When you are on a ketogenic diet, the mitochondria in your cells — the parts of the cells that produce energy — actually switch from primarily using sugar for fuel to primarily using fat for fuel. They use fat mostly in a form called ketone bodies (or, commonly, ketones), thus a ketogenic diet.
(See Keto-adaptation: what it is and how to adjust for more on this process of switching fuels.)
Sugar-based living (from a diet with more than about 5% calories from carbohydrate)
When you are using the sugar-based system, all of the cells in your body constantly take sugar out of your bloodstream. It's hard for your body to keep up, and you need to frequently refuel by eating carbohydrate-containing food.
Getting sugar out of the carbohydrates that you eat is a blunt tool. Unless you eat in a trickling stream, you will consume more sugar than is safe to hold in the bloodstream at once. That sugar has to be quickly removed, because high blood sugar damages your cells. So a flood of insulin comes in to initiate the process of sugar removal. There is some limited storage space in the liver, but when that is full, the rest basically gets stored as fat.
Soon however, the job is done. Your blood sugar is back in a safe range. Your body cells are still demanding sugar, though, and your blood sugar starts to drop too low. Your liver can release some sugar back into the bloodstream, but not fast enough to keep up with demand, so you get tired and hungry, and the process starts all over.
- People on carbohydrate-based diets typically have to "snack" every couple of hours.
- Endurance athletes have to stop and eat sugar just to get through their events.
On a sugar-based metabolism, you swing between too little blood sugar and too much, and you have to constantly adjust it "manually" by eating.
On the other hand, when you are using the fat/ketone-based system, there is relatively little demand on your blood sugar. There are only a few kinds of cells that don't have the ability to use ketones (or fat) for fuel, and have to use sugar. That amount can easily be supplied by the liver, which actually manufactures sugar out of protein on demand in response to changes in blood sugar.
The liver can do this at a rate that is more than adequate for normal energy requirements, when the cells that can use fat/ketones are doing so, and thus not putting extra demand on blood sugar. Your body makes significant ketones only when sugar levels are consistently low.
- It is not uncommon for ketogenic adults to comfortably eat one meal a day. Even my children, when they are ketogenic, can go for several hours at a time without eating.
- Endurance athletes on ketogenic diets don't "hit the wall". They have the ability to tap into fat stores for fuel; a supply that could last even a lean person for weeks.
On a fat/ketone-based metabolism, demand on sugar from the blood is gentle, and your liver refills it smoothly on demand as it is used, keeping it remarkably steady.
An argument for ketogenic metabolism as the default human state
Think about the role of the liver here. When you are not consuming sugar in food (from carbohydrates), your liver orchestrates fuel management precisely.
The liver makes ketones out of fat, thereby supplying almost all tissues with all the energy they need. At the same time, it makes a moderate amount of sugar out of protein. That sugar is stored right in the liver in the form of glycogen. Not much is stored, but it is plenty for the purposes of keeping blood sugar steady, because the blood sugar is depleted slowly: only a few tissues draw sugar from the blood. The rest are using fat or ketones.
This system is efficient and effective.
By contrast, on a carbohydrate-based diet, the storage capacity of the liver overflows. The excess sugar can be stored as fat, but that fat is not used efficiently as fuel. For fat to be used efficiently as fuel, the liver would have to be turning it into ketones at a high rate . But ketones aren't produced much in a high sugar condition. It takes several days of low sugar intake to start producing significant ketones.
Considering how well the liver manages energy when you don't eat carbohydrates, and the disruption caused to this system by eating them, I would suggest:
The conditions under which the liver delivers optimal fuel on demand may be the conditions under which it evolved.
|||As pointed out by Valerie and Ash in the comments, and by Carol Loffelmann on Twitter, fat remains an important fuel in its own right, increasingly so after keto-adaptation. I oversimplified here, but the point about efficient fat/ketone-based metabolism under low sugar conditions still stands.|
Consider a popular alternative explanation:
Noticing that excess sugar can be stored as fat, and yet knowing that excess fat storage is not healthy in humans, some people have argued that excess fat storage in humans represents an adaptation gone awry:
The thrifty gene hypothesis supposes that we used to go through periods of feast and famine, getting fat, and then using it up. People who were well adapted got fat easily, and thus survived the famines better. Here and now, where famines are rare, those people would simply get fatter and fatter.
