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: Carbs

Dear Mark: Potato Diet, Lean Gains, EVOO/Butter/Ghee, Exogenous Ketones, and Early IFing

For today’s edition of Dear Mark, I’m answering several questions drawn from the comment board of last week’s post on fasting vs carb restriction. First, how do I square my recommendations with the successful reports of potato dieters losing weight on a high-carb tuber diet? Second, is Leangains optimal for mass gain? Third, how do I use extra virgin olive oil, butter, and ghee? Fourth, could exogenous ketones help a man with dementia, MS, and seizures? Fifth, how should a woman with stalled weight loss integrate fasting?

Let’s go:

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Fasting versus Carb Restriction: Which Works Better for What Scenarios

Both fasting and carb-restriction appear to operate along similar physiological pathways. Both lower carbs. Both increase fat-adaptation. Both have the potential to get you into ketosis. Both lower insulin and blood sugar.

But is one better than the other? Are there certain scenarios in which an intermittent fasting protocol works better than a low-carb diet, and vice versa?

Let’s find out if the distinction matters.

And what scenarios are most impacted by any difference.

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8 Misconceptions About Fiber

The tricky thing about fiber is that it’s not a monolith. There are dozens of varieties. Some of them perform similar functions in the body, but others have extremely unique effects. Some rend your colonic lining to stimulate lubrication. Some turn into gelatinous slurries. But we can’t talk about fiber without understanding that the word describes a variety of compounds. As such, anyone making declarative statements about “fiber” without differentiating between the different types and their effects isn’t being accurate (except for me in that exact sentence).

This leads to a lot of confusion. People make blanket statements that might be true for some types of fibers and incorrect for others. 

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Can a Vegan Go Keto?

Absolutely! Anyone can go keto, including vegans. They might not be able to stay vegan, but they can certainly go keto. Nothing stopping them. The more the merrier.

Jokes aside. Can someone go keto while remaining vegan?

That’s a tougher problem. Not intractable. But real tough.

Why is it so hard?

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Periodizing Nutrition: The High Fat Approach

I’m excited to introduce a guest post from an elite athlete in the midst of an incredible ultrarunning career. Believe me, not many athletes can write—or do much of anything except perform and veg out on the couch recovering before the next workout. Zach Bitter, record setting ultramarathon runner, is different, as readers of his popular blog already know. Zach holds the American record for the 100-mile run of 11 hours, 47 minutes. That’s running all day—400 laps around a regulation track—at seven-minute per mile pace. Go try to run a single mile in seven minutes to gain a full appreciation for his supreme effort.

Zach has achieved some notoriety in the ultra scene as a dedicated fat-fueled athlete. (You can read his story here.) He dabbles in keto during his base building training cycles, believing that it speeds recovery and reduces the stress impact of his workouts. His fueling strategy for competition is more nuanced, and he has a lot of important things to say on the matter. His post offers insightful commentary about periodization of nutrition. Here is a quick sound bite from Zach about his big picture goals with becoming highly fat- and keto-adapted: “I strongly believe that the less you have to fuel during a race, the better.” Enjoy this message from Zach, and we hope to check in with him again in the future.

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6 Older Studies That Got No Love but Should Have

“Back in my day, science came harder. We may not have had your fancy longitudinal data analyzing software, your iterated pool of available data upon which to build, or your worldwide network of instantaneous communication and information transmission, but we rolled up our sleeves and got to work just the same. And man did we do some science and discover some things. Boy, you don’t even know the half of it.”

When I turn my sights back to older research, I realize that a lot of this stuff we “discover” in health and nutrition has already been found, or at least hinted at. Today, I’m going to explore some of my favorite research from years past that, if posted to Science Daily or linked on Twitter today, would get a huge response.

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