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: Fitness

15 Reasons Not to Trust That Latest Nutritional Study

Nutritional studies are often the best we’ve got. Without them, we’d be plucking anecdotes from a swirling vortex of hearsay, old wives’ tales, and prejudices. Some actionable information would definitely emerge, but we wouldn’t have the broader vision and clarity of thinking offered by the scientific method. Most of them are deeply flawed, though. And to know which ones are worth incorporating into your vision of reality and which only obfuscate and further muddy the waters, you have to know what to watch out for.

Today, I’m going to discuss many of the reasons you shouldn’t trust the latest nutritional study without looking past the headlines.

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Dear Mark: Do I Need to Eat More, Testosterone Levels, HRV and Carbs

For today’s edition of Dear Mark, I’m answering three reader questions. First, if things are going well on a relatively low-calorie intake, should you just keep on keepin’ on or should you increase food intake to “get ahead” of your needs? Next, what’s the deal with a study showing a high-carb diet is better for testosterone levels than a high-protein one? What does this mean for your Primal way of eating? And finally, can an improvement in heart rate variability after a carb refeed indicate a greater need for carbs?

Let’s go:

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How Going Primal Can Help With 5 Common Genetic Mutations

As I mentioned earlier this year, our personal ancestry can help determine how we respond to certain dietary, behavior, exercise, and lifestyle patterns. The big question remaining is this: does going Primal mesh with some of the more common polymorphisms? Yes. The Primal Blueprint is a living document. Its foundation rests on pre-agricultural human evolution, but by remaining flexible and offering ample room for personalization, it acknowledges the fact that evolution has continued to occur.

Let’s take a look at five genetic mutations and how the Primal way of eating, living, and moving can help mitigate their downsides.

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8 Primal Rules for Building Better Bones

Strip away the skin, fascia, muscles, organs, blood vessels of a human and you’re left with the bones: the foundation providing passive structural support. Many people accept that we can affect and even control the health of the rest of our tissues. Muscles? Just lift. Cardiovascular system? Do some cardio and lose weight. Teeth? Stop sugar. But bones just wear down the older you get. Everyone knows it. And sometimes bones just break. There’s nothing you can to prevent it and nothing you can do to improve your healing except wait and hope. If you want stronger bones, you’ll need some pharmacological assistance provided by a white coat-clad adult wielding a prescription pad.

But bones aren’t inert. They are living metabolic tissue. And though we can’t tell them what to do directly, they grow—or diminish—in response to the signals we send. What kind of signals should we be sending?

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Dear Mark: Staying Aerobic, Glycogen Depletion, and Sleep-Low for Strength Training?

For today’s edition of Dear Mark, I’m answering three reader questions. First, do anaerobic workouts—sprints, lifting, etc.—interfere with your ability to become a fat-burning, aerobic beast, or can you integrate them? Next, in last week’s post I talked a lot about glycogen depletion in the context of the “sleep-low” carb partitioning. How can we actually achieve this without doing the intense intervals the elite triathletes were doing in the study? And finally, does carb-fasting after strength training also work?

Let’s go:

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Should You Sleep-Low to Boost Performance?

Thought experiment time. Say you train hard, hard enough to deplete a signifiant amount of glycogen. Your muscles are empty, sensitive to the effects of insulin, and screaming for a couple potatoes to refill glycogen. What do you do?

In most circles, the answer is to eat those potatoes and refill those glycogen stores. And why not? The post-workout period is a special window of opportunity for eating a bunch of carbs and having them go to the right places with minimal insulin required. They won’t contribute to fat storage. They’ll go straight to your muscles. Restocking glycogen sets your muscles up to repeat the hard work and keep up with your training. It makes sense.

What if you didn’t eat the potatoes after a hard workout? What if you abstained from carbs entirely after a glycogen-depleting workout? What if you just went to bed without any (carbs in your) supper? What if you were an elite athlete and skipped the carbs?

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