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
July 02, 2012

Dear Mark: How Much Glucose Does Your Brain Really Need?

By Mark Sisson
153 Comments

We now know that the oft-repeated “your brain only runs on glucose!” is wrong. I’ve mentioned it before, and anyone who’s taken the time to get fat-adapted on a low-carb Primal eating plan intuitively knows that your brain doesn’t need piles of glucose to work, because, well, they’re using their brain to read this sentence. Obviously, you eventually adapt and find you have sufficient (if not much improved) cognition without all those carbs. That said, some glucose is required, and that’s where people get tripped up. “Glucose is required” sounds an awful lot like “your brain only uses glucose” which usually leads to “you need lots of carbs to provide that glucose.” And that’s the question today’s edition of “Dear Mark” finds itself attempting to answer: how much glucose is required?

Let’s get to it.

Hi Mark,

I have a little problem. Even though I’m able to function at work, maintain conversations, and go about my daily life without having segments of my brain suddenly stop working while eating Primal, my friends are worried about my brain. All they know is that the brain needs glucose. What can I tell them? How much glucose does my brain actually require to keep working?

Thanks,

Frank

I wouldn’t be too hard on your friends. They mean well and it’s a common misconception. Instead of chiding them, rubbing their faces in the knowledge that you can function quite adequately on a high-fat diet, educate them.

How much glucose the brain requires depends on the context. There’s not one single answer.

If you’re on a very high fat, very low carb diet – like a traditional Inuit diet – your brain will eventually be able to use fat-derived ketones for about 50-75% of its energy requirements. Most ketones are produced in the liver, but astrocytes in the brain also generate ketones themselves for use by neurons. You think we’d have that kind of set up in our brains if ketones weren’t useful to have around? If all we could do was burn glucose up there, what would be the point of even having localized ketone factories? Anyway, since the brain can use about 120 grams of glucose a day (PDF), that means you’d still need at least 30 grams of glucose while running on max ketones.

If you’re merely on a lower carb diet – staying under 150 grams per day or so – or eating medium chain triglycerides (coconut oil, MCT oil) to directly generate ketones, you’ll have access to ketones without being in full-blown ketosis, and your brain will be accessing some of them for energy. Take the story of Dr. Mary Newport, who lessened her husband’s Alzheimer’s symptoms simply by adding a couple tablespoons of coconut oil to his regular diet. The MCTs in the coconut oil were converted to ketones, which his brain began using. You’ll probably need more than 30 grams of glucose, but you won’t need the full 120 grams on a lower carb Primal way of eating (especially if you eat some coconut).

If you’re involved in strenuous exercise, your brain will be running primarily on lactate. Yep, lactate – that unwanted metabolic byproduct of muscle metabolism. During exercise, when the muscles are using up most of the available glucose to lift things and move a bunch of intelligent primate flesh through three dimensional space, and where inadequate oxygen (hence breathing hard) leads to incomplete glucose and pyruvate breakdown and increased lactate levels, the brain will draw upon lactate as a direct energy source. Not only that, but lactate appeared to make the brain run more efficiently, more snappily, and when both are available, the brain prefers lactate over glucose. Other research has found that the brain also prefers lactate in the hours and days immediately following a traumatic brain injury. I’m not sure how much glucose the brain requires when it’s accessing lactate, but it’s definitely fewer than 120 grams.

Of course, even when you need some glucose, that glucose needn’t necessarily come from dietary carbohydrate. It can famously come from gluconeogenesis, the process by which the liver converts amino acids into glucose. It can also come from glycerol, a byproduct of fat metabolism. In deep fasting situations, glycerol can contribute up to 21.6% of glucose production, with the rest presumably coming from gluconeogenesis. The glycerol can come from both dietary fat and adipose tissue (the authors of that glycerol fasting study even suggest that fasting burns body fat in order to provide glycerol for glucose production), while the amino acids can come from dietary protein (if you’re eating) or muscle (if you’re starving).

Overall, recent research into the metabolic demands of brain slices (“living” pieces of brains isolated and used for research) shows that incorporating other energy substrates – ketones, lactate, or even pyruvate – into the glucose solution improves oxidative metabolism and neuronal efficiency. Before you say “but this was in vitro, my brain’s not sliced up and submerged in a weird syrupy solution,” know that the whole point of the study was to better replicate the conditions of the kind of real, actual, living, thinking brains we find in human heads. The authors note that the glucose-only solution normally used to fuel brain slices in other studies is limited, because “in the intact brain, complex machinery exists that coordinates energy substrates delivery and adjusts energy substrate pool composition to the needs of neuronal energy metabolism.” In other words, glucose solution is an easy, dependable way to fuel brain slices, but it’s an incomplete representation of how brains work in heads. The authors conclude that “in slices as well as in vivo, the ability of glucose to maintain energy metabolism is limited and neuronal energy supply should be supported by other oxidative substrates.” 

