Meet Mark

Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...

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Category: Diet & Nutrition

9 Factors That Influence Testosterone Levels

In the last several weeks testosterone has come up on a pretty regular basis. I’ve written about it before, of course, but there’s something about the novel elements (e.g. solar irradiation for certain choice body parts) in recent conversations that’s kept the exchange going.  I thought I’d pull back from the peripheral findings a bit today and re-center the discussion.

As you know, testosterone plays a pivotal role not just for libido levels (although we won’t leave that out), but also for bone density, protein synthesis and muscle building, hair growth, estrogen production, red blood cell production, sperm production—amid other key functions in the body (for men and women by the way).

So, what are some factors that influence testosterone levels for the better and worse for both genders? What are the mechanisms behind these associations? And how do they relate to a healthy Primal life?

Let’s dig in…

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Doing Keto the Right Way: An Hour with Aubrey Marcus

A couple of weeks ago I sat down with entrepreneur extraordinaire, multi-sport athlete, and consciousness explorer, Aubrey Marcus, for an in-depth and entertaining discussion of everything from hangover cures to keto philosophy.

Marcus has always been one of my favorite people to talk with, and that morning in my backyard was no exception. We covered all things keto—from the mistakes people make in bottoming out their carbs instantaneously to the advantages of stair-stepping the process. I had a chance to share about my upcoming Keto Reset Diet book as well as personal details of my own experience with the keto state. Aubrey offered his latest favorite recipes (inspired by Primal Kitchen® products, no less!), and we talked in full but casual detail how keto dives set us up for genuine, lasting metabolic flexibility and overall health. There’s a lot of science and plenty of laughs here. I hope you enjoy, everybody!

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Two Final (and Favorite) Adaptogens: Rhodiola Rosea and Bacopa Monnieri

I’ve taken up the subject of adaptogens over the last several weeks, and today I’m wrapping it up with two of my favorites: Rhodiola rosea and Bacopa monnieri.

Primal aficionados from way back will know that I’m a big fan of Rhodiola rosea. It’s an integral component of one of the original Primal Blueprint supplements, Primal Calm. It’s a formula I put together for my own needs and eventually decided to offer in the supplement line. (That seems to be how I come up with things, I suppose….) I’ve written in the past about stress being one of the issues I’m still working on in my Primal life, and adaptogens have been a useful tool I’ve employed. Living with an ancestral template doesn’t preclude being scientifically resourceful. 

But let’s dig into these final two players….

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Dear Mark: Grok’s Terrible Genes; Fasting, Starvation, and Metabolism

For today’s edition of Dear Mark, I’m answering two questions from readers. The first one concerns a study I linked to in this week’s Weekend Link Love. It appears to suggest that ancient humans had worse genes than modern humans have, that they were at greater risk for many different disorders and diseases. How can this be? Last but not least, Pierre expresses skepticism at the notion of fasting or starvation causing metabolic slowdowns. I agree, but only to a point, and I explain why.

Let’s go:

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Is Keto Bad for the Thyroid?

Keto is fantastic, everyone says. It’s a great way to lose weight, improve cognition, and stave off degenerative disease. It may help your performance in the gym and on the track. It could even give Grandpa some respite from Alzheimer’s.

But it’s hell on your thyroid. Right?

Keto detractors and proponents alike often warn that remaining in ketosis will tank your thyroid. The thyroid’s an important gland, exerting major influence over essential systems like fertility, energy, metabolism, body temperature regulation, blood lipids, and general wellness. It controls the metabolic rate of every organ in the body. We want it working well, so this is a major blow to keto—if the criticism holds true. Fortunately, there’s much more to this story.

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Dear Mark: Obesity as “First World Problem”?

For today’s edition of Dear Mark, I’m not so much answering a direct question as I am riffing on an offhand comment. In the comments from last week’s post on weight loss culture, someone mentioned obesity being a “first world problem.” It made me think more deeply about the issue.

In a literal sense, yes. Obesity is often a first-world problem. If your primary concern is figuring out how to stop yourself from eating too much food, you’ve got the kind of problems starving kids in developing countries would love to have.

Yet, industrial food has a long reach. The island nations of Nauru, Micronesia, Tonga, Cook Islands, and Niue are the top 5 fattest countries in the world—even though they aren’t “first world”—because they rely almost entirely on imported, industrial food.

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