There are at least two problems with this idea. First, the evidence doesn't seem to bear it: famines may not have been particularly common in Paleolithic times, they don't appear to have occured at all in some populations that we know later developed obesity on modern diets, and modern hunter-gathers don't get fat in times of plenty. Second, even if this were essentially correct, that would mean that humans were adapted to go through regular periods of using up the fat. In other words, it would mean humans were adapted to regular periods of ketogenic metabolism! So, at best, this theory supports ketogenic metabolism being a regular part of life in some kind of alternation with carbohydrate-based metabolism.
There are animals that use this kind of strategy. Those animals hibernate. Humans can't hibernate. Even very fat humans need some level of protein to survive, to make into sugar for the few tissues that need it. If they don't get it, they will start tearing down essential muscle tissues such as heart, and they will die.
"The conditions under which the liver delivers optimal fuel on demand may be the conditions under which it evolved."ReplyDelete
I've been thinking the same thing.
you state a few times that most of the energy used by cells under a ketogenic diet comes from ketones. I was under the impression that fatty acids provided most of the energy, with only some of them being turned into ketones by the liver. Do you have any reference on that?
Good point. I'll fix that. I was specifically thinking of the brain when I wrote it. However, the basic argument still stands: that efficient use of fat/ketones doesn't kick in under a condition of high sugar intake.Delete
This article, by the way, was not meant to be a scientific treatise, the way I do on ketotic.org. It is just a gist argument.Delete
Cunningham's Law in action. :DDelete
After weeks (months) of an uninterrupted ketotic state most of the body down-regulates ketone usage and becomes more efficient at higher fat usage, with ketones apparently mostly spared for the brain, CNS, and possibly heart. There's a graph of this I've drawn in my head which I should scribble down sometime.ReplyDelete
I don't have a single concise source that I can point to, it's just my elevator pitch take from the variety of literature ranging from old-school epilepsy diets, bodybuilder cutting diets, mostly carnivorous hunter/gatherers (you know, the ones "not in ketosis"), modern keto/paleo stuff, "default" fasting metabolism, and starvation. It's covered pretty approachably by Lyle McDonald, Phinney/Volek, Cahill/Veech, and various current/recent prominent bloggers.
Nice post, I wonder what state other primates are in.ReplyDelete
Would ketosis as a primary state for hominids have been more important for more evolved hominids more able hunters, erectus? Personally I suspect that like our cousins the chimps early hominids were probably quite capable hunters.
I'm not sure if I would quite see it like that. Modern humans might have been big game hunters, or on a more coastally-derived diet, or indeed on a high carb and high tobacco diet (Kitavans), but really, in the scheme of things it is all rather recent. In the long run, despite the constant talk about starches and tubers, aren't we really just evolved from a line of predominantly frugivores? And wouldn't the way our metabolism deals with carbs simply be a preserved adaptation? Not sure what exactly is optimal, but there appear to be 3 ways that work well (i.e., unimpaired glucose regulation): carb restriction, IF, or calorie restriction (or a combination of those). None of those options are even remotely approached under the standard western diet.ReplyDelete
As Richard Feinman has stated, the reaction coming upon a patch of berries (or honey) wouldn't have been moderation. Prior to the agricultural 'revolution' I wouldn't see that as sub-optimal. It might be, but I haven't seen much evidence for that. Of course the agricultural 'revolution', and even more so our modern environment, has shown this preserved adaptation to be a profound handicap. But what is default and what is optimal? For many of us, living in the modern world with our mitochondrial and metabolic disease (pre-diabetes or worse), cutting carbs virtually entirely is both most practical and optimal, albeit not necessarily evolutionary default.
Anyway, I love your blog. There are so few keto-friendly paleo blogs left, it would be depressing if I weren't on a ketogenic diet.
"So, at best, this theory supports ketogenic metabolism being a regular part of life in some kind of alternation with carbohydrate-based metabolism."Delete
Sorry, I see you sort of stated my position already. I didn't read very well! Yes, I don't buy the thrifty gene hyp. I believe most humans must have had plenty during the last several hundred thousand years, and plenty of meat and fat at that. That is, prior to agriculture. It was Cohen's "The Food Crisis in Prehistory" that made me realise that agiculture was a necessity and last resort, not an invention. An answer to overpopulation. And so in my view a relatively harmless preserved adaptation became a liability.
