Dear Mark: Hiking and Body Composition, Hiding Liver, Unconventional Testosterone Boosters, Cooked/Cooled/Reheated Potatoes, and Sirtuins

Group of hikers walking in mountainsFor today’s edition of Dear Mark, I’m answering five questions from readers. First up, why isn’t hiking giving one reader the shifts in body comp they expected? Two, is there actually a way to mask the flavor of liver? Then I discuss a few unconventional testosterone boosters, followed by a brief treatment of the cooked, then cooled, then reheated potato. And finally, are there any dietary activators of sirtuin proteins?

Let’s go:

I’d like to see an article on the benefits of walking/hiking daily. I live in Colorado and average about 25 miles a week of walking. I know that it’s doing good things for my mind and body, but I don’t see any noticeable changes in my physique. Is there anything I can do to up the toning factor of my walks, besides seeking out hills? Thanks!

This is a hard one to grasp for people, especially since we talk so much about the benefits of walking, but I think it’s crucial.

Don’t think of hiking or walking as exercise. Just don’t. Not because it isn’t good exercise—it is—but because that mindset subtly alters how we act.

When something is “exercise,” it requires a reward. Our subconscious response to anything difficult is a hedonic reward, a “treat.” We “earned it,” after all. This works without you even knowing it’s happening. That’s why, in my experience, hikers are the biggest consumers of junk food around. I’m struck by the amount of snacking that goes on. Folks are always pausing on the trail to dig through their backpacks for trail mix, dried apricots, granola bars, and the like. You’re probably not doing this consciously, if you’re doing it.

When we treat hiking like “exercise,” it bleeds into our real training. “Oh, I hiked yesterday. I’ll skip CrossFit today.” No. Hiking and walking days are active rest days. Unless you’re climbing hills for six miles, you shouldn’t treat them like a hard session demanding post-haste refueling and carb loading.

Beginners to hiking and walking will find a few miles incredibly taxing. For them, it is exercise. But then you adapt, and it becomes easy and relaxing. That’s where I suspect you are. Twenty-five miles a week is excellent activity, but it’s a breeze.

I’d like to see more recipes that hide the taste of liver. I’m not a fan of the taste, but i’d really like to find ways to incorporate it into my diet.

At some point, you’re gonna taste some liver. It’s unavoidable.

Don’t overcook it. Overcooking liver heightens its bad qualities and depresses its good ones. When you overcook liver, you destroy all the sweetness—the glycogen—that makes good liver so good (or at least tolerable). When you overcook liver, it becomes a crumbly, chalky, bitter mess. Leave it pink inside.

Eat it as fresh as possible. Liver is repository of sweet glycogen, but glycogen is fleeting. The longer liver sits, the more glycogen depletes. If you’re thawing your liver, eat it soon after.

Frozen liver thaws quicker than you think. Most of my liver comes frozen—it’s fresher than the “fresh” I can get—and I’ll just start preparing it when it’s half-thawed. Easier to slice clean that way.

Try chicken liver. Chicken liver is far milder than ruminant livers. Plus, chicken liver is actually higher in iron and folate than ruminant livers. It’s also lower in vitamin A, so you can arguably eat it more often than beef or lamb.

Make raw liver smoothies. I find a few ounces of incredibly fresh liver in some fresh squeezed orange juice to be not just tolerable, but downright tasty. Try it. You’ll be surprised. And the liver makes the acute dosing of fructose worth it.

I have heard that the two best exercises for increasing testosterone in men are chopping wood and soccer. Is there any evidence or truth behind this claim? If so, why? The two activities do not seem very similar.

Both increase testosterone, yes. They’ve actually pitted the two against each other, finding that chopping firewood is a bigger booster than playing soccer among the Tsimane horticulturalists of Bolivia. Wood choppers saw testosterone rise by an average of 46.8%, irrespective of age.

The key distinction seems to be that chopping wood is an essential life skill. It’s the kind of “exercise” that serves a vital purpose: providing warmth, warding off predators, and allowing us to cook. The meaning comes baked in.

Depending on where you grow up, soccer might be an essential life skill, too. Even people watching their national soccer team play and win experience an increase in testosterone (and cortisol, because it’s so nerve-wracking).

Hunting does it, too. One study tested the testosterone of Tsimane hunters after a successful hunt. Ranging in age from 18 to 82 (yes, 82), the successful hunters all experienced significant increases in testosterone levels independent of age.