So, a healthy, efficient brain is one that draws on several different fuels. A healthy, efficient brain is one that uses ketones (and perhaps lactate and other fuels) to spare some glucose. A complete reliance on glucose indicates an underachieving brain, a brain that could do so much better, a brain that could really use a coconut milk curry and some intense exercise every now and again. As far as we can tell, then, the absolute physiological minimum is 30 grams of glucose. I wish I could provide hard numbers for some of the other contexts beyond near carnivory (like basic 150 grams carbs Primal eating with coconut or maybe figuring out how to rely on lactate fueling), but the numbers don’t really matter in practice. What matters is that our brains don’t need the full 120 grams of glucose, especially if we’re following a Primal Blueprint eating plan.

I hope that helps.

Questions? Comments? Concerns? Leave them here. Thanks for reading!

TAGS:  dear mark, ketosis

Subscribe to the Newsletter

If you'd like to add an avatar to all of your comments click here!

Leave a Reply

153 Comments on "Dear Mark: How Much Glucose Does Your Brain Really Need?"

avatar

Sort by:   newest | oldest | most voted
Oliver
Oliver
4 years 2 months ago

First! Nice article 😀

Alexander
Alexander
4 years 2 months ago

Maybe it was answered before, I just haven’t seen it on the site, but I have a few related questions for Mark or anyone who knows:
Is 30g of glucose the same as 30g of carbohydrates, or is there a conversion?
The other question is, after an anaerobic workout, how can I figure out how much glucose is needed to refill glycogen stores (how do duration and intensity influence the amount)? Mark or anyone else, I’d appreciate an answer, sorry if this was discussed before and I missed it.

Primal Toad
4 years 2 months ago

There is fructose, glucose and sucrose. All are carbs. Sucrose is half fructose and half glucose.

Fructose does get metabolized differently. By the liver first.

But yes, 30 grams of glucose is 30 grams of carbs.

I have no idea on the second question but experimenting should give you a general idea.

Giuseppe
Giuseppe
4 years 2 months ago

I think Alexander meant “are 30g of glucose the same of 30g of fresh fruit”? In any case, that’s also my doubt. Are here we talking about pure glucose or edible food? I mean, are theme 30g of glucose, 30g of fresh fruit, 30g of honey?
I guess those are 30g of pure glucose, but how much fresh fruit are them? How to calculate it?

pam
pam
4 years 2 months ago

i believe it’s 30 g of glucose.

fruits also contain fructose & fiber.

regards,

matt
matt
4 years 2 months ago

No 30 grams of fruit are not equal to 30 grams of glucose, because the fruit is made up of more than just carbs..you have to look at the carbs themselves..a banana that weighs 200 grams may only have 70 grams of carbs. A good way to decide how much you need to recover after hard exercise is the 4 to 1 ratio..for carbs for every protein. so if you recover with 20 grams of protein then a banana or an Orange should be great.

Max Ungar
4 years 2 months ago

I would say it probably depends on the person. Possibly a little self experimentation is needed here.

Michelle
Michelle
4 years 2 months ago

Sometimes it is not about numbers but how you feel. If you eat something and still don’t feel ‘replenished’ then next time eat something more or different and see how you feel. Experiment of one!

joel
joel
4 years 2 months ago

My question is, how to go about finding that 30 grams of glucose, excuse my ignorance but are you propogating we actively go out and eat sugar, or would you say if you eating dark chocolate which has some sugar in it or say some alaskan smoked salmon which has say 2 percent sugar in it, this in actual fact could be benefitial rather than a hindurance?

What are good sources of glucose?

Peggy The Primal Parent
4 years 2 months ago

You get glucose from the breakdown of starches or some disaccharides. You don’t have to eat sugar, you can eat starch, like a sweet potato, yucca, unripe banana. Fruit has some glucose too but FYI fructose is not going to get converted and will be used for energy by other cells, not so much by the brain.

borntobelean
borntobelean
4 years 2 months ago

Nice info thanks Peggy

matt
matt
4 years 2 months ago

You can also eat bcaa’s these area agreat way to hinder sugar cravings that you have regularly. just have a scoop of this an hour before. but you liver will convert them to glucose for your brain…A lot of these questions are coming because people obviously didnt read the whole article…the answers are in there

JohnC
JohnC
4 years 2 months ago

You get sugar from nearly every single thing in the grocery store (look at the labels). Unless you cook absolutely everything yourself (and I mean everything, sauces, condiments etc) then you are probably getting a lot more sugars than you even realize.

