Dear Mark: Pregnant Exercise, Low-Carb and Alcohol Tolerance, Ancestral Sun Dosages, and Knee Mobility

Today is Monday, which heralds another edition of Dear Mark. This week, I’m giving my two cents on what could be causing the widespread incidence of lowered alcohol tolerance in Primal eaters. It’s nice to be a cheap date, but sometimes we want to keep up with everyone else, right? I give a few ideas on exercises for pregnant women who want to remain active without any complications arising, and I discuss whether the amount of sun our ancestral homelands saw play a role in how much sun we should get. Finally, I discuss whether a knee should be mobile or stable, along with a few strategies to have and maintain healthy knees.

Let’s go.

Dear Mark,

I’ve been following your (awesome!) PB Fitness protocol for over a year now. I’m not pregnant at the time but I might be in the future, and I’m starting to wonder how to get on with my Four Essential Movements with a big belly in front of me. Some movements may be no probs, but how about doing pushups if the belly touches the ground right from ‘up’ position? And deep squatting, I’ve got this awkward feeling it might make you accidentally pee yourself due to all the extra pressure on the bladder… So, long story short: How do I subsitute the Five Essential Movements workout to make it suitable for pregnancy?

Thank you so much for all your work and a great webstie!


Let’s go through each of the movements.

Though I’ve never carried a child in my (nonexistent) womb, I think squats should be okay. I mean, have you seen elite powerlifters? They’re big dudes, some with big bellies (mostly muscle, though), and they have no problem squatting. Besides, squatting is a legitimate birthing position. If you’re worried about peeing yourself, there’s an easy fix: avoid exercising with a full bladder. You’ll want to squat with a fairly wide stance, wide enough to give your belly enough room to pass. Too narrow a stance and you might hit your femurs with your belly (again, see powerlifters, who tend to squat with a super wide stance).

Alternatives include lunges and Bulgarian split squats (featured in this WOW).

Do normal pushups until your belly starts cheating for you. Then, switch to feet elevated pushups. As long as you’re maintaining the rigid plank position through the legs, hips, and torso, elevating your feet will also elevate your belly. Once your belly starts cheating on the feet elevated pushups, move to feet and hands elevated pushups. Parallel (dip) bars work well for these, as do a pair of sturdy, dependable chairs. The key is allowing your belly to move freely through space.

Alternatives include the bench press and the floor press.

Pullups are obviously fine. Just avoid doing pullups on flimsy bars. Enjoy the added resistance!

Be very careful going upside down for handstand pushups. If you’re not comfortable with these, go for the inverted V pushups: keep your feet and hands on the ground and stick your butt in the air to form an upside down V with your body; get your torso as vertical as possible and press using your shoulders as the prime movers. (And, by the way, if I were forced to choose 4 Essential Movements this would be the odd man out.)

If “elbows down” planks makes you belly-cheat, go with “hands down” planks. Fully extend your elbows and place your hands on the floor, as if you were in the top position of a pushup. Hold it. It’s not as tough as the elbow plank, but given the circumstances, that’s okay. Plus, you’ve got added central mass to support, which makes it hard in its own right.

I actually think PBF is perfect for pregnant women, because it’s bodyweight-based, very simple, and scalable to all levels of fitness. Of course, if you did want to increase intensity or handle big weights, you probably still could. Want proof? A fantastic blog – One Fit Mom – actually chronicles the pregnancy of a diehard Crossfitter who, rather than taking it easy, kept up with her workouts. She didn’t exactly break her PRs, but she stayed active and maintained her fitness and most of her strength. She gives lots of recommendations for exercise substitutions. And yes, she kept squatting and deadlifting.

Hi Mark,

I have been wondering about maintaining the Primal Blueprint diet and becoming more sensitive to wine and caffeine. Is there a physiological reason for this observation? Is it because less carb is consumed thus level of tolerance is lowered (considering how much carb can absorb wine/caffeine…)

Thanks for your input!


Interesting question, Angela (and thanks for the thanks). It’s not a new one. We get a lot of reports about Primal eating reducing alcohol tolerance, and while I don’t have a definite answer, I do have a rough inkling as to why alcohol tolerance worsens.

You mention eating fewer carbs – a normal, expected change for most people who adopt Primal eating. The carbs you’re no longer eating weren’t actually soaking up the alcohol; even though I knew guys in college who swore by swallowing hunks of white bread whole to absorb booze and prevent a hangover, it’s the simple presence of food in your stomach that slows the absorption of alcohol, not just carbs in particular. My guess is that breaking down and detoxifying the ethanol you’re imbibing is hard work for a liver that’s already tasked with the creation of glucose from amino acids in a low dietary glucose state (gluconeogenesis). We know that alcohol consumption inhibits gluconeogenesis by decreasing the availability of the “intrahepatic gluconeogenic precursors” by 61%. If alcohol detox and gluconeogenesis are competing for the same raw materials along similar pathways, and if the effects of alcohol increase with inefficient detoxification, it follows that someone drinking alcohol in a gluconeogenic state may be more sensitive to its effects.

