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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Tag: body fat

Dear Mark: Does Physical Activity Affect Obesity Risk?

For today’s edition of Dear Mark, I’m answering one question from a reader. It concerns the effects of physical activity on obesity.

This is an evergreen topic, a constant in the queries I receive. Is exercise necessary for weight loss? Does physical activity improve body weight? Is exercise all about burning calories, or is there something else going on?

Let’s get to it:

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The Definitive Guide to Metabolic Flexibility

Metabolic flexibility is the capacity to match fuel oxidation to fuel availability—or switch between burning carbs and burning fat. Someone with great metabolic flexibility can burn carbs when they eat them. They can burn fat when they eat it (or when they don’t eat at all). They can switch between carbohydrate metabolism and fat metabolism with relative ease. All those people who can “eat whatever they want” most likely have excellent metabolic flexibility. So, why does it really matter, and how does it happen? Let’s get into the weeds today.

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Dear Mark: Saturated Fat More Harmful to Liver Than Sugar?

For today’s Dear Mark, I’m answering just one question from a reader. What are we to make of the new study purporting to show that saturated fat is the most harmful substance a liver can encounter? Should we remove all traces of it from our diets? Should we eat pure sugar? Quaff soybean oil? How relevant is an overfeeding study to a community of people dedicated to eating a sustainable, weight-reducing or -maintaining diet that includes saturated fat?

Let’s find out:

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11 (Non-Dietary) Actions That Enhance Insulin Sensitivity

Insulin does a lot of important things for us. It pulls glucose from the blood and fritters it away into our cells to be burned for energy or stored as glycogen. It prevents hyperglycemic toxicity to neurons, pancreatic cells, the arterial walls and the generation of excessive levels of reactive oxygen species. It even promotes muscle protein synthesis and helps augment muscular hypertrophy, especially following resistance training. Clearly, we need insulin. Without it, we’d die, as type 1 diabetics readily do without an exogenous source.

But this process goes off the rails when our cells become resistant to the effect of insulin over time. We secrete too much. Our levels remain elevated. It becomes harder to burn body fat. In fact, we end up in even more efficient fat storage mode.

I’ve shared about nutritional means to enhance insulin sensitivity in the past. What about other non-dietary strategies?

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Intermittent Fasting for Women: What We Know Now

This is an updated version of a Dear Mark column from 2012. You can find the original version archived here. The below has been completely updated for 2018.

The blank slate hypothesis has fallen. Everyone comes into this world imbued with attributes, characteristics, and predilections that are uniquely theirs. We’re all humans, but we’re a diverse bunch, and that makes it interesting. And though it also makes giving cookie cutter health advice impossible, I just take that as an opportunity to stand out from the crowd and provide actionable advice that genuinely helps real people.

A perfect example is biological sex. Anyone who’s lived with the opposite sex, been married, or had kids of different sexes knows that males and females are different—on average.

There’s a ton of overlap, don’t get me wrong.

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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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Is There a Problem with Weight Loss Culture?

I recently read a piece from the New York Times in which the author, Taffy Brodesser-Akner, recounts her lifelong struggle with dieting and body acceptance and her relationship to food. She tackles the failure of most “diets,” the fat acceptance movement, the Weight Watchers-as-support-group phenomenon, the Oprah Winfrey body weight yo-yoing. What makes it an effective article is that, rather than cast herself as dispassionate journalist reporting the facts, Akner is elbows deep. She herself is the subject as much as anything else. It’s a powerful article. Go read it.

The article doesn’t come to a neat conclusion. There’s no prescription at the end. It meanders. It explores. It’s messy. I think that’s exactly how most people feel when trying to tackle this diet/health/bodyweight/eating thing: confused, lost, conflicted, overwhelmed. Go look at the comment section from the article, and you’ll see that pretty much everyone got something different from it.

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CrossFit Training: How to Lose Fat with Primal

Note: Many of you have written to me wondering about my newfound obsession with CrossFit. I’m responding to a steady stream of requests from CFers who want to do Primal but have been led to believe that the two are incompatible. Even if you have no interest in CrossFit, understand that much of the advice contained in this series also applies to people following a different training path.

As much as CrossFitters claim to concern themselves primarily with increasing physical performance and work capacity across broad modal domains, they also want to lose body fat. There’s nothing wrong or superficial about that, mind you. Excess body fat is unnecessary and, depending on the quantity and location, dangerous to your long-term health. It also impedes performance, acting as dead weight. We have every reason to want to lose body fat.

CrossFit is well-known for leaning people out. But there’s also a small but significant portion of people who struggle to lose body fat despite—or perhaps because of—hitting the box religiously and doing all the workouts. This post is for them.

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Cool Things You Notice Happening Once You Start to Lose Weight

Most people come to the Primal Blueprint because they want to lose weight. Ask any purveyor of a specific diet and they’ll say much the same thing. The majority of people are interested in dropping body fat, looking good naked, and fitting into their clothes. The interest in overall health, fitness, and lifestyle tends to develop organically out of that. Come for the weight loss, stay for the blue-blocking goggles.

There’s a tendency to view weight loss as superficial compared to the other stuff. That’s a mistake. Weight loss isn’t just about belt notches and positive experiences with mirrors. It confers measurable and, most importantly, tangible benefits to health, happiness, and daily functionality almost immediately. Fat loss, it turns out, isn’t a flighty pursuit. It solves a lot of serious problems and makes some really cool things happen.

Like what?

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How Long Does It Take for Fitness Benefits to Show?

A big reason most people never stick to a serious exercise routine is that the benefits most people are interested in take a while to appear. Fat loss, muscle gain, boosts to strength, speed, and stamina—these physical manifestations of training adherence can take weeks and even months to show. That’s plenty of time for folks to give up, convinced exercise is just not for them.

I get it. I do. But that’s not a valid excuse for not exercising. You know it’s important, you know what the benefits are, and I’m not going to sugarcoat things: training is not optional.

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