Sugar is everywhere: deli meats including ham and turkey, many spice mixtures. People often don’t realize how prevalent it is because they don’t recognize all the forms of sugar that can be listed in the ingredients.

cancerclasses
4 years 2 months ago
Best source of glucose is from glycogen which your liver can easily make from your stored body fat, which spares your structural proteins & amino acids when, as a back up system & ONLY in the absence of stored fat reserves the body will engage gluconeogenesis to synthesize glucose from your structural proteins. Human physiological carbohydrate content is only around 1 percent of body mass, and it’s found in the stored liver & muscle glycogen and the glucose in your bloodstream which at homeostatic – A.M. fasting levels comprises only 1 teaspoon of sugar, 5 grams, out of the 1000… Read more »
Max Ungar
4 years 2 months ago

Genius! Can we see some sources? Thanks!

Ash Simmonds
4 years 2 months ago

>”The primary role of liver glycogen is to maintain normal blood glucose levels. When dietary carbohydrates are removed from the diet and blood glucose falls, glucagon signals the liver to break down its glycogen stores to glucose which is released into the bloodstream.”

~ “The Ketogenic Diet” by Lyle McDonald – http://books.google.se/books?id=JtCZBe-2XVIC&lpg=PA31&ots=dNISh1zQJz&hl=en&pg=PA30#v=onepage&q&f=false

MN_John
MN_John
4 years 2 months ago

Mark essentially states the same thing above about glucose, “It can famously come from gluconeogenesis, the process by which the liver converts amino acids into glucose.” People are getting confused here between need and supply, the brain needs glucose, but the supply does not have to be from carbohydrates, protein can be converted in to glucose when needed. For those on a very low carbs and/or intermittent fasting this is one less thing to worry about.

Daniel
Daniel
4 years 2 months ago

Makes sense; otherwise I’d be vegetable somehow using a computer (ketogenic diet).

Guillaume Ponce
Guillaume Ponce
4 years 2 months ago
> ONLY in the absence of stored fat reserves the body will engage gluconeogenesis to synthesize glucose from your structural proteins. Do you mean that anybody with even only 4% body fat (which is only achieved by bodybuilders on drugs) won’t do ANY gluconeogenesis? Do you mean that you won’t lose muscle tissue while fasting, even if you don’t exercise, provided you have some body fat? I don’t think that it’s what you actually meant, but the way you phrased it can lead to naive interpretations that are way too optimistic. Sorry guys, but VLC alone won’t allow you to… Read more »
einstein
einstein
4 years 2 months ago

disagree. body fat can not be turned into glucose. body fat can be used as fuel to convert proteins (fm food or muscle cells) into glucose. ketones are generated during this process which is called glukoneogenesis.

TokyoJarrett
4 years 2 months ago

I like how you put that. Very concise and logical.

Fred's Lettuce
Fred's Lettuce
4 years 2 months ago

Protein and fat are the “structure” of your body. Glycogen is the “fuel. What you guys are talking about is emptying the fuel tank by not eating carbs/fuel, then burning the structure for fuel (fat to glycogen). It’s great for losing fat weight, but in the long run _ eating fat only to build then burn is going to kill your kidneys. For the life of me I cant figure out how you guys justify a “starvation” diet as healthy. Oh well, if even one reads this and asks the question …

Lewis
Lewis
4 years 2 months ago
No, he doesn’t mean that, Joel. He means that physiologically you need some glucose. However, the source doesn’t have to be dietary carbohydrate – let alone glucose itself. If it had to be, historic populations — e.g., people living in the Arctic, or people going without food while searching for it — would be in a bad way. Have a look again at the paragraph in the post beginning: “Of course, even when you need some glucose, that glucose needn’t necessarily come from dietary carbohydrate. It can famously come from gluconeogenesis, the process by which the liver converts amino acids… Read more »
Wafaa
Wafaa
4 years 2 months ago

Carbohydrate will turn to glucose through digestion. If you eat a lettuce, an apple, a sweet potato, or any kind of vegetable or fruit you’ll get your glucose. You don’t need to ingest glucose straight up. Even sugar is not pure glucose, it’s sucrose which is a bonded glucose and fructose.

Shary
Shary
4 years 2 months ago

I don’t see this as a concern. Eating a paleo diet, tweaked according to however your body functions best, should be sufficient. Your body will automatically see that your brain gets what it needs. That’s its job! You don’t need to micromanage the situation by adding in various sugars, and in fact, you’ll be better off if you don’t.

Marc
Marc
4 years 2 months ago

I generally just get by eating plenty of vegetables. 30g goes pretty darn quickly, although I’d have to look how much of that is in soluble fiber. Not really sure how that gets metabolized (if it does).

Harry Mossman
4 years 2 months ago

My doctor says my “liver enzymes are too high.” I’m trying to figure out how fasting, low carbs (50-70/day) and anti-oxidant organic, pastured, free-range food affect this. I have cut back to mostly eating from about 11 am to 7 pm. No numbers yet. Now I wonder how the conversion of fat to ketones plays into the equation. It’s all very complicated and I don’t think anyone has all the answers.