I think it's important to remember that peripheral cells can use FFA as a direct fuel via Beta oxidation. One can be a fat burner without going into ketosis.
I do think the liver is the sensor of available fuels, supplying/controlling release of substrate and production of alternatives (ketones/lactate clearance rate/Cori cycle) dependent on changing whole body requirements.
Plus the liver tries to protect the body against glucose toxicity (glycation). Glucose flows through it as it is absorbed, this is in contrast to lipids (chylomicrons).
Excellent points. Thank you!Delete
I have done many water-only fasts over the past twenty years. My longest was 26 days. I have resorted to water-only fasting from time to time because all the foods I was eating (Vegan plant-based diet) made me feel terrible and I just could not figure out what to eat. The only time I felt good was when I ate nothing at all, and I often joked that if I did not have to eat to live everything would be fine. I came across meat-based and Ketogenic diet information here and there throughout the years, but I had a hard time letting go of my ideology about veganism, and the versions I read about always seemed prohibitively expensive for my financial resources. However, there has been an explosion of information about LCHF eating in recent years, and I feel like I am now coming full circle. Find blogs like yours, Amber, is making all the difference for me being able to pursue this type of diet. I think an all meat diet may be the answer I have been seeking about how to feel as good as I feel on a fast without actually having to fast. The benefits I experience during fasting are likely due in part to ketosis, but also to simply not putting any plant food poisons into my body. I am so eager to begin a meat-only version of the Ketogenic diet a try.ReplyDelete
This comment has been removed by the author.ReplyDelete
You're the best to provide people with a stupendous probability, I am continually scanning on the web for articles that can help me.ReplyDelete
gria2 elisa kit
How beautifully all the feelings have been conveyed through writing.ReplyDelete
lose your belly diet
Some of the best-tasting, most fulfilling foods are part of this plan, including lean meats like beef and chicken best keto diet drinksReplyDelete
I would have to say a low ketogenic diet foods! It is a fast way to lose some weight! I am on it and am very pleased with the results I only wanted to lose ten pounds and I lost more in about a 21/2 week period and you can definitely tell! For low carb you start out by eating 20g of carbs a day for 2 weeks. By just doing this it will shock your body and after three days you will be in a state of contoses. The state of contoses is where your body will run off the 20g of carbs and the already exsisting fat/carbs and burn them away! After 2 weeks of 20g you should go to 30g for another 2 weeks, 40g-2 weeks,50g 2 weeks.. Then drop back down to 20. It is a quick way I lost.I suggest you ketogenic diet foods through this you get more results about the ketogenic diet .ReplyDelete
Thanks for the blog post buddy! Keep them coming... helloketodiet.comReplyDelete
Totally awesome posting! Loads of valuable data and motivation, both of which we all need!Relay welcome your work. https://www.thenaturalremediesfordiabetes.com/diabetic-shoes-for-women/ReplyDelete
For weight loss and strictly weight loss, there is no "American diet." The "American diet" is the one you can stick to. For some people this will be to simply eat less without changing the makeup of the foods they eat, for others it may be low carbohydrate, low fat, etc. As a rule of thumb, though, radical dietary change tends to fail because it is too hard to stick to. Portion control works for some people, as does cutting out certain types of "food" - like calorie-containing beverages or foods high in added sugar.ReplyDelete
When you have all the ATP you need to meet your energy requirements, the body converts the excess blood sugar into fatty acids low carb 30 minute mealsReplyDelete
The Atkins Diet is likely the most renowned low carb diet. Things being what they are, what precisely is a low carb diet?moreReplyDelete
Review the Chinese axiom. The two diets will help you to get thinner. Just a single diet, notwithstanding, will show you how to act naturally dependent after your experience is finished. dietsReplyDelete
short and simple health article which defines everything that everyone love to read and implement.ReplyDelete
Review – Fat Loss Code – Is the Course of Shawn Stevensons Reliable?
i am glad to see this. http://www.dfsd.com.ReplyDelete