I think supplementing magnesium and keeping my blood sugar level were the keys.

  17. Mark, please clear up some confusion. The study that shows that butyrate improves insulin sensitivity and blood glucose control was done with the supplementation of butyrate, not resistant starch.

    Why don’t we just eat butter instead of resistant starch?

    From the study.
    “Dietary supplementation of butyrate can prevent and treat diet-induced insulin resistance in mouse. The mechanism of butyrate action is related to promotion of energy expenditure and induction of mitochondria function.”

    1. Other sources of butyrate.
      Next up, Nutrition Data (I believe butyric acid is noted as 4:00) Foods highest in 4:00 per 100-gram serving. Here is a selection out of the top 15:

      Rank Food Name
      1 Roast beef spread 4:00: 6399mg
      2 Butter oil, anhydrous 4:00: 3226mg
      3 Butter, salted 4:00: 3226mg
      8 Cheese, goat, hard type 4:00: 1784mg
      9 Cheese, parmesan, grated 4:00: 1510mg
      11 Cheese, goat, semisoft type 4:00: 1496mg
      13 Cheese, romano 4:00: 1355mg
      15 Cream, fluid, heavy whipping 4:00: 1200mg

    2. IT’s to do with where the butryic acid is formed. if you ingest it in butter, for example, it doesn’t make it to the colon,where it’s needed. However, when ingesting resistant starch the butryic acid forms in the large intestine.

    3. Well, resistant starch promotes butyrate production in the colon by bacteria. Butyrate in butter has some cool effects, but it doesn’t make it to the colon (whose cells function best on butyrate as an energy source, actually, which makes me think it’s an evolved, adaptive relationship between host colonic cells and colonic bacteria).

      Plus, it’s not an either/or situation. We can and should eat both to cover all our bases.

      1. And the question is for me, more upfront than most others because I’m a type one diabetic, if it’s called resistant starch, as opposed to indigestible starch, then that means it just resists digestion meaning that some of it is digested into glucose.
        Any thoughts on this would be appreciated

        1. From the studies we’ve seen, resistant starch doesn’t seem to raise blood glucose. The easiest way would be to eat a modest amount (teaspoon or so, however many “carbs” are usually enough to raise your glucose) and test your blood sugar.

          For what it’s worth, Steve Cooksey is a type 1 diabetic who did a 30-day experiment with resistant starch and found it to be a huge success:

          Good luck!

        2. Thank you Worker Bee. Steve is a Type 2. He makes his own insulin. I don’t. I have tried resistant starch, 2 tbls at. Bed time. It made both my blood sugar go up and then i have to inject extra insulin to bring it down.

          Blood sugar down is good as long as insulin is not up. Whatever is starch is not indigestible will turn to glucose. I can’t have that.

          Does anyone have info on the insulin spiking properties of RS? I have been looking.

        3. Hi Andre, I am a T1 diabetic as well, going on 25 years now. RS in the form of Bob’s Red Mill potato starch, taken 2-3T in the morning mixed in cold water, does not raise my sugar at all. In fact, it seems to improve my insulin sensitivity as well. SInce I follow a VLC diet a la Dr. Bernstein, and have been doing so for over 3 years now, I started with the RS a month or two ago to try to improve my gut flora situation (I think they had all been starved out … I was chronically constipated) since I don’t eat carbs other than those in non-starchy vegetables. I couldn’t believe it doesn’t raise my sugar AT ALL. People have been talking about it on the FB Diabetics for Dr Bernstein’s Diabetes Solution group. Worth a try IMO. Good luck!

        4. Thank you Laura I will give it a shot and try it in the morning instead of the evening. I would love to know your List of what has worked for you in the last three years Dr. Bernstein truly was the man who saved my life and turned my understanding in the right way.

          I currently work with Dr. Ron Rosedale and I’d love to converse with you. My email is [email protected]

  18. I’m pregnant with my third child and this is my first primal/perfect health diet pregnancy – and it is a completely different experience than last time. Significantly less fatigue, less morning sickness, much less weight gain, less aches and pains – I feel great and I only started showing recently at around 20 weeks. While I’ll never know for sure that it’s the diet (this is the last baby so no more experiments in primal pregnancies after this one), I like to joke that this baby is made out of egg yolks and butter!! Whatever it is, it’s working for me, so thank you Mark and Carrie!

  19. Coconut oil also has a host of benefits besides the MCTs. Dr. Mary Newport has an interesting story, Bulletproof Exec had an early podcast with her.

  20. The link to the article on A Fib takes you to a page that requires a password, so can’t read the article. Mark, would you elaborate more on changes in the heart from over training, and some parameters for what constitutes too much training? Is it the intensity that causes heart thickening over the long haul, or long duration? Would appreciate more info on how exercise affects the heart, after decades of being told that aerobics reverse heart disease and that sort of thing!

