Dear Mark: Grok’s Mobility, Too Much Walking, Fertile Eggs, and the Best Shoes for Babies

Walking, Walking, WalkingHey folks, it’s time for another edition of Dear Mark. This time around we’ve got a four-parter. First up, I discuss why Grok probably didn’t need to foam roll with boulders or consult with a proto-Kstarr sporting a prominent brow ridge. Next, walking. It’s good, it’s vital, it’s low-stress, but is it possible to walk too much? Yes (but read on). After that, I delve into the extensive fertile egg literature. Er, maybe “extensive” isn’t quite accurate. Let’s go with “nearly non-existent.” And finally, I give the Primal pick for the best shoes for kids.

Let’s go:

Hi Mark,

Did Grok have to work on Mobility and listen to KStarr?

I’m 45 year old male who loves to lift heavy stuff (crossfit, strongman, oly lifting etc). I have not perfected my Grok lifestyle by any means but I was laying on the mats in my garage gym the other day, working mobility to prep for a workout, and thought to myself, did Grok have to do this? I mean I would be lost without working on mobility….

Was Grok always sore? Did he have to roll on lacrosse ball sized rocks to get ready for the days activity?

Thoughts/feedback as I wonder if it ever gets better?



Ha! Great question. Hilarious imagery.

I picked the brain of my buddy Angelo dela Cruz, of PrimalCon and VitaMoves fame, for his perspective and advice. In addition to being a great massage therapist, body worker, movement coach, and personal trainer, Angelo is one of those dudes who’s just “always on.” At the drop of a hat and without any real warmup, he’ll do a backflip, deadlift twice his bodyweight, or scale a building – because he’s always peppering his day with movement to stay limber. Anyway, here’s what he had to say:

We’ve created the need for mobility work, just as we have created the need for learning how to run barefoot or sit, stand, or walk with good posture. For most of us, our modern lifestyles don’t engage our muscles, connective tissue, & joints to a diverse set of movements that encourage a great level of mobility (or movement capability).

Chronic tightness and decreased ranges of motion could be regarded as deficits of the body. Whatever has happened to your body up to now has contributed to a “negative balance” in your mobility account. You can imagine mobility work as a type of investment. The more things you do that make your body feel tight on a consistent basis (activities, nutrition, emotional states), the more mobility work that your body may require to balance out or “get in the black”.

Will you always need to foam roll and do mobility work? You can think of that question to be similar to “Will I always need to brush and floss my teeth?”

As long as you’re alive and want good hygiene on the inside, movement will always play an important role in a human’s ability to enjoy life. However, if you don’t like foam rolling, I’d suggest finding more enjoyable ways to gain mobility and ways that you can get more bang for your buck. For me, that means breaking up the monotony of regular life with regular, easy, yet deliberate movement, or VitaMoves. I’ll start the day with a minute or two. Anytime I start feeling “stiff,” or realize I haven’t done anything in awhile or have been sitting for too long, I’ll get up and move. Most times, I devote a minute or two, so it doesn’t feel like work, but as a result I’m always ready to work out, lift, run, jump, or play without much warming up.

Like Angelo’s, Grok’s mobility account was in very good standing. A lifetime of good credit. Yours may not be, because you can’t (and haven’t been able to) spend your entire day moving around like a hunter-gatherer, rarely sitting (and never sitting in a chair with a keyboard in front of you), and your most comfortable position of repose being a full squat. You also exercise differently than Grok, who rarely engaged in repetitive motions for reps and sets. Ancient hunter-gatherers weren’t really setting aside 45 minutes out of the day to cram in 3×5 deadlifts or Tabata clean and jerks. Even if you use perfect technique, your tissues need more recovery after tons of reps simply because of the repetitive stress being applied to them.

All that said, informal systems of movement therapy have likely always been around. Early humans had the same brains as we do. They touched each other, they gave back rubs to loved ones, they figured out that having your thighs rubbed after a tough hunt helped recovery the next day and felt really good. Neanderthals were treating bone fractures and wounds and amputating limbs at least 130000 years ago, and it’s likely other early humans had at least rudimentary systems of medicine and “physical therapy.” They certainly used medicinal herbs. It’s not as if we just gave up and died en masse at the slightest hint of an injury or illness before modern medicine arose.

For the most part, though, I think formal mobility work is the product of and a reaction to a society that promotes and enables poor movement. It’s also kind of necessary if you’re going to work eight hours a day and then go to the gym. It can be annoying, but five minutes a day of movement work is way easier than dealing with a torn meniscus.

Is there such a thing as too much walking? After reading your article about not burning more than 4,000 calories per week through exercise, I’m starting to wonder. I bought a Fitbit in December and started walking A LOT. I’m averaging around 60 miles per week of walking. According to Fitbit, I’m burning about 26,000 calories per week. A sedentary person of my age/height/weight/sex burns 19,000 calories a week, giving me a differential of 7,000 per week. I’ve also noticed I’ve been losing muscle mass the last five months according to my Fitbit Aria scale. Thanks!