Primal Toad
4 years 2 months ago

We will never have all the answers to complex questions like these. We are complex beings.

Continue to experiment on yourself.

Harry Mossman
4 years 2 months ago

Thanks. True. But in this case, I honestly feel that we are a long way from having most of the answers.

Paul
Paul
4 years 2 months ago

My wife’s high liver enzymes led us to the Primal lifestyle. When all was said and done it was gluten that was the culprit – something a lot of doctor’s don’t know enough to test for, though that is changing…

David Cole
David Cole
4 years 2 months ago
Liver enzymes are too high for what? I just did some reading on this and it seems that ketosis has been known to produce high liver enzymes. I also read that high liver enzymes do not necessary cause liver disease. I doubt you have fatty liver disease or liver problems if you have been Primal for any length of time as this way of eating improves liver health (as compared to SAD diet) In the context of a diet such as yours that is low in fructose I think it’s safe to say it’s not anything to worry about. At… Read more »
Harry Mossman
4 years 2 months ago

Thanks. Per a recent ultra-sound, I do not have fatty liver. The doc is wonderful in many ways but very CW. She told me to stop Metformin and ALL supplements because they were “harming my liver.” I tried to explain that choline, dessicated liver and turmeric, for example, were good for the liver. She normally listens well but not to that. I now take them with meals (and only when I don’t get them from food for a while.)

I rarely go into ketosis and have been off gluten for many years.

Heather
Heather
4 years 2 months ago

Why were you on Metformin? Since going primal, it was the second drug I ditched, it closely followed the acid reflux drugs? If you insulin sensitivity is ok and your blood sugar under control, Metformin would be surplus to requirements anyway. I would have another test in a little while, remember the blood is a moving feast and the test is just a snapshot.
Cheers

Harry Mossman
4 years 2 months ago
I was on Metformin because my glucose was still too high (~120). From my reading, it is by far the best drug for diabetes. I am not, and have no intention of ever being, strict primal. After being taken off Metformin (I refused to take the other drug the doc wanted me to take), I increased my activity some, I watch my carbs a bit more, and I want to say do IF but I eat small amounts of food (like 5 almonds) between meals. I know that people reading this who fast are getting red in the face, their… Read more »
Adam
Adam
4 years 2 months ago

I think the 5 almonds is fine – just like anything in the human body, i think fed vs. fasted is not an “on-off” switch so much as a gradient of hormonal responses (like a light switch with a dimmer). 5 almonds is unlikely to take you out of the fasted state, but someone can feel free to correct me if I’m wrong.

Heather
Heather
4 years 2 months ago

Ahh ok, yes I found I tolerated Metformin well, but I have been off it now for about 6 months. Good luck with the measures you are taking, with an enquiring mind I am sure you will be fine.

Lee
Lee
19 days 23 hours ago

Coffee is supposed to be good for the liver, scientist dont know why yet as coffee has 100s of different compounds in it, could be due to the antioxident content although decaf coffee doesn’t have the same effect on the liver as normal coffee so its much more than that. But its worth looking into

Beklet
Beklet
4 years 2 months ago

So, am I right in thinking that actually, I don’t need to eat ANY carbs at all, and my liver will make all the glucose my brain needs from the amino acids in the protein I eat?

Is that also the case if I am doing a heavy weights workout, or would I need to eat some carbs because my body wouldn’t be able to produce glucose fast enough?

Ash Simmonds
4 years 2 months ago

Yes, carbs are unnecessary, in a fat-adapted person the body will source it’s minute glucose requirements from glycerol and glycogen.

It takes several weeks/months to properly fat-adapt, in that time you’ll have reduced abilities as far as high power stuff goes, but afterwards will be fine. The problem is actually being able to remain VLC for such a long period of time in our culture.

Beklet
Beklet
4 years 2 months ago

Excellent…..yeah, I’m gearing up for a month working in an airport, can only buy food and drink from within the terminal, and of the three or four places open to me at the time, none are primal…it’s going to be salads for me for a month 😀

But good to know, I’m a terrible sugar junkie, easier to eat none than any….

MN_John
MN_John
4 years 2 months ago

I’ve found when I’m in solid ketosis that my rapid energy supply runs out very quickly, so no marathons. But at a slow paced resistance routine I can go all day (with intermittent breaks to let my energy supply catch up). This works well with a Primal routine because we aren’t suppose to be running for hours at a time, but we should be able to walk with a 50lb hunk of animal meat strapped to our back.

Shary
Shary
4 years 2 months ago

If you’re referring to grains and sugars, NO, you don’t need them at all. If you’re including vegetables and fruits, which are also carbs, YES, you do need them for the nutrients they contain, but only if you want to remain in good health all your life.

