Dear Mark: First Trimester Frustration, Liver Dosage, and NY Times Barefoot Piece

Being pregnant is tough – or so I hear. You’re tasked with creating a child, with actually building an entire human being bit by bit from scratch. You have to carry that child, even as it grows to seven, eight, or even nine pounds or more inside your body. And all the while, your body seems to be rebelling against “what is best.” You want to eat the best food and get the right exercise and do all the right things, but what happens when your body fights you? What are you supposed to do when all you can stomach are mac and cheese and tortilla chips? For the first section, I try to help a woman in her first trimester with these issues. Next, I discuss the question of retinol overload from dietary liver, along with whether or not we need to worry about nutrient density in other organs, too. And finally, I give my take on a recent NY Times piece on barefoot running that seemed to call its usefulness and relevance into question.

Let’s go:


I am in my first trimester and have read several of your posts on pregnancy. However, I am seriously struggling to maintain my primal/paleo lifestyle. I can barely stand the sight or smell of meat. I have been able to eat some vegetables and fruit. I have been primal/paleo for a year and love it! It seems though that my pregnant self does not love it. I am so concerned that I am not feeding my body and baby the best food as I have been giving into eating whatever I can manage to keep down. Many foods that sound appealing are foods from my childhood…mac and cheese for instance and tortilla chips. I worry that going away from primal/paleo will make this pregnancy more difficult and is not healthy for my baby. I continue to CrossFit 3-5 times per week, but not having enough good fuel has made that more difficult also. Being so putt off from meat, nuts and many vegetables is making this extremely difficult and I am at a loss as to how to handle this.  I guess I am just concerned and would appreciate any words of advice you may have.


First of all, don’t stress out about this! While nutrition is important during pregnancy, so is stress management. And not just for the health of the future baby, but also for your health, including your ability to cope with postpartum depression. So, you know, take walks, get massages, try out meditation or yoga, get your partner to give you foot and back rubs – that sort of thing. Besides, the first trimester is notoriously hard on a woman’s appetite. Things should improve as time goes on.

Make super smoothies. Invest in a good blender. Toss in some frozen fruit, ice, some milk (if you do dairy), juice, or coconut milk, some protein powder, a few egg yolks, an ounce or two of nuts, and a handful or two of leafy greens. The egg yolks will provide choline, folate, vitamin A, and healthy fat. The fruit will give you phytochemicals and vitamins. The milk will provide protein, fat, and minerals. The coconut milk will provide medium chain triglycerides. The protein powder will give you protein. The greens will provide folate and minerals. The fruit flavor should predominate, making it easier to get down. You can even toss in some fish oil without it really affecting the taste much.

Get a good prenatal. Prenatals are there to give you what you need in the (likely) event that eating healthy food is impossible or repulsive. Chris Kresser recommends Pure Encapsulations Nutrient 950 with vitamin K2. Whatever you get, make sure it contains folate, rather than folic acid.

Primalize your non-Primal foods. Let’s take your two examples – mac and cheese and tortilla chips. If mac and cheese are all you can eat, dress it up. Buy gluten free mac and cheese (usually made from rice). When you make the cheese sauce, add a few egg yolks (from a farm you trust) to the mix; you won’t even know the difference. See if you can’t handle adding some ground beef or a few ounces of baked salmon to the mac and cheese, or maybe even some chopped, steamed spinach. Get tortilla chips cooked in lard or a high-oleic seed oil. Check the nutrition label for a high monounsaturated fat content and a low polyunsaturated fat content. Instead of just eating salsa, make a nutritious dip for the chips, like guacamole. Add an egg yolk to your guacamole (trust me, it tastes good, especially if you make it from scratch).

Reduce the CrossFitting. Five times a week is too much, in my opinion, especially if you’re doing full-fledged 20-30 minute WODs. Reduce the intensity, the duration, and the volume. Stick to 2-3 workouts a week, focus on strength versus metcons, and do a lot of walking.

Eat high quality cheese as a snack. Since you’re loving mac and cheese, real cheese shouldn’t be too much of a stretch. Cheese is high in protein, fat, calcium (important for the baby’s growth), conjugated linoleic acid (if it’s grass fed, especially), and even vitamin K2 (if it’s grass-fed and aged). Pecorino romano is a nice aged choice that’s almost always made from grass-fed sheep’s milk.

Check out Chris Kresser’s guest post from a while back and focus on the foods he outlined. You may not be able to get all the “sacred fertility foods” down, but at least you’ll have something to work toward.

Dear Mark,

Liver is awesome. But how much is too much of a good thing?