If your tolerance to alcohol has become unpleasantly low with a correspondingly low carb intake, a simple fix may be to eat a couple sweet potatoes on days that you’ll be drinking. I don’t have the issue, and I stay around 100-150 grams per day, so I don’t think it takes a huge amount. Anyone else with lowered alcohol tolerance on the Primal Blueprint eating plan?

Hi Mark,

I’ve enjoyed your books and website. I just wanted to quickly comment on the sunlight issue.

Your blog posts discuss how we’ve evolved with sun exposure, and shouldn’t fear it, but don’t seem to remind readers that location matters.

For example I’m a red head, Caucasian of Irish descent, but I live in north Queensland, Australia. Hunter gathers native to this part of the world were black. I’m white and freckled. The amount of sunlight I should expose myself to here is surely a lot less than if I lived in a similar environment to my direct ancestors.

I’m not sure if some of your readers may overlook this if they are also living away from evolutionary roots.



This is a good point, Mike. Not everyone has the same level of innate sun tolerance, and I think ancestry is the major determinant. Sure, lifestyle factors in big time – what you eat (and, perhaps more importantly, what you don’t eat) famously affects your skin’s susceptibility to sun damage – but as for genetic sun tolerance? Where your ancestors grew up and how much sun they were exposed to on a regular basis probably determines how much sun you can tolerate, as a baseline. So for you, a red-headed Irish guy with freckles, a full hour in the midday Australian sun is excessive and probably even harmful.

Although I may not have recommended that readers pay attention to their ancestry when considering sun dosages, I have always maintained that people should avoid burning. My thinking is that as long as you avoid burning (or even developing a nice pink color), sun bathing is beneficial. This usually boils down to getting out of the sun as soon as it starts to feel uncomfortably hot, and I think it naturally dovetails with the ancestry idea. Just as the person with pale skin whose ancestors hailed from foggy climates can safely assume he will tolerate far less UV exposure than the person with dark skin whose ancestors lived on the equator, that same person with the pale skin/ancestors will feel uncomfortably hot sooner and get out of the sun earlier. It’s an important point that deserves explicit mention. Thanks for bringing it to my attention.

Dear Mark,

I’ve been working through some of the mobility exercises you’ve posted and I was just wondering if you could suggest anything specific regarding the knee. You’ve done posts on feet, ankle, hip, wrist, spine, and shoulder– is there any chance for a knee post in the future? I’m hoping you might have some Primal pointers, especially considering your recovery from your Ultimate mishap. Thanks in advance!


Well, my knee injury was an acute one, a freak accident caused by impact with the ground. It wasn’t exactly a mobility issue (although I suppose that could have played an indirect role somehow, maybe by impeding proper movement and landing). That said, this is a great question that deserves a response.

With the knee, we actually want stability – not mobility. Consider that as you go along the kinetic chain of the body and examine the joints that comprise it, their primary functions alternate. First is the thoracic spine (which needs mobility), then the lumbar spine (stability), then the hip (mobility), then the knee (stability), then the ankle (mobility). This is also true starting at the shoulder (mobility and stability), followed by the elbow (stability), and then the wrist (mobility). See how that works?

So in fact we want a stable knee, rather than a mobile one. A stable knee doesn’t bow inward when walking or squatting. It doesn’t collapse on you or buckle beneath you. A good, stable knee is a hinge joint. It definitely shouldn’t be rotating and bending every which way. That’s pathological mobility.

To protect your knee, then, you must maintain good mobility in the other areas, especially those immediately above (hip) and below (ankle). If you lose mobility in the hip or ankle, your knee must compensate for the missing movement. Your knee becomes mobile to make up for the missing mobility above and below, and since the knee isn’t supposed to be mobile, you get pain, and injury, and downtime, and co-pays, and surgery bills. All those hip mobility drills, and the ankle mobility exercises – that’s what you want. Those are the keys to healthy knees.

Bone up on the mobility series (which you’ve already been doing). They’re a good introduction into the world of mobility.

Foam roll your calves, quads, glutes, IT band, hamstrings, and basically everything in and around your hips, knees, and lower body in general. If your knees are hurting, you’re probably tight all over. If the foam roller isn’t getting the job done, graduate to a lacrosse ball.

Familiarize yourself with MobilityWOD. Run a search for “knee” and “hip” and “ankle” and “calf” and pretty much every body part. It’s not the most organized, but everything is good and worth watching. Consider picking up some of the stretch bands they use.

Even if your knees feel great now, by ignoring mobility issues up and downstream, you could be setting yourself up for disappointment – and injury – in the future. Take an active role in the health and movement of your tissues before it’s too late.

That’s it for this week. I have a decent queue of questions built up that I’m trying to get through, but I’m always accepting more – so send ’em along! Thanks for reading and leave your thoughts in the comment section.

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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