Heather
Heather
4 years 2 months ago

And if you were to eat offal and drink bone broth and eat fermented foods you wouldn’t need vegetables or fruit. Leafy greens? – yes. Veggies/fruit? – optional. Although they do make great vessels for my fats!

einstein
einstein
4 years 2 months ago

if you work out heavily, you will need some carbs in your food. else your performance will be affected negatively. why would you want to avoid carbs if you do heavy workouts? enjoy them, after all you deserve them for all the effort 🙂

Patrice
4 years 2 months ago

Great research Mark, I always end up with at least 6 new tabs open with follow on reading when I read your articles!

I always find a bit of IF (16 hrs usually), then exercise… and my brain seems to be supercharged! Not sure if that’s generated by gluconeogenesis but it certainly feels good.

Damien Gray
Damien Gray
4 years 2 months ago

It is key to note that you do not need to eat those 30g of glucose. Your body is perfectly capable of generating it from protein using gluconeogenesis. You can thrive on no dietary carbohydrates.

trackback

[…] out more about how the brain uses glucose, ketones and lactates in “How much glucose does your brain really need” by Mark Sisson. Share this:TwitterFacebookLike this:LikeBe the first to like this. This […]

gibson girl
gibson girl
4 years 2 months ago

I really enjoyed this article, Mark!

State-Smashin' Caveman
State-Smashin' Caveman
4 years 2 months ago

This was actually pretty interesting.

Peggy The Primal Parent
4 years 2 months ago
Nice topic! The perfect Health Diet website has some interesting posts on the topic too for anyone looking for more. I just wanted to add that it is useful for the brain to have the ability to use ketones. It would be pretty horrible if there were no back up plan in place. But that doesn’t mean that the brain is better off using them. Having done zero-carb myself for years on and off, I’ve wondered if there is an ideal. I’ve never felt tired or distracted or slow on ketones. Honestly, I can’t tell the difference as far as… Read more »
Primal Toad
4 years 2 months ago
Our brains may not need all that glucose from foods but that does not mean that are brain can’t function better with more carbs from sources like potatoes, sweet potatoes, other root veggies and fruit. The intuit have been selectively pressured to eat the way they do. Thus they are able to thrive generation after generation. If I decided to live with the Eskimos then I may struggle and not survive. I don’t know for sure but this is my theory. We all need to continue to experiment. Eat whole, real food and don’t worry about macronutrients. Just eat the… Read more »
cancerclasses
4 years 2 months ago

Minimum carbohydrate is your body’s NATURAL STATE, and it’s UN-natural state is carbohydrate overload. Everyone has it backwards. http://goo.gl/EQpU0

cancerclasses
4 years 2 months ago
Google ‘sugar impairs brain function’. From Wikipedia re Vilhjalmur Stefansson: “Stefansson is also a figure of considerable interest in dietary circles, especially those with an interest in very low-carbohydrate diets. Stefansson documented the fact that the Inuit diet consisted of about 90% meat and fish. Inuit would often go 6 to 9 months a year eating nothing but meat and fish, essentially a no-carbohydrate diet. He found that he and his fellow European-descent explorers were also perfectly healthy on such a diet. When medical authorities questioned him on this, he and a fellow explorer agreed to undertake a study under… Read more »
cancerclasses
4 years 2 months ago
From Wikipedia re No-carbohydrate Diet: “A no-carbohydrate diet is ketogenic, which means it causes the body to go into a state of ketosis (converting dietary fat and body fat into ketone bodies and using them to fuel the entire body and up to 95% of the brain. The remaining 5% still runs on glucose which is adequately supplied by converting dietary protein via gluconeogenesis or by converting glycerol from the breakdown of fat).” From Wikipedia re Lactic Acid, Brain Metabolism: “Although glucose is usually assumed to be the main energy source for living tissues, there are some indications that it… Read more »
pbo
4 years 2 months ago

Agree 100%! Just eat real food, and let the macros fall where they may. If you find yourself needing more energy you can start to play with adjusting.

BJML
BJML
4 years 2 months ago

Here’s a link to the first part of a three part article on Stefansson:
http://www.biblelife.org/stefansson1.htm
The link to the next article will be at the end of each part. Enjoy!

