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: Weight Loss

The Definitive Guide To What Breaks a Fast

One of the most common questions I get is “Does [x] break a fast?”

What they’re really inquiring about is: “Does this interfere with, negate, or nullify the benefits of fasting?”

These benefits include:

Ketosis: Fasting is the quickest way to get into ketosis, an metabolic state characterized by increasing fat burning, fat adaptation, and—in some people—improved cognitive function.

Fat Loss: When you’re fasting, you’re not eating, and not eating is the best way to force your body to burn the fat it already possesses. Fasting also means no additional calories are coming in, and many people find that fasting is a great way to control their calorie intake.

Autophagy: Autophagy, or “self-eating,” is the process by which our cells prune damaged components, maintain proper function, and keep aging at bay. Fasting triggers autophagy. Breaking the fast will stop autophagy.

Let’s go through the most popular queries one by one and figure out how each one affects an intermittent fast. (For questions about what supplements break a fast, check out my post, “What Breaks a Fast: Supplements Edition.”)

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Dear Mark: Antibiotic Recovery, Sprinting on Keto, Preparing for Bad Sleep

For today’s edition of Dear Mark, I’m answering three questions. First up, what can a person do to help their gut recover its barrier function after too many antibiotics? Are there any foods, supplements, or dietary strategies? Second, what can explain rapid fatigue during sprint sessions on a keto diet? Is this simply part of the deal, or are there modifications you can make? And finally, what do I do when I know I’m going to get a bad night’s sleep?

Let’s go:

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The Definitive Guide To Autophagy (and 7 Ways To Induce It)

Biological systems are self-maintaining. They have to be. We don’t have maintenance workers, mechanics, troubleshooters that can “take a look inside” and make sure everything’s running smoothly. Doctors perform a kind of biological maintenance, but even they are working blind from the outside.

No, for life to sustain itself, it has to perform automatic maintenance work on its cells, tissues, organs, and biological processes. One of the most important types of biological maintenance is a process called autophagy.

Autophagy: the word comes from the Greek for “self-eating,” and that’s a very accurate description: Autophagy is when a cell consumes the parts of itself that are damaged or malfunctioning. Lysosomes—members of the innate immune system that also degrade pathogens—degrade the damaged cellular material, making it available for energy and other metabolites.  It’s cellular pruning, and it’s an important part of staving off the worst parts of the aging process.

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The Real Deal On Keto Body Odor

I’m continuing my crusade of keto mythbusting. Recently, there was keto crotch, then keto bloat, and today I’m returning to one of the O.G. myths—keto body odor. Yes, it seems detractors of the keto diet are hell-bent on making you think your body will become a stinky, bloated mess if you dare to drop your carbs below 50 grams per day…but is it true? Here’s the spoiler: Yes, people in online keto diet forums occasionally complain about an unpleasant change in body odor when they first go keto. There is no scientific evidence that it actually happens, nor a clear, compelling explanation for why it would. Moreover, the anecdotal (and it’s all anecdotal) evidence suggests that if it does occur, it is rare and temporary. In other words, the whole idea of keto body odor seems to be exaggerated—shocking, I know.   That said, significant dietary changes can result in other physiological changes that may manifest in a variety of ways. Since nobody wants to be the stinky kid, let’s take this opportunity to look at what might be plausible about keto body odor and what to do if you think you’ve been afflicted.   What Causes Body Odor? First, let’s clarify what’s meant by “body odor.” In the medical literature, the term is used in reference to aromas associated with breath, urine, feces, vaginal secretions, sweat (usually from the axilla, or armpits), and general bodily essence as it were. Because it’s such a broad term, the causes are also extremely varied. For the purposes of this post, I’m going to use the term “body odor” to mean aromas from sweat and general bodily funk, since that’s what’s usually meant by keto body odor. Body odor arises when odorless compounds leave the body through glands in the skin and interact with microbes living on the skin’s surface. The microbes then release chemical compounds—what we actually detect as body odor. Typically, commercial deodorants target both pieces of the equation by using antiperspirants to minimize the excretion of the odor precursors and by creating an unfavorable environment for the microbes living on the skin. There is also a genetic component to how much individuals secrete compounds that cause body odor. Although a huge industry is built around trying to help people mask their natural odors—and suggesting that body odor is always the result of poor hygiene—bodily scents are actually quite important. Just as other animals do, humans use olfactory cues for recognizing kin, making judgments about others’ personality traits and attractiveness, and even for detecting fertility. Although we rarely recognize it, the data suggests that smell probably factors into all our face-to-face social interactions. Body odor can also result from illness. Before the use of sophisticated modern disease detection techniques, doctors were taught to use their sniffers as a diagnostic tool. Even today, smell can be an important clue that an individual is unwell. Often these odors emanate from the breath or urine, but certain infectious and metabolic diseases can be associated with … Continue reading “The Real Deal On Keto Body Odor”

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Dear Mark: Protein Efficiency in Seniors, Earned Carbs, Hardgainer with Limited Time

For this week’s edition of Dear Mark, I’m answering three questions from readers. First, is the reduced protein efficiency in older adults due to inactivity, or is it something inherent to the aging process, or both? Second, how does a person know if they’ve actually “earned” any carbs? Does everyone on a keto diet earn carbs by virtue of exercising, or is there more to it? And finally, how can a hardgainer with a packed schedule all week long and limited gym time maintain what little muscle mass he’s managed to gain?

Let’s find out:

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The Curious Phenomenon of “Keto Crotch”

I have a confession to make: I, Mark Sisson, suffer from keto crotch.

It’s embarrassing, really. I thought maybe it was just the change in climate moving from Malibu to Miami—the humidity, the heat, the fact that I’m paddling and swimming more often now. There’s a whole lot of moisture down there. Perpetual steaminess.

But then I met up with my writing partner and good pal Brad Kearns, who’s been working with me on my upcoming book. Brad lives in Northern California, which is far from hot or humid right now. He’s also a staunch keto guy most of the time, and, well, let’s just say I could smell him before I could see him. We met up at a coffee shop and cleared out everyone in a fifteen foot radius. We sampled a new exogenous ketone product he’s been trying and not one, not two, but three separate individuals approached to inquire if we were salmon fishermen.

Okay, let’s get serious. (And, yes—to address some reader confusion there—the above is pure satire.) Does “keto crotch” really exist? And, if it does, what can you do to prevent it?

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