Yeah, there’s such a thing as too much of anything, I’d say. 60 miles a week is almost ten miles a day. Even if walking is “easy slow movement,” you’re still burning a lot of calories. 7000? Maybe, those devices aren’t super precise. It’s a good general barometer, though. Plus, if you’re walking upwards of 7, 8 miles each day, you’re sitting at a chronic daily calorie deficit. Calorie deficits work better in a fractal pattern, with a couple days of deficits followed by a day of maintenance or even surplus. That’s the basis for my recommendation of an occasional hypercaloric carb refeed; it helps restore lagging leptin levels and can increase metabolism.

The lost muscle mass is a definite red flag signaling that something needs changing.

Are you doing any strength training? Even on a caloric deficit, strength training is essential for maintaining lean mass. You’re not going to gain much of anything, but by lifting heavy things you’ll be sending the message to your body that you “need the guns” and they will be spared. If you’re not using them, they’ll get discarded because, well, you obviously don’t need all these stored amino acids that your liver would be happy to convert into glucose. Plenty of studies show that resistance training on a caloric deficit will retain lean mass, particularly with sufficient protein in the diet.

Cut the walking by nearly half and throw in a couple days of strength training. Bodyweight, barbells, machines, whatever. Just start stressing those muscles so they stop disappearing. You might eat more, and that’s normal because resistance training tends to increase appetite. You probably won’t lose weight as quickly, but only because you’ll be maintaining or increasing muscle. Body fat will drop, which is what you want.

Good luck.

Is there any advantage to buying fertile eggs? My health food store just started carrying them, and I wonder if I should indulge, or skip and stay with my pastured eggs?


Raw fertile eggs were one of the classic bodybuilding foods, along with raw milk and beef liver. Those last two have been vindicated by science – raw milk is obviously great for muscle growth, but it’s also rich with beneficial fat (if grass-fed, particularly), fat soluble vitamins, and helpful immunological components; liver is dense with practically every important nutrient, including vitamin A and cholesterol, which we need for testosterone production – but what about fertile eggs? Bodybuilding legend Vince Gironda said that eating 36 fertile eggs a day was comparable to using Dianabol (a steroid). There may be something to it.

Several online sources claim that fertile eggs contain a myostatin inhibitor called follistatin. Yeah, it’s a page on a supplement site hawking fertile egg extract, but the cited studies seem to confirm that fertile eggs (in sufficient amounts) can downregulate myostatin. Myostatin slows down muscle growth, so when you inhibit myostatin, you increase muscle growth. Animals with genetic myostatin deficiencies are ridiculously proportioned slabs of pure muscle, like the double-muscled cattle or the bulley whippet.

I’d stick with the pastured eggs, personally, unless your main focus is muscle gain. Might be a fun experiment to try. A dozen fertile eggs a day coupled with intense strength training? Anyone up for it? Anyone already try it?

Mark! MARK! I request, nay, demand a list of minimalist shoes for children! My five month-old will be learning to walk soon, and you can bet he’ll be in the softest shoes I can find.


Perfect timing for this one. We’ve got a couple workers around the office with either babies or incoming babies who are neck deep in this topic.

Vibram makes Fivefingers for toddlers and older kids (good luck getting a baby’s wriggling toes into a pair of those!).

Vivo Barefoot has a kids section, though I think it’s just for older kids and not babies.

And a UK retailer called Happy Little Soles sells only acceptably minimalist footwear for babies and kids. They’re all about “developing feet,” so you can use their product list to research other companies.

But the consensus choice around here is Bobux, a company out of New Zealand making soft, supple leather shoes for babies, toddlers, and other categories of youngster. In their “About” section, they explain how their goal was to “allow the feet to function properly and grow without restrictions.” That sounds extremely promising. The shoes are super flexible – you can practically roll it up and stick it in your shirt pocket if you’re so inclined – and they’re very light with a lot of ground feel.

Just in case anyone is on the fence with their kids and barefooting/minimalist shoe-wearing: a kid’s foot doesn’t stop maturing until around age 18. Particularly in the first several years, there’s a significant amount of cartilage rather than bone. Cartilage that’s “finding its way.” Cartilage that will take whatever shape (within reason; you couldn’t give your kid a three-toed chicken foot or anything) you impress on it. Cartilage that turns to bone. Plus, kids are establishing neural connections between their feet and brain using the sensory feedback they get from the ground, connections they’ll use as a foundation for their movement, balance, coordination, and athleticism for the rest of their lives. Putting them in thick, hard shoes removes that. Heck, even the American Academy of Pediatrics recommends a soft-soled, flexible shoe for the first year (though I’d say the first four to five years at least).

That’s it for today. Thanks for reading, everyone!

TAGS:  dear mark, Grok

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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