Yvette
Yvette
4 years 2 months ago

I agree. But, I’ve done the plain potato thing before and it does the trick for a few hours but not long enough to last me till dinnertime. I think I’d rather eat leafy greens with butter if I can’t get to tasty meat.

fritzy
fritzy
4 years 2 months ago
Toad, I agree with the notion of self experimentation, but to say “don’t worry about macronutrients” is ill advised for many and is a statement that you can personally make as a result of your own self-experimentation. You are young, lean and likely to have good insulin sensitivity. This statement does not apply to everyone. Many people have metabolisms that are so “jacked-up,” they will never be able to eat anything but a ketogenic diet if they wish to remain healthy. For some, macronutrients do, and always will matter a great deal, even on a “whole food diet.” Carbohydrates are… Read more »
Primal Toad
4 years 2 months ago

Sure 🙂

Joy Beer
Joy Beer
4 years 2 months ago
In season 1, episode 3 of “Medicine Men Go Wild,” one of the twin brothers (both doctors from the UK) lived on the native diet of frozen fish, walrus blubber and meat, and the other brother on the shop foods. The native-diet eating brother experienced a 30% improvement in his cholesterol results and the shop-foods brother a 30% decline. And the shop-foods bro felt like garbage. The native-foods brother grew to love fermented walrus fat, according to their own web site. I’d say that the northern European was on his way to adapting very nicely to that diet. That show’s… Read more »
Joy Beer
Joy Beer
4 years 2 months ago

I forgot to mention that they were staying with Eskimos from Siberia, to see why and how they have such low rates of heart disease.

Max Ungar
4 years 2 months ago

I think its key to note from this article that our bodies produce its own glucose for the brain. But just like the Primal Toad said, it is important to keep self experimenting in terms of how much, what kind, and when we take in extra carbs. I think this might be one of the Primal food guidlines that may be different for everyone.

Groktimus Primal
4 years 2 months ago

People always try to over simplify things. If we did not have fail safe systems we would not be here today. Society needs to think beyond the sound bite.

Tenny
Tenny
4 years 2 months ago

fascinating!

Stormi
Stormi
4 years 2 months ago

Very interesting article as always!

Susanne
Susanne
4 years 2 months ago

What are the dietary implications for those of us who make our livings by thinking? As a research scientist I need to have my brain running on all 12 cylinders consistently. I can’t make do with 6 or 8. Any ideas?

cancerclasses
4 years 2 months ago

Dave Asprey at bulletproofexec claims 12 I.Q. point rise from supplemental creatine, and a total of 40 points by incorporating all of his brain hacks. Google ‘bulletproofexec, top 6 bio hacks’.

BillP
BillP
4 years 2 months ago

You’ve got 12 cylinders??!! I am so jealous…

Marissa
4 years 2 months ago

great article…and i can relate to family & friends worrying about my style of eating. the best argument to this is having them witness me at my very best (mentally & physically) all.the.time!

drea
drea
4 years 2 months ago

The glucose from carb-dense foods may be unnecessary but the micronutrients fruits and vegetables provide are absolutely necessary! I suppose you could supplement all those things in but would be incredibly meticulous and, I suspect, downright dangerous. It’s an interesting conclusion, though, I do admit, as long as people don’t start getting extreme (who would do such a thing?) and try cutting out important sources of micronutrients because they forget and focus so heavily on ridding themselves of ‘unnecessary’ carbs.

Sofie
Sofie
4 years 2 months ago

Or you could eat the animals who ate those nutrients, and be perfectly healthy. http://www.biblelife.org/stefansson1.htm

Peggy Holloway
Peggy Holloway
4 years 2 months ago

We need a like button! I so agree!

Christine Mattice
4 years 2 months ago

With today’s unhealthy junk food diets, I’m afraid that most of our brains have too much glucose! Thanks for the great article!

pbo
4 years 2 months ago

Honestly glucose is the least of your problems from the SAD. At least glucose is belongs in your body… just think of all the other crap that is going into your body when eat some food engineer’s “perfectly designed” hyper-palatable product in box. No thank you, I’ll stick to meat/veggies/fruit/tubers please.

Jay
Jay
4 years 2 months ago
Mark this article is perfect timing. I just started a very low carb diet on July 1. I am coming from a low carb diet so it won’t be hard. I just wanted to start burning Ketones again for two reasons. First, my father and grandmother both had alzheimers disease. I have read several reports that this disease may be due to a virus or bacteria. I hope that switching to Ketones every so often will slow down the growth or maybe even get rid them. I am willing to experiment to find out! My plan is to burn Ketones… Read more »
Peggy Holloway
Peggy Holloway
4 years 2 months ago

You won’t cramp if you take SloMag regularly.

Peggy Holloway
Peggy Holloway
4 years 2 months ago

And “carbing up” is not a good idea. Why not just stay in ketosis? You won’t burn ketones if you resume eating carbs. You’ll go back to glycogen burning and won’t be able to access fat stores for energy. Have you read “The Art and Science of Low-Carbohydrate Performance?”

borntobelean
borntobelean
4 years 2 months ago

I agree peggy I’ve been paleo for 4 months now and went camping over the weekend and fell off the so called wagon and felt like absolute garbage and i’m just now starting to feel better. Once I started on what I consider junk carbs I couldn’t stop. Then I got a headache and cramping and I was done. So carbing up wouldn’t work for me.