My favorite unconventional way to increase testosterone is solar irradiation of the scrotum. I swear I read this in an old journal years ago but can no longer find the reference. Can anyone help? It’s plausible, seeing as how taking vitamin D to correct a deficiency can increase testosterone levels. There’s no better way to get vitamin D to your testes than with the application of direct sunlight.

I know this topic has been discussed plenty. But just a quick question on “cooked and cooled potatoes”. Can these cooked and cooled potatoes then be reheated? Does it negate any benefits? I do not enjoy cold mashed potatoes but I do enjoy pan frying left over potatoes in coconut oil. Some clarification would be wonderful.

Yes. You can reheat cooked and cooled potatoes without negating the resistant starch. You may even increase it further, if what happens to cooked and cooled and reheated bread and pasta happens to potatoes.

Would love to know more about interaction of diet and sirtuins!

There are seven types of sirtuins, and most of them seem to be involved in protection against oxidative stress and aging or the maintenance of fat and glucose metabolism. Older people tend to have higher levels of sirtuin 1 to compensate for the higher levels of oxidative stress they endure, for example. In non-mammals, activating sirtuin 1 increases lifespan. In mammals, it’s sirtuin 6. Generally, sirtuins are “good.”

Dietarily, the two most reliable ways to activate sirtuin are reducing calories and eating phytonutrients like resveratrol (wine) or curcumin (turmeric).

Since things that increase sirtuin expression, like exercise, eating less, and eating colorful fruits and veggies and spices are already known to be healthy, I feel comfortable recommending that you increase sirtuin expression.

That’s it for this week, folks. Take care and be sure to chime in down below with your own input!


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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65 thoughts on “Dear Mark: Hiking and Body Composition, Hiding Liver, Unconventional Testosterone Boosters, Cooked/Cooled/Reheated Potatoes, and Sirtuins”

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  1. Well, sunbathing my testicles sounds quite pleasurable. Just seems pretty cumbersome – things need lifting or put “aside”, shaving, not to mention the positioning of legs.
    You said to “chime in down below” after all.

    1. Thanks for pulling this out of the archives. I haven’t seen it yet and I’m always looking for different ways to eat liver

      1. How I hide liver:
        A) I save up the liver (and hearts) that comes inside chickens and freeze it. When I get enough, I defrost and puree it, then freeze it in cubes (Wilton 24 cavity silicone baking trays). Then, when I make anything with ground meat, I throw in a few cubes.
        B) When I have a venison liver and/or heart, and venison scraps, I puree the offal, then put it all in a crockpot with onions and lots of curry powder. That comes out as a good breakfast meat hash, and you’ll never taste the liver. If it needs something else, mayo works.
        C) There are many good beef and chicken liver pate recipes out there. Paleomom has one, but just google and see what flavors you like. When it’s mixed up, taste it. If it’s too livery double up on the herbs and spices (and maybe the salt), and soon you’ll be rushing to the fridge all day for it. Great on cukes!

      2. and then there’s liverwurst. Venison liverwurst, with pork belly added is fabulous. But you can buy liverwurst, of course.

    2. Thank- you too – I hadn’t seen this one. Sounds delicious and I’ll try it this week.

  2. Quite an interesting mix for a Monday morning – from snacking hikers to solar irradiation of the scrotum! Love it!

    I’m glad you brought up the “I exercised so I get to snack more” pattern. I often see people frustrated that they’re walking or jogging daily with no change in weight or body composition. Constant snacking (and food choices) are often part of the picture.

  3. I’ve tried every recipe I can find to hide the taste of liver, all to no avail. I can’t stand the stuff.

    But discovered that most of the awful taste actually comes from cooking it. Raw liver, though not yummy by any means, is not nearly as obnoxious.

    So my solution to eating liver: I buy grass-fed beef or lamb liver, freeze it (usually for weeks), then chop it up very finely and re-freeze in ice cube trays. Each cube is about an ounce. In the morning (usually while waiting for the coffee to brew) I plop a liver cube into a glass of hot water to thaw it, add a dash of salt, then chug it down without ever stopping to taste it.

    Another thing: to me, lamb liver is much milder, even in the raw form, than beef liver.

