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...

Tell Me More
Stay Connected

Tag: dear mark

Dear Mark: Ketosis and Testosterone, Dehydration Hormesis, and Isomalto-Oligosaccharides

For today’s edition of Dear Mark, I’m answering three questions. The first one concerns a potentially combative and controversial topic: ketogenic diets. What’s the deal with their effect on testosterone? You can find keto anecdotes across the web both inspiring and flaccid, but what, if anything, does the science say? Next, might there be a way to derive beneficial hormetic effects from acute bouts of dehydration? It seems like every other stressor can actually make a person stronger, so perhaps an otherwise wholly negative one like dehydration might as well. And finally, is the prebiotic fiber known as isomalto-oligosaccharide safe and/or good to eat?

Let’s go:

Read More

Dear Mark: Exercising (and Eating) in the Heat; Post-Antibiotics Gut Health Support

For today’s edition of Dear Mark, I’m answering a pair of questions from you folks. First up, what with the crazy heat wave sweeping much of the planet, a reader writes in asking about the best way to eat and move in the heat. Should you cease all activity? Should you modify your normal movement patterns and eat and drink differently to keep the heat at bay? Read on to find out. Next, how should a person deal with and support the post-antibiotics gut biome? What can we do to mitigate the negative effects broad-spectrum antibiotics have on our gut bacteria?

Let’s go:

Read More

Dear Mark: Melatonin Supplementation, Overcoming Previous Poor Health, and Is HIIT Too Stressful for Women?

For today’s edition of Dear Mark, I’m answering three questions from readers. First up, what’s the deal, exactly, with melatonin supplementation? Is it harmful? Dangerous? Will it impair our body’s own production of melatonin? Second, a reader wonders whether his past poor health decisions are sabotaging his health today. Even if he’s feeling great now, shouldn’t he worry about the permanent effects from all that pizza he ate and sleep he didn’t get back in the day? And finally, some people recommend against sprinting or high intensity interval training for women. Is it true? Should women only go gently into the gym to tread lightly on ellipticals and avoid all that sweaty, icky fast stuff?

Let’s find out:

Read More

Dear Mark: Balancing Strength with Military Conditioning; Sitting in a Squat Position

For today’s edition of Dear Mark, I’m answering two questions from readers. First comes from William, an officer in the Navy who likes lifting heavy but also needs to score well on the physical fitness assessment, which involves a 1.5 mile run, pushups, and pullups. His taste for basic 5×5 strength work has left his running performance lacking. What can he do to improve the run without eating into his strength numbers? After that, I explore whether sitting on a footstool or medicine mall in the squat position is better than just sitting in normal chair.

Let’s go:

Read More

Dear Mark: Nutrient Deficiencies and Fatigue, Anxiety, CLA Supplements, and Plant-Derived Oils

For today’s edition of Dear Mark, I’m answering four questions from readers. First up, are there any specific nutrient deficiencies that can contribute to fatigue? Which minerals and vitamins should you shore up when experiencing malaise? Next, what’s the deal with anxiety? Does it serve an evolutionary purpose, or is it just a pathological condition? Third, is there a place for conjugated linoleic acid (CLA) supplementation in a healthy diet and lifestyle? I dig into the studies to help you decide. And finally, what plant-derived oils beside just avocado oil are good to use when staying Primal?

Let’s go:

Read More

Dear Mark: The Linoleic Acid Content of Phosphatidylserine, and Optimal Sleeping Position/Location

For today’s edition of Dear Mark, we’ve got a two-parter. First up, what’s the deal with phosphatidylserine, one of the (most crucial) ingredients in Primal Calm? It’s a derivative of linoleic acid-rich oil, so what’s it doing in one of my supplements? Find out if you need to worry about undue levels of linoleic acid from taking Primal Calm. Then, are there any benefits to sleeping on one’s back as opposed to on one’s side? And how about sleeping outdoors under the stars and being woken up by the birds — is there any reliable reason that would improve the quality of our sleep and help us wake up more energized?

Let’s find out:

Read More

Dear Mark: Your Milk Questions Answered

For today’s Dear Mark, I’m responding to as many of the questions and concerns relayed in the comment section of last week’s raw milk post. You guys had a lot of them, ranging from whether raw milk can help with eczema and adult asthma, if homogenization is dangerous, why raw milk might taste and smell fishy, to how many people get sick from pasteurized milk. I also respond to reports of raw milk not being a panacea for immune health, and even an active impediment to it.

Lots of ground is covered today, so let’s get right to it.

Here we go:

Is homogenization dangerous?

Read More

Dear Mark: Sugar for Stress Relief, and Weight Loss Releasing Toxins

For today’s edition of Dear Mark, I’m answering two questions. First, a new study out is one of the first (and maybe only) to show that acute sugar consumption can reduce the normal cortisol increase we experience in times of stress. Interesting stuff, eh? Find out whether I think this is a good thing, a potentially useful “hack”, or, given our collective tendency to overthink things and embroil ourselves in stress stews, a recipe for disaster. Next, we’ve all heard that weight loss releases stored toxins and environmental pollutants into our bodies, but is there any science that actually shows this is happening in people losing weight? And if we are releasing toxins by losing body fat, does that mean keeping the weight on is actually healthier? Find out down below.

Let’s go:

Read More

Dear Mark: High HbA1c with Low Blood Sugar; Muscle Glycogen: Is It Local?; and Ketogenic Mosquito Repellant

For today’s edition of Dear Mark, we’ve got a three-parter. First, what could possibly explain an ardent and otherwise healthy low-carber with stellar postprandial (i.e. after a meal) blood sugar levels showing up with an HbA1c reading indicative of pre-diabetes? Who’s messing up — the test or Nancy herself? Next, that pastured chicken you’re about to eat may very well be local, but what about the glycogen in your quads? Is a muscle’s glycogen usable only by that muscle, or can it be shipped to nearby muscles as well? And finally, a reader reports suddenly becoming unattractive to mosquitoes upon adopting a low-carb diet and bouncing in and out of ketosis. Is he imagining things or is there a potential mechanism at play?

Let’s go:

Read More

Dear Mark: How to Give a Baby Probiotics, and Pre- and Post-Meal Exercise

For today’s edition of Dear Mark, we’ve got a two-parter. First, in light of the recent paper showing that Lactobacillus rhamnosus probiotics given during the first six months of life protects against the development of conditions like ADHD and Asperger’s by age 13, how do you actually give the probiotics to a breastfed baby? It’s pretty easy, as you’ll find. And then, given that acute exercise performed before or after meals seems to change the metabolic response to those meals, would I recommend actually working out every time a person eats? It sounds a little excessive, but it might actually be a good move with some positive effects for people who have trouble with insulin and glucose issues.

Let’s go:

Read More

Join Over 300,000 Subscribers!

Signup and get:

Primal Blueprint Fitness plus 7 other eBooks
7-Day Course on Primal Fundamentals
Special Offers and More!