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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Dear Mark: PUFA/SFA Swap, Ticks and Meat Allergy, HIIT for Older Men

For today’s edition of Dear Mark, I’m doing three quick topics. First, what are we to make of the studies in which replacing saturated fat and trans-fat with omega-3 and omega-6 polyunsaturated fat seems to reduce heart disease? Second, although red meat is nutrient dense and generally a more interesting option than plain chicken breast, some people have legit red meat allergies (tick-induced or otherwise). What do I think about that and the tick situation in general? And third, is HIIT an effective (and safe) option for middle-aged men?

Let’s go:

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Dear Mark: Diet to Get Lean, Exercise to Get Healthy?

For today’s edition of Dear Mark, I’ll be discussing the role of exercise alone in weight and fat loss. If it seems like I’ve been harping on this same topic for a couple weeks now, it’s only because it’s so important to identify both the mainstream (“You must exercise ten minutes for each Oreo you eat.”) and alternative misconceptions (“Exercise has no effect on body composition.”) about exercise. Exercise—all by itself—actually can help you lose body fat, even if it has less to do with “burning calories” than other factors.

Let’s take a look:

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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: Marine Fat Sources, Not Gaining/Losing, Keto Breastfeeding

For today’s edition of Dear Mark, I’m answering three questions. First, what are some less expensive sources of marine fat high in omega-3s? Is canned salmon a good, safe, effective option? Second, a reader is training hard, eating low-carb/keto, doing IF, and feels pretty good despite not losing or gaining any weight? What should she do? What could she be doing wrong? And third, should you go keto while nursing?

Let’s go:

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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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