    1. I’ve done something similar with liver. I take the small, unthawing chunks of liver, soak it in some lemon juice and then down it with a ton of hot sauce. The only thing I taste is hot sauce.

    2. I have done this too. I don’t even bother with the hot water…I just let it sit out for a few minutes and when it’s partially thawed I swallow it. The prep of cutting up all the little pieces of liver is a drag, but once that’s done it’s not too bad!

    3. John, this may sound as noting special but frying lots of chopped onions until they caramelize, add the liver, sprinkle with coarse Atlantic salt and fresh Black pepper and cook for about 5-10 minutes while mixing until the livers are crusty on the outside and pink on the inside. Chicken liver outshines beef liver as Mark said and goose is even better.

      The other option is to fry the livers for a few minutes and then to add some Calvados (French cognac) or brandy; just watch for the flames. The process which is very common in French cooking, is called Flambé during which the alcohol evaporates and what’s left behind is its sweetness.

      1. Hmm, the second option sounds appealing – if I sample enough cognac while preparing and Flambe’ing, I won’t really care what it tastes like!

        1. That would be your 3rd option. Plus, being that Calvados is an apple brandy you don’t have to worry about gluten;-)

      2. IMO all liver is just plain nasty unless you really doll it up. There are a number of good recipes for paté, and braunschweiger or liverwurst are usually pretty good. The additional ingredients in homemade paté change the taste and texture of the liver completely, transforming it into something that’s actually quite delicious.

    4. You should try dessicated liver. uni-liver has tablets of it (from grass fed cattle). No taste, full livery goodness.

  4. On one hand, I like the short cut to increasing testosterone. On the other, I’ll find it difficult to pick the kids up at school if I’m not allowed within 500ft of the grounds anymore. Quite a conundrum.

  5. So you can eat the potatoes warm if they are cooked, cooled, and reheated?

    1. I’ve been doing it for years now with potatoes, bread and non gluten pastas. A pre-diabetic friend tried the method and had lower blood glucose readings than eating the pasta freshly cooked.

    2. I’m really not sure about this one. Reheating the amidon breaks some of the links created through cooking and cooling.

  6. “solar irradiation of the scrotum”… well there goes my keyboard, as I spit my coffee all over it.

    1. LOL, I was just thanking the universe I hadn’t been drinking coffee when I read that one 🙂

  7. Sounds like the next best thing to swimming naked, but solar irradiation of the scrotum takes balls. I’ll try to keep it at about 5 minutes the first few days and work up to 20.

    1. Literally! And I guess females can’t participate in this primal activity.

  8. Isn’t liverwurst made of liver? I think it tastes quite pleasant and totally unlike liver, although hopefully there isn’t anything too toxic producing the taste.

  9. Re: solar irradiation: Just make sure you don’t burn it. 🙂

  10. The body is remarkably good at becoming efficient. So efficient, that an activity can cease to be enough of a stressor to elicit changes in the body. I once read that the exercise the body needs most is the one you’re not currently doing. In the case of anyone currently finding themselves in a situation similar to the hiker above, I’d recommend shaking things up a bit. Try shorter hikes wearing or carrying weight, or mixing in the occasional dash to the next tree or the top of the next rise. Maybe take a week and try something completely different like biking or swimming if that’s accessible to you. Your body will adapt if challenged.

    1. Thanks Bradford! I’m the OP, and your suggestions are just what I was looking for. I actively seek out hills because I love the challenge and the cardio boost. Also, my daily afternoon walks/hikes are in addition to strength training/HIIT I do in the mornings. I like the idea of adding weight to my backpack. I think I’ll try that! I do add sprints to my hikes to keep it interesting, and that is another great suggestion.

    2. So true I took some guests on a hike in my community. The girls that joined me got bored and detoured to build a rock dam. In a nearby stream. At first I was like, don’t do that its cold and muddy. Then I simply joined in to help lift the bigger rocks and engineer a zig zag cascade. It was way more memorable than a walk for all of us.

  11. Oh my, that’s getting pretty close to where the sun don’t shine!

  12. I read a tip to mince liver, freeze it in ice cube trays, then throw a cube in whenever you make a stew or sauce.

    I’m not brave enough to try it because I’m scarred from memories of being regularly made to eat liver & onions as a kid (along with boiled beef tongue and heart).