doghug
doghug
4 years 2 months ago

good post 🙂

Peggy Holloway
Peggy Holloway
4 years 2 months ago
I don’t believe one needs 30 g/day of dietary carbohydrate – a portion of protein will metabolize as glucose and the liver, as you say, will produce glucose. I eat very little carbohydrate in the form of green veggies (no starches) and nuts. I estimate my carb content to be around 20 g/day. Recently, I did two long distance bike trips where there were not even green veggies or nuts available, so I lived on cheeseburger patties, eggs, and ribeye steak. I was fueled more than adequately by ketones and had not problem with brain function! Actually, I consider a… Read more »
BillP
BillP
4 years 2 months ago

+1
I love anecdotes like this one.

trackback

[…] Mark dropping some more knowledge about the brain and how much glucose it needs http://www.marksdailyapple.com/how-much-glucose-does-your-brain-really-need/ […]

trackback

[…] Dear Mark: How Much Glucose Does Your Brain Really Need? Mark’s Daily Apple Some OHWLs are always a good time […]

Dan
Dan
4 years 2 months ago

If dietary carbs are unimportant, why did we evolve with such powerful taste buds for sugar?

fritzy
fritzy
4 years 2 months ago
I don’t think anyone said they were unimportant–just unnecessary. Our ancestors would have required a variety of metabolic pathways to become the species we are today. We (as a species) have had to tough out at least two ice ages (when carbohydrates would have been in low supply,) as well as environments that may not have supported a great deal of animal life for periods of time. The members of the species that could thrive off a wide variety of foods would fare best. Certainly, carbohydrates would have been available in large abundance at times–at those times, they would serve… Read more »
Dan
Dan
4 years 2 months ago

At least one comment above, and many other comments on other paleo boards, claim humans do not need dietary carbs. Also, i often read people confusing Keto with paleo.

No hunter-gatherer group was consistently zero-carb. Even Greenland native peoples at tubers when they could.

Low carb paleo/primal, great.

Zero carb, I am extremely skeptical.

Sofie
Sofie
4 years 2 months ago

Also, sweet taste buds can indirectly taste fat.

BillP
BillP
4 years 2 months ago

Possibly the only major source of sweet stuff was fruit & honey. Very nice once-in-a-while or seasonal foods that could help one build fat, to help immensely over the leaner times of winter. So, there had to be a big (taste) incentive to either gorge on fruit in autumn, or to fight your way past the stinging bees to get the honey.

andre Chimene
4 years 2 months ago
Because we are stupid! Don’t listen to your body…it will tell you to do cocaine and too much booze and take way too many adrenaline boosting risks and unprotected sex and cheat on your taxes and stay in Hawaii and forget your work and smoke too much dope and masturbate on the computer instead of sex with your long time partner and bitch slap that bastard who just cut you off in traffic even though he drives a jacked up pick up with a full gun rack and if it feels good do it and so it goes…my body told… Read more »
Jim Ulaszek
Jim Ulaszek
3 years 8 months ago

Hilarious! Thanks for that.

Mark
Mark
4 years 2 months ago

Guys,

Thank you for sharing your insights and knowledge on the subject.

I’ve recently gone primal- and that has necessarily lowered my overall calorie intake. It would appear that this has triggered a bout of acidity that keeps making me form saliva, especially when i work out hard. I deadlift in the range of 300 pounds and squat close to the same, and one of the downsides is that it looks quite disgusting, wiping ths spittle off of my face in the gym constantly.

any solutions for me- i would be extremely grateful.

Shannon
Shannon
4 years 2 months ago

I’ve been trying to slowing move my family over to a more Primal diet. I’ve noticed that Coconut has many benifits, and was wondering if there was anything else out there that could take it’s place? My Husband and Daughter are allergic to coconut.

BillP
BillP
4 years 2 months ago

Are they allergic to the oil or to the meat or the milk? Or all?

Shannon
Shannon
4 years 2 months ago

I tried coconut oil in a regularly used recipe. With the first bite my daughter’s face, and throat started swelling, she broke out in a rash and couldn’t stop itching. I didn’t want to try anything else. Any idea’s?

Per Wikholm
4 years 2 months ago

Actually, here in Sweden the guy who holds all 18 swedish records in memory contests, Mattias Ribbing has taken them all on al Low Carb High Fat (LCHF)diet. He can memorize the exact order of cards in 10 decks of cards.

