Dear Mark: O6:O3 Ratio, Green Drinks, and Shin Splints

It’s Monday, and that means it’s time for another series of Dear Mark questions and answers. I think you’ll find today’s choices pretty interesting. First, I field a question from an apparently healthy reader who’s doing everything right, losing weight, and controlling the quality of his fat intake – but he can’t seem to avoid a 20:1 omega-6:omega-3 ratio. Next, I answer a question about green drinks, those vegan canisters of powdered, dehydrated, raw leafy vegetables that one mixes into juice or water for an instant daily dose of greens. They sounded silly, and I’ve dismissed them in the past, but as I did a bit more research my thinking began to change. Ideal? No. A fair compromise for some people? Maybe. Finally, I cover shin splints for a reader suffering from them, and I offer a bit of advice on how to avoid and treat the nasty things.

Let’s get it going.

Dear Mark,

I’ve been living primal for the past six months. I’ve lost 40 of the 80 pounds I wanted to lose and it hasn’t been hard at all. The only thing I’ve been having trouble with is the Omega 3:6 ratio. It doesn’t matter how precise I try to be with the fats I consume it always ends up being around 20:1. Help!

Thank you,


You wrote that your O3:O6 ratio is 20:1; did you mean to say “O6:O3 ratio”? Because that would make a huge difference. I’m going to assume the latter. I’m going to guess that you’re eating way more omega-6 than omega-3, because that’s a pretty common problem. If so, answer the following questions.

Are you still using crappy cooking oils? Check out this list of oils, review the PUFA content (most of which will be omega-6), and choose accordingly. Stick to olive oil, macadamia oil, butter, coconut oil, and ghee as you primary fats.

Are you eating lots of nuts? Newly Primal often go a bit wild with the nuts, because they’re delicious, they qualify as Primal, they make tempting snacks, they’re easy to overeat (being fingerfood and all), and they are calorically-dense. Many, if not most varieties are also significant sources of omega-6. Keep nuts to small servings, snacks, or as accompaniments to meals – not as whole meals themselves. Also, choose your nuts wisely. An ounce of almonds, for example (just 23 single almonds, contains over three grams of omega-6. An ounce of walnuts (14 halves) contains almost 11 grams of omega-6. An ounce of mac nuts (around 12 nuts) contains under one gram of omega-6. All that said, high O6 nuts can still be enjoyed, offer lots of other nutrients (many of which protect the fragile O6 fats from oxidation), and are certainly better sources of O6 than the aforementioned refined oils. Just be smart about it.

Are you eating lots of poultry and pork, rather than ruminants like lamb and beef? Poultry fat, although it’s delicious with roasted sweet potatoes or as crispy skin, has a good amount of omega-6. If you’re doing skin-on chicken thighs every night, you’ll be getting a big dose of omega-6 on a regular basis. Pork fat contains less omega-6 than poultry, but enough so that a pork heavy diet could leave you saturated with polyunsaturated fat. Plus, recent evidence suggests that some pork fat may be far higher in omega-6 than previously suspected (up to twice as much!). Beef and lamb, however, contain miniscule amounts of omega-6, with most of the fat being saturated and monounsaturated. Even conventionally-farmed beef and lamb have insignificant amounts (though it has far less omega-3 than grass-fed).

Are you taking fish oil or eating fatty fish? Do so.

Do a final run through on this handy guide to the omega-6 content of various foods and see what’s going on. I just linked to it yesterday, but it’s worth going over again (and even bookmarking).

However, if you truly are eating 20 times more omega-3 fats than you are eating omega-6 fats, it’s a good idea to ease up on all the fatty fish, flax, chia, and hemp. My sneaking suspicion is that you’re miscalculating something, somewhere. I’ve never come across someone who’s gone fully Primal and managed to maintain quite so lopsided an omega-6:omega-3 ratio (in either direction).

Dear Mark,

There are several “Green Drink” formulas on the market now – usually comprised of powdered dehydrated dark greens like spinach, kale, broccoli, etc. Do these confer the same benefits as eating the vegetables, and are they readily absorbable by our bodies?

LOVE what you’re doing here, and thank you kindly in advance!


Normally, humans have trouble extracting massive amounts of nutrition from raw greens like spinach, kale, and broccoli. We might enjoy the crunch they provide, the texture, and even the taste, but the simple fact is that we are not equipped with the necessary cellulase – a digestive enzyme – to fully breakdown the cellulose that makes up around a third of said raw leafy vegetables’ cellular structure. Without breaking down cellulose, we can’t access all the vitamins and nutrients located therein. The impressive stomachs of certain animals, like cows and sheep and gorillas, contain billions of symbiotic microorganisms that make cellulase so the animal can derive the bulk of their nutrition from fibrous plants, but ours do not.