  13. As far as the liver goes, I’ve done what John mentioned with freezing raw liver and just doing a liver shot in the morning. My best liver trick is to buy ground beef that is 20% organ meats from local farmers. You really do not taste it. I also agree with Mark about the chicken livers. In fact, I just made some on Saturday with bacon and they were delicious. I have also been known to take liver capsules. I definitely notice a difference in my energy levels with regular liver consumption!

  14. Whenever the subject of raw liver consumption comes up, I want to shout THINK TWICE. I contracted campylobacteriosis from adding raw chicken liver to a smoothie. Yes, I’d been regularly consuming raw beef, lamb, and chicken liver for months with nothing but positive, energy-boosting results. Yes, I’d frozen this particular batch of fresh, localyl-sourced liver for a few weeks before consuming it, but this time, the bacteria survived the freeze. I, who hadn’t contracted so much as a cold in years, got very, very ill, and two courses of antibiotics were necessary to wipe out the infection. More than two years later, my digestion is still not 100 percent. Never again for me. Think twice.

    1. +1. Thanks for posting this. Eating raw meat of any kind is risky business, even if you slaughter the animal yourself, which very few people do these days. You not only get bacteria from the animal but also from the processing/packaging plant. Meat handlers aren’t particularly careful because they assume people COOK meat before eating it. I’d be willing to bet that a piece of raw liver looked at under a microscope would be literally crawling with all kinds of bacteria.

      1. I’m glad this is mentioned. I’m new to this blog and reading about people consuming raw liver made me wonder what I missed. Eating raw meat seems like the unhealthiest thing a person can do… even after it’s been frozen.

  15. Googling “clothing optional beach” and “how to improve my upward lotus pose”

  16. Why is there no love for pork liver? I eat pork, beef and chicken liver on weekly rotations. Pork liver kinda taste good – even great when it is bacon wraped. Actually, everything is great when it bacon wraped. Bacon wrapped liver skewers. Game over.

    1. I agree! It’s often cheaper too! We eat it with caramelized onions and bacon and we only cook it 2 minutes and a half. If you overcook it, it becomes inedible. It tastes like crap and it’s unchewable. Also don’t skimp on the salt!

  17. My 8 and 10 year old love their liver slurry… It’s 3oz of raw liver, a few frozen cherries, add raw honey to taste, a little water and blend. They enjoy this every Wednesday and Sunday.

    I can’t say the same for my 13 year old… to avoid the taste, and the arguing, he throws back 6 capsules a day of our liver supplement.

  18. Glad you pointed out that walking and hiking aren’t exercise unless you are unfit. If you are fit, it’s just a casual activity. I can walk for miles, briskly, on a flat surface and only get irritated and bored. It’s just repetitious busywork. I need steep hills and uneven terrain to feel like I’m doing anything but spinning my wheels for nothing. Same goes for “jogging” which i think is one of the worst activities to take up. Walk or run or sprint. Jogging is not hard enough for real physical development but still hard on the body’s joints. Don’t do it. All the joggers I see look exactly the same year after year in my neighborhood. Kind of soft and haggard. The people who actually run, are lean and fit.

  19. When making meatballs, grind up 1/4 lb chicken livers and add them to the mix. You’ll never notice they are there when eating them.

  20. Your testosterone / testicle mention reminded me of this article about LLLT which refers to a study indicating that LLLT increases testosterone when applied to the testicles.

  21. “Beginners to hiking and walking will find a few miles incredibly taxing. For them, it is exercise. But then you adapt, and it becomes easy and relaxing. That’s where I suspect you are. Twenty-five miles a week is excellent activity, but it’s a breeze.”

    And this is the basis of the truth that walking comes naturally to humans. It’s what we do. And we can do it for long periods without it being a big deal.

    That we find it taxing at first is an indication of how far we have fallen from the basic mechanical norms of our bodies.

    But at some point, walking becomes essential to the mind and body. We have to do it or we just don’t feel right.

    1. Try carrying a backpack with a reasonable amount of weight inside (15-20 lbs) is ideal. This will somewhat replicate the weight of gear a through hiker would carry. You will develop core strength and and probably notice overtime that your body will become leaner and tighter. I would suggest reading Dr. Phil Maffetone and heart rate training. Do not get suckered by muscle building. There are many people who are fit but not healthy. Worry about your BMI, BP, resting heart rate and most importantly recovery. Lastly, you live in the Rockies. Make hiking a lifestyle choice. Go snowshoeing in the winter. Read about John Muir. I hope this helps somewhat.