Here is moore on Ribbing (Google tranlsated from Kostdoktorn/Dietdoctor):

http://translate.google.se/translate?sl=sv&tl=en&js=n&prev=_t&hl=sv&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fwww.kostdoktorn.se%2Fsveriges-basta-minne-pa-lchf%2F&act=url

trackback

[…] We now know that the oft-repeated “your brain only runs on glucose!” is wrong. I’ve mentioned it before, and anyone who’s taken the time to get fat-adapted on a low-carb Primal eating plan intuitively knows that your brain doesn’t need piles of glucose to work, because, well, they’re using their brain to read th… Mark’s Daily Apple […]

park chi
park chi
4 years 2 months ago

Ray PEAT??

dana
dana
4 years 2 months ago

came across this link while studying dementia this morning…worth a watch:

http://www.youtube.com/watch?v=Ls6VE3ZagUI&feature=youtu.be

trackback
4 years 2 months ago

[…] How Much Glucose Does Your Brain Really Need? […]

trackback

[…] insulin resistance, which sound like negatives but are actually necessary to spare what little glucose exists for use in the brain. On the other hand, a well-constructed, lower-carb (but not full-blown ketogenic) Primal way of […]

trackback

[…] how much glucose does your brain need? recipe: […]

trackback

[…] the word “paleo” gets made fun of…   Halil Mutlu and Kaki Kakhiasvili Training   How Much Glucose Does Your Brain Really Need? […]

trackback

[…] insulin resistance, which sound like negatives but are actually necessary to spare what little glucose exists for use in the brain. On the other hand, a well-constructed, lower-carb (but not full-blown ketogenic) Primal way of […]

Dave
Dave
4 years 2 months ago
You know, this makes perfect sense to me – especially the part about the brain running on lactate, as well as other “alternative” fuel sources. “the brain will draw upon lactate as a direct energy source. Not only that, but lactate appeared to make the brain run more efficiently, more snappily, and when both are available, the brain prefers lactate over glucose. Other research has found that the brain also prefers lactate in the hours and days immediately following a traumatic brain injury.” Doesn’t it make perfect sense? So through evolution/development, the body learned to prioritize the brain – and… Read more »
trackback
4 years 2 months ago

[…] Dear Mark: How Much Glucose Does Your Brain Really Need? […]

trackback

[…] but if you limit your fructose intake, you’ll be limiting your glucose intake as well. Which is okay. I also do not think that fruit is the devil, I simply think we should be aware of what’s in […]

Marzo
Marzo
4 years 1 month ago

Isn’t Lactic Acid only produced from Glucose?

Lex
Lex
1 year 6 months ago

Lactic acid is produced in the absence of oxygen from glucose. It builds up during exercise, because as you try to adjust your breathing there is less and less oxygen available from taxation.

Ann
Ann
4 years 24 days ago

Just what I was looking for – for when my husband’s medical friends say that that brain can run on ketones but not well. (I feel this is said ‘smugly’ to myself, a mere mortal without a medical degree, or is that a false perception generated by my ketogenic brain ?)

fabiolabutoyi
4 years 4 days ago

how would you know when you need a glucose
and what is a glucose.how doe it work.

trackback
3 years 11 months ago

[…] BLOG: how much glucose does your brain really need Share this:FacebookTwitterEmailLike this:LikeBe the first to like […]

Leo-Brown
Leo-Brown
3 years 9 months ago

i don’t know what is wrong with my brain please can somone help me out. when ever i study my books i easily foget what i have read. please do i need glucose to cure this forgetful act?

Ben
Ben
3 years 8 months ago
Love your website! By educating me you have inproved my diet and because im eating better the positive effects tumble over into many aspects of my life. Im only 23 but going by my curent health status I expect to live a really long healthy and happy life which you will have contributed to. One final thing I want to add is that I have some mental issues which I obviously don’t usually broadcast but had to say that this way of eating has really helped me control them grately! I hope you sleep easy at night knowing you have… Read more »
trackback

[…] brain runs on glucose — sugar, essentially, but converted fat, ideally— but its easier to think of it like a smart […]

trackback

[…] much glucose does the brain really need? @Mark_Sisson answers: marksdailyapple.com/how-much-gluco… #brain #health […]

Tigara
Tigara
3 years 5 months ago

So obviously, 1 g glucose = 1 g carbs. But does 1 g carbs = 1 g glucose? How many carbs should I be eating to get enoigh glucose?

Laura
Laura
3 years 5 months ago

Wow this is very interesting.My daughter had just been diagnosed with glut1 ds.Glucose transmitter deficiancy syndrome. Very rare and it means her body doesnt absorb glucose correctly and in turn this has given her epilepsy. We are starting the ketogenic diet on tuesday. Thanks for this interesting read.

trackback
[…] By the way, if you’re exercising in a state of ketosis, you don’t need to worry about neural fatigue from your brain running out of fuel. Once you begin exercising, your brain will draw upon lactic acid as a source of energy (your brain actually prefers to burn lactic acid and ketones more than glucose!), along with fats, glucose derived from amino acids (gluconeogenesis), glucose derived from slow-release starches, and glucose derived from trace amounts of sports supplements – all of which you’ll learn about later in this chapter. If you want to learn more about the minimum amount of  carbohydrates your brain… Read more »
wpDiscuz