Dear Mark: Too Much Coconut Milk, Donating Blood, De Novo Lipogenesis, and Distilled Water

The milk of the coconut enjoys an exalted position among in our community. We prize its ketone-generating prowess. We marvel at how it laughs off bile salts with nary a care and goes straight to digestion. Its tendency to shoulder aside longer-chain fats in the acetyl-CoA line doesn’t even come off as a jerk move. And when we find ourselves at southeast Asian eateries, coconut milk-based dishes are always a dependable option. It forms the basis of smoothies, curries, and refreshing summer drinks. Yet one question remains: does such a thing as too much coconut milk exist?

Find out the answer to that question, plus several more, in this week’s edition of Dear Mark. Let’s get to it:

How much is too much coconut milk? I’m addicted to the stuff.


When you find yourself skulking around town, glancing furtively up at passers-by as you sip out of a can of coconut milk wrapped in a paper bag, you’ve had too much. If you find yourself holed up in a dingy Albuquerque motel room littered with empty tetra-paks of Aroy-D, you’ve got a problem. Other than that, as long as you’re not gaining unwanted body fat, or drinking so much that it displaces other, more nutrient-dense foods in your diet, you’re probably fine.

If you’re curious what I think is the upper limit of sane consumption for other foods like bacon, butter, chocolate, coffee, eggs, nuts and many others, check out How Much is Too Much? and How Much is Too Much? – Round 2.

Dear Mark,

I donate blood regularly and, as you may be aware, post-donation, one is expected to consume sugar in it’s purest form. They provide cookies and fruit juices and all sorts of things which I normally avoid since having gone Primal. So my question is: is there a better, more Primal method, for dealing with suddenly losing a pint of blood, or should I continue eating the sugar?



From what I understand, the juice is there primarily to get your blood volume back up after a draining, and the snacks are there to get you to sit down, relax, and take a load off for fifteen minutes to recuperate before rushing off and getting into trouble in your potentially-lightheaded state. Since you only have about a teaspoon of sugar in your blood at any one time, a piece of fruit (or even the juice) is plenty to replace anything that you’re missing. As for the fluids, regular water is fine. Coconut water is another good option.

You should probably drink some water beforehand, too, to prepare for the upcoming draining.

Ultimately, there’s nothing magic about the cookies and OJ.

Hi Mark – Great site and book.

I have long been puzzled by the following question: Can excess high blood glucose become fat even if you have glycogen stores available?

Let’s say I have enough muscle to hold 500g of glucose as glycogen and right now only 100g is full. General opinion seems to say whatever excess glucose I take in beyond immediate needs will automatically convert to muscle glycogen until the 500g is full.

However, experience tells me that if you have very high blood glucose some it can be converted to fat *even* if some of it also converts to muscle glycogen, so that eating carbs is not just a simple accounting problem.

Does this seem right to you?



Studies are fairly consistent that de novo lipogenesis (or conversion into fat) only occurs when glycogen stores are topped off. That is, so long as you’ve got spaces open in your muscles for glucose to be stored as glycogen, postprandial de novo lipogenesis will rarely – if ever – occur to any significant degree. Putting glucose in muscle is one of insulin’s favorite activities; it’s easier to do that than convert it into fat. So, all done, right? That wraps up that?

Ha, if only it were that easy. If only modern humans existed in a state of depleted and then repleted glycogen. If only we weren’t a society of carb-eating, couch-sitting apes with perpetually topped-off glycogen stores. Then, maybe we wouldn’t have to worry about dietary carbs causing so many problems.

We’re not, though. Our sedentary muscles are, by and large, topped off with glycogen around the clock. Oh, sure, we might get so dependent on sugar for energy that walking to our car, clicking the remote control, and reaching for another sip of whatever we’re drinking uses up some muscle glycogen (instead of fat), but most of us are not the insulin-sensitive “healthy young men” with 11-14% body fat, “one of whom is a competitive swimmer” featured in that de novo lipogenesis study (PDF). Most of us can’t handle 500 grams of carbohydrates and many of us are insulin-resistant. And although there are no real studies examining the prevalence of de novo lipogenesis in the insulin-resistant and glycogen-replete, there are hints.

Take this 2011 study, which found that depleting glycogen stores with exercise reduced postprandial de novo lipogenesis in subjects fed a carb-rich meal. Compared to the non-exercising control group, the exercisers experienced three-fold higher postprandial muscle glycogen synthesis (more dietary glucose became muscle glycogen) and a 40% reduction in hepatic triglyceride synthesis (less liver fat produced). It’s clear, then, that studies performed using lean, healthy, and/or glycogen-depleted subjects don’t tell the entire story for everyone else.

As to your situation, you probably don’t have a team of researchers examining the glycogen content of your muscles before and after a meal. You’re just kinda eyeballing things, using the mirror and your subective impression of how things are going or not going – like all of us. So I don’t have a hard answer for you, unfortunately. I don’t know exactly what your capacity for de novo lipogenesis looks like, because that depends on the degree of glycogen depletion, the carb load, your insulin sensitivity, and plenty of other variables. What I can tell you is that any available space in your muscles for glycogen will be filled by incoming dietary carbohydrate before de novo lipogenesis occurs.

The question becomes: are you truly glycogen depleted? Most people aren’t.


I read your blog alot and hand out in the forums occasionally. A topic that has come up for me lately is whether distilled water is good for you to drink. My father in law (chiropractor) swears by it, but a guy I know at work (biology Major) is adamantly against it.

Do you have any thoughts on it or any legitimate articles you could point me to that are not supported by distillers or bottled water companies.

Cheers. Thanks.


I don’t really have a dog in this fight, and I’m unaware of any studies dealing directly with the safety or danger of drinking distilled water, but there is evidence that drinking mineral water (whether it’s high mineral tap water, well water, or bottled mineral water) confers significant health benefits. Let’s take a look at some evidence of minerals in drinking water affecting health, shall we?

Of course, most of these studies are epidemiological, and thus inconclusive, but they point to a possible effect. My thinking? It’s not that distilled water is bad for you. It’s that minerals are good for you, and drinking water was a common, ancestral source of minerals for most of human history. Much like the modern obsession with sterility (hand sanitizers on keychains, etc.) has robbed us of important exposure to dirt and microbes, perhaps our obsession with “purified” water has robbed us of vital minerals.

I still drink tap water, but I also keep a bottle of trace mineral drops on hand. A couple drops in a glass of water, a half teaspoon in a jug, and you’ve effectively remineralized your water (and anything you use that water to cook). For example, if you’re going to be cooking up some white rice (for whatever reason), a teaspoon of minerals in the cooking water will make the nutrient-poor grain nominally more nutrient-dense.

That’s it for today. Questions, comments, concerns? Leave them in the comment section. Thanks for reading!

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About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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