      1. I agree with what you say but I didn’t pose a question and I wasn’t asking for help.

        Elsewhere on this blog I’ve offered the same advice to others regarding wearing a backpack while walking. I often walk to the supermarket just so I can pack home 8-10kgs of groceries.

  22. My last beef liver was (grassfed) yearling, much milder than a more mature one. Quick cook with onions, peas, mushrooms, salt and pepper and too delicious to leave a treat for the Ridgeback.

  23. Liver: Feed beef liver through an old fashioned hand crank meat grinder and mix with ground beef. 1 part liver to 4 or 5 parts beef. It’s a little messy but hides it well in patties or meatballs.

    Testosterone: I’ve been putting vitamin D oil on my knees and elbows to treat mild psoriasis with some success. I wonder if I should put a few drops on my scrotum?

    1. I agree that we can’t taste it if we do that with pork liver. But you don’t need a meat grinder, we use our food processor and it’s doing a perfectly fine job!

  24. My two liver tricks:

    1) Indian spiced, specifically the green sauce (coriander chutney) takes away most of the bitter taste, so I’ll cook my livers in ghee and garam masala (and whatever other Indian spices I have), and add the green sauce while eating.

    2) making chopped liver, but with TONS of garlic and gribbens. Make schmaltz with chopped chicken skin, render with onions, chop livers (and hearts), saute until barely cooked, salt, and eat. I’ll add parmesan for a very un-kosher meal.

  25. Great post Mark! We walk our dog for miles every day, it’s great for him and for us. Like you say, it’s not huge exercise for us as we’re used to it but every little helps right?

  26. Here’s the study that you were looking for, Mark:
    “Ultraviolet Irradiation and Sex Hormones in the Male” by Abraham Myerson and Rudolph Neustadt
    Journal of Nervous & Mental Disease: February 1940 – Volume 91 – Issue 2 – p228

  27. Does the cooking, cooling & reheating really work on gluten free pastas as well? What about quinoa? I know these are not primal, however from years of listening to my body and eating well I have learned that pure buckwheat or quinoa work better for me than (sweet) potatoes, fruit, rice and other sources of carbohydrate, despite my preference for the taste of fruit / sweet potatoes! I’m not into eating potato starch, so it would be great to get some resistant starch via cooled quinoa/ soba noodles!

  28. Would a grow light work on the scrotum idea for the shy amongst us?

  29. I hope the Google satellite doesn’t fly over Mark’s back yard at the opportune moment!

    To the hiker, I think the more likely answer is that the physique you are looking for might not be natural or achievable without pumping iron. Walking will keep you fit and healthy, and I bet you are, to me that’s the goal. Healthy is the new sexy. Don’t know if you are male or female, If you check out leading men in movies from the 20′ and 30’s, especially beach/water scenes, men had natural looking physiques with “enough” muscle to function well, but nobody looked like Arnold or Dwayne the Rock. I tend to think Grok didn’t either.

  30. if you cook your onion in butter and then set it aside when translucent.. cook your liver in BACON grease, quickly on med high just 1-2 min on each side, put liver in baking dish set onions on top cover and put in oven 350 for 45 minutes. SUPER delicious, sweet, bacony. My hubby puts mustard on his, not me. SAVE the leftovers in the fridge for diced liver omelettes (easy to dice when cold) 🙂 ONIONS ARE THE TRICK TO GREAT LIVER! and bacon

  31. I lived in Japan for years and one of my favourite izakaya dishes was sliced raw beef liver dipped in sesame oil and salt with a few chopped green onions. Mammal sashimi. There was even a chicken sashimi restaurant with all manner of incredibly delicious chicken dishes, all raw… I can’t believe I never got sick! At least from the food…

    I’ve been unconvinced that eating meat raw would be a good idea outside of Japan…

    The Japanese surely can’t be the only folks to take food safety super seriously, but I just haven’t seen the evidence yet. Since I live in the UK now, I’ve been making pate instead. Mace seems to be the thing that mellows the less pleasant flavours. Soaking a liver in milk overnight is a traditional way to prep it here in the UK (and probably elsewhere) as well… always seems like a waste of milk to me though.