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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