Do other organs (kidneys/hearts/lungs/brains) present the same problems with regards to retinol or other vitamins?


We’ve all heard the stories about the hungry Arctic explorers who died from retinoid overdose after eating polar bear (or sled dog) liver, and almost every pregnant woman has been admonished by her doctor to avoid liver because the vitamin A can increase the risk of severe birth defects. And yes, it’s true: you shouldn’t eat polar bear liver because of the extreme retinol content and vitamin A supplementation has been linked to birth defects.

That said, polar bear liver is special; just a gram of it contains between 24,000 and 35,000 IUs of retinol. A gram of beef liver contains just 165 IUs. Lesson? Don’t eat polar bear liver.

As to the risk of birth defects from liver, that’s been overblown. Retinol from food does not have the same effect on the fetus as supplemental retinol, and even though a 1995 study proved this, “avoid liver” is still standard advice given to pregnant women. In the study, women received retinol in the form of fried calf liver, oral supplements, or intramuscular injections. Both types of supplemental retinol caused huge spikes in all-trans-retinoic acid, the primary teratogenic (causing malformations to the fetus) metabolite of retinol, while liver caused no such spikes. Levels of the birth defect metabolite were 20-times higher than baseline after supplementation.

We’ve also heard that “vitamin A causes osteoporosis.” But that’s an oversimplification that ignores the very real phenomenon of nutrient interactions. Our bodies didn’t evolve eating isolated supplements. They evolved eating whole foods, and, as Chris Masterjohn has shown, it appears that vitamin A only really becomes a problem for our skeletal health in a vitamin D-deficient state. Of course, most experts won’t ever speak with that kind of nuance, instead preferring the easy way out of making declarative statements about isolated compounds.

None of the other organs you listed contain comparable levels of retinol, but they, along with liver, are rich sources of copper and iron – two essential minerals that we need but can also overdo. Folks with iron overload disease should limit their organ intake, or at least keep an eye on their levels.

I’d stick to around a half pound to a pound of liver per week, max. A bit more if you’re eating non-ruminant liver, which is lower in retinol. Less if you’re also eating other organs (not because of the retinol, but because of the copper and potentially the iron).

Good on you for eating organs!

Thought I’d show this to you. Thoughts? I’m a barefoot runner of 3 years. I can run 30km easy. I can’t run 1 km in shoes without pain. Obviously I’m on team barefoot.

Myths of Running: Forefoot, Barefoot and Otherwise


Ultimately, by defining the “best way to run” as that which allows the runner to “use the least energy and run the fastest,” I think they miss the main point of barefoot running: to reduce injury and prolong one’s ability to run and be active. Going barefoot isn’t really about being the fastest runner around. It’s about removing a barrier between the ground and your foot to heighten proprioceptive awareness and allow your body to make subconscious adjustments on the fly. Instead of having to consciously decide to adjust your gait to avoid injury, an experienced barefoot runner will do so more quickly and with less hesitation – since that barrier to awareness has been removed or reduced. And besides, there is evidence that running barefoot or minimalist improves running economy. Anyone who’s seen Barefoot Ted trotting along a trail can attest to this. And I’d assert that you when running barefoot you don’t have to run as far (or as fast) to get the intended strength and muscle development.

Although it’d be tough to put together a study that tested for this, I also think a big advantage to barefoot running is that it’s simply more enjoyable to experience the world that way. Our feet are remarkably attuned sensory organs, with nerve endings blanketing the bottoms of our feet, just begging to be used. Ram Dass once said “If you wear shoes, the whole world is covered in leather,” and I believe it. Feeling the grass between your toes, the sand beneath your feet, and yes, even the occasional sharp rock digging into your heel is an essential (but now missing) part of the human running (or walking) experience. You won’t find that aspect detailed in PubMed, but I think it’s pretty darn important all the same.

For some people, heel striking might be the fastest way to run and win races. I don’t care about that anymore, and I’ve never claimed that. All I know is that the heel strike is the improper way to land for the bare, natural human foot. So the fastest runners in the nation land on the heel, with the foot splayed out, with pigeon toes, and so on? Great. They’re fast in spite of their form. And the millions of people who read that article aren’t the fastest runners in the nation, nor are they getting paid to go out and run. They’re running to be healthier, and I worry that looking at what the professionals get away with is only going to open up the amateurs to injury and disappointment.

Thanks for reading, folks. Take care and Grok on!

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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 more than three decades 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 flavorful and delicious kitchen staples crafted with premium ingredients like avocado oil. With over 70 condiments, sauces, oils, and dressings in their lineup, Primal Kitchen makes it easy to prep mouthwatering meals that fit into your lifestyle.

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