    1. I’d like more info on this as well. I’m training for my first tri and have been trying (ha!) to train in a specific target heart rate, around 150-160 (25 year old, female) per the advice of the training program I’m using; however, I have found it difficult to keep my heart rate in this zone while running, and can’t run more than a few minutes without my heart rate reaching 170. Should I really be more vigilant about keeping my heart rate down, from both a training pov and a heart health pov?

      1. I’m just gonna guess here. Mark would of mentioned it if Afib happened with HIIT and I’ve never read or heard of it happening with high intensity stuff.

      2. Many people (like me) find that more low-heart-rate runs make for better performance later. I had to slow down and walk-run to keep my heart rate under 140 on my initial runs. It was humbling. But I was able to go faster and do more eventually, and the runs felt invigorating rather than exhausting. I also did some sprints weekly to increase my speed. The <140 bpm runs were to "build the base" of my endurance fitness.

        I did an experiment & tried just doing runs in the 150-170 range for a month last fall, rather than keeping heart rate low. I felt terrible, got fatter, and did not get faster. That was following a program that just said you should aim for a certain speed and distance rather than keeping a low HR. Never again.

        Success for me involved about 3 run/walks a week staying between 120 and 140, and then a sprint session/week that sometimes hit 185, and maybe a short (2 mile?) run/week "for time" without paying too much attention to HR.

  21. So saturated fats and MUFA’s are not broken down into subcategories like omega3/6 like PUFA’s are? Are some saturated fats better than others, or is it all about the source ie. Grass Fed beef vs. Coconut oil? Just curious

  22. Thanks for answering my question, Mark. I did find some other info that hits on the answer to my question on Peter Attia’s site, in seeing his glucose response during his own experiments on himself. You guys are both great resources, I especially appreciate the ubiquitous links to studies and your sensible reactions to their conclusions. Thanks again.

  23. I had awful nausea/borderline hyperemesis gravidarum when I was pregnant. It was awful. I really could only stomach salty food and mushy comfort food most of the time. Think Lay’s potato chips and TV dinners. I wish my husband knew how to cook – I would’ve asked for kale chips and cauliflower casseroles instead.

  24. Great post Mark. Some very good points covered and the feedback to the comments is great too.



  25. Okay, Mark. This is the first time I’ve been here, and I have to say, great blog. Really, well researched, factual information. I’m new to a primal lifestyle / diet, and at the ripe ol’ age of 56, I think this is spot on what I need – just the facts. I’ll definitely be coming back for more.

  26. My question is still: Does resistant starch in the form of potato starch still have calories? I’ve seen competing information – from 2 calories per gram on Richard Nikoley’s blog to ‘don’t count them’ – at least as carbs – here.

  27. Interesting info concerning a-fib. I had “lone a-fib” attack at 53, converted to normal sinus in the ER after the usual meds. Discharged from overnight CCU observation with slight tricuspid murmer otherwise normal. Back then (I’m 59 now) I was eating ovo/lacto vegetarian, zero exercise, and about 50 lbs heavier than I am today, 2.5 months paleo, “running” 1 to 1.5 hours (usually more like trotting) on the beach sand or up and down hills + a few push-ups, dips, sit-ups etc. 2 or 3 times a week. I feel SO MUCH better now–especially my joints, sans carbs–plus lowered my blood pressure and pulse from borderline hypertension to teenage athelete numbers! Now MDA is saying the exercise might be bad for me? Huh. Even my MD wants me to continue my little “workouts.” Of course, she also advises me to eat whole grains and avoid red meat…

  28. That’s why I went off rooibos tea when I was pregnant with my third child. Couldn’t stomach it for years afterwards and now I like it again. It’s a herbal tea and could explain my reaction. I also went off tuna. Ugh. Now I love it. Wonder what caused the strange craving for tomato juice in my first pregnancy. I wouldn’t drink that now. Thanks for an interesting post.

  29. 5 weeks into my pregnancy my sense of smell went up 100-fold. I could smell things from miles away it seemed. I developed an aversion to meat and it was hard to eat anything in general. The pregnany left me permanently insulin resistant.

  30. Type II diabetic-no meds-diet controlled and have been using resistant starch for two months. I read everything possible to read about it and thought what the heck let’s give it a try and all I can say is WOW. Last week I had the lowest average reading (94ml/dl) since being diagnosed 3½ years ago. I live here in Portland, OR home of Bob’s Red Mill and can go to their store to buy their Potato Starch in bulk.

    I have begun experimenting with White Beans (canned Cannellini) making hummus. Perfect-no sugar spikes.
    White Rice cooked and cooled over night. Same thing. Perfect-no sugar spikes.
    If I were to eat either of these things hot I would spike somewhere over 200ml/dl

    Breakfast rice cereal recipe:
    ½ C rice 1 C water-cook
    rinse-cool over night
    morning: take ½ rice-put in a bowl, add ¼ C water, heavy cream to liking about ¼ + C, 2 drps liquid Sucralose (Yes I use lots of it) and a little cinnamon if wanted. I had this as a child and have always loved it. Of course back then it was with sugar.