That’s why we cook, chew, blend, liquefy, ferment, sprout, and process our food. So that we can bypass our physiological limitations and access the nutrients. What about green drinks?

As you point out, green drinks consist of powdered, dehydrated vegetable matter. Dehydrating and then turning into powder leafy greens should, in theory, break down enough cellulose to make the nutrients bioavailable to humans, similar to the idea behind consuming vegetable smoothies. There’s some evidence that blending fruit and vegetables into smoothies makes them more bioavailable, though the quality of research varies:

  • In one, apple smoothies resulted in greater absorption of apple polyphenols, but the controls were poor – two others groups who either consumed cloudy apple juice or apple cider. I would have liked to have seen a group that simply ate whole apples.
  • Another review paper (PDF) found that, by and large, increasing the surface area of a food (by juicing, chopping, blending, or pureeing) increases the bioavailability of the nutrients in that food. In other words, the more pieces and the smaller those pieces, the greater the nutrient accessibility.

Since powdered vegetation has far more exposed surface area than even well-chewed whole vegetation, I think the nutrients should be plenty bioavailable – assuming dehydration preserves nutrients. Does it?

I’m definitely a fan of just eating the whole fruit or vegetable over a powder, but it seems like green drinks can be a helpful tool. If you’re interested, I’d suggest you try one out for a few weeks and see how you feel. Oh, and since we also know that fat improves absorption of many nutrients (it’s why I always cook my spinach in butter), be sure to mix it with coconut milk or add a couple egg yolks. I’d also seek out products that use gentle dehydration techniques, preferably freeze drying. A lot of the “raw vegan” green drink mixes should be gently dehydrated.

I would love to see an article covering shinsplints (and possibly other common running injuries?).

I’m not a new runner. I’ve run on and off for about 9 years. I wasn’t running much earlier this year and started over the summer – only to quickly get shinsplints, which I had never had before. At one point it was so tender to touch I could hardly stand to do power cleans. All of the information I’ve found is very traditional and does not address potential gait or shoe problems. The recommended therapy is ice and rest – which I’ve done with little improvement. This has been especially disappointing because I’ve already seen improvement just doing the Crossfit Endurance WODs (even though I have rowed most of them). I’ve found very little information about this problem out of the paleo/primal crowd so I thought it wouldn’t hurt to submit a question.


Ah, yes, the shin splint – every runner’s arch-nemesis. When I used to compete, we just assumed and accepted that shin splints were an inevitability. Pain was normal. Man, does that sound insane (and defeatist) now that I think about it.

First and foremost, analyze your gait. Are you a heel striker? Don’t be. Land on the midfoot to forefoot when you run. Wearing minimalist shoes or going barefoot will help with this and make the landing more natural and intuitive; wearing bulky running shoes with a prominent heel will make it more difficult.

Second, be wary of overstriding. I see a lot of runners (usually heel-strikers, but not necessarily) reach out with their feet as they land, taking huge strides and never quite allowing their bodies to catch up with their landing. Rather than land with their feet directly underneath their hips, they land with their hips trailing their feet. Instead of flowing along across the landscape like a gazelle, they’re plodding along in fits and starts, momentarily slamming on the breaks with every over stride. This is extremely stressful. Take shorter strides, land softly.

Third, don’t go too far too quickly. Moderate your running. Listen to the warning signs your body is putting out. If you’re hurting, stop. If you’re starting to get tight in the lower legs, slow down. The shin splint is merely your body throwing up its hands in frustration at being ignored for so long.

Fourth, don’t push off with your toes. You’re not jumping or bounding. You shouldn’t be doing a bunch of mini calf raises. You’re engaging in controlled falling. Move at the hips.

If you’re a fan of Crossfit Endurance, look into Pose running. That’s the method Crossfit Endurance creator Brian MacKenzie teaches, and it should help your form and pain issues.

As expected, the illustrious KStarr has a helpful hack for fixing shin splints. Go watch the six minute video and try his fixes. I’ve yet to be let down by his stuff (part of the reason why he’s coming to PrimalCon next year!).

I also came across an interesting set of drills designed to strengthen your calves for eccentric loading (which, during the course of running, your calves have to deal with after every stride). Try ’em out; they’re pretty simple and can be done without any fancy equipment.

Got questions? Perfect, because I have answers. Send yours in and I’ll send mine out. Thanks for reading!

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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