    Don’t know why-don’t know how-all I know is it works.

  31. Just wanted to share this theory for why morning sickness exists:
    Basically, the self-induced “famine” causes the body to produce a larger, more efficient placenta which when grows big healthy babies once the self-induced famine is over. When I was a student midwife, I paid attention to placenta size and experience of morning sickness, and there did seem to be a strong correlation….the more sick, the heavier the placenta.

  32. I was eating primally for 2 months before I got pregnant this last time (and supplementing magnesium for over a year, so that didn’t help). About 6 weeks in, I started to experience the worst morning sickness/food aversions ever. I literally could only eat white things – potatoes, crackers, baked goods. I couldn’t stomach any fruits or veggies (not even cauliflower) except for tomato based salsa, lemons and lumes, and I couldn’t eat more than an ounce or two of protein without getting a stomach ache. The act of food preparation made me sick (I was cooking all of our meals before). I could only drink water, milk, and lemonade, where I was drinking alot of herbal tea before, but I was completely turned off of it. I also couldn’t handle anything mint or ginger – which is REALLY weird because usually those ease morning sickness. Most of the morning sickness is gone now (I’m 18 weeks), but still dealing with some food aversions – thank goodness protein and some veggies are back on the table now!! Women who don’t experience morning sickness are just plain ol’lucky, no other explanation available.

  33. I had terrible hyperemesis gravidarium with first child. Seven years later, 2 years primal, two years supplemental magnesium, adrenals in healthy working order and guess what…… exactly the same hyperemesis as I had with my first. I believe I am allergic to HCG and that is the main reason for this sickness for most women that have it past the first trimester. We produce the most of hcg in the first trimester and it slowly comes back down again in the second and third trimester. Which went along with when I felt the sickest always the first trimester and by the third it was substantially better. I couldn’t stomach anything but carbs cereal, toast, crackers no meat very little veg and no way could I stomach preantal vitamins. That was no way around this either, I am counting on the fact I was primal two years before this and extremely healthy!!! But to any women lookkig for the miracle cure trust me there isn’t one just be as healthy as possible before conception!!!

  34. Dealing with a pregnant wife now! She ate terrible before and it has only gotten worse lol. She can barely keep anything down. I started making her a fruit smoothie in the morning for calories (although it has a ton of sugar in it).

    What do you think? Half organic banana, cup full of frozen strawberries, 1 cup coconut milk and 1/2 cup water. I have to figure it is a 1000x better than the bowl of cheerios she was eating 3x a day lol

    1. Hi Evan,

      I am currently 12 weeks and am loving my Ninja for smoothies. Try adding some almond butter for healthy fats and protein. You can also hide a handful of spinach and she won’t even taste it! You’re a good hubby 🙂

      1. Great idea about the almond butter! I will throw in some next time. Not sure I’d get away with the spinach lol

  35. On that patellar cartilage deformation study:

    – agreed that % deformation correlates with force, however, cartilage only deforms to a certain point, which means that force can continue to act upon fully-compressed cartilage without the deformation percentage changing. This is why one can easily argue that running is still higher impact than cycling

    – within reasonable bounds it is a desirable thing to compress cartilage as the compression-release action is one of the few ways in which nutrients can be absorbed by the cartilage (remember cartilage has no direct blood supply, but is “fed” by the synovial fluid).

    My opinion (if it matters 😉 : a 45 minute to 1 hour bike ride, with the seat post set properly, and gears set to lower resistance, is still less total wear and tear on the patellar cartilage than a run of the same duration, particular if running on asphalt. The deformation may be similar but the blunt forces and sheer forces on the back of the kneecap are different (less) than that of running.

    As Mark has clearly stated (and I’m paraphrasing here): You can take almost any activity and turn it into chronic cardio with all the joint-destroying characteristics that go along with CC. Heck, through-hiking the Pacific Crest Trail in record setting time could be considered chronic cardio in my book.

    Good post Mark, Thanks.

    –Joe Miller
    Queenstown, MD

  36. About carbs and calories in resistant (potato) starch.

    As I record everything I eat, and with the assumption of 4 TBL’s a day of PS, it behooved me to find out what/how it gets digested.

    One of the first bags of Bob’s Red Mill PS listed the calories as fats! Yessirree. Later bags, standard carb 4kcal/gram.

    After lots of research, I’ve settled on 30kcal per TBLS as fats.

    Weirdly, consume PS and start measuring your serum glucose. While ordinary starch starts increasing BG in ten minutes, nothing with PS. But then at about 45 minutes, when standard starch is starting to peak, there is a bump with the PS! (I don’t remember how much.) But then it’s gone by 60 minutes.

    It definitely isn’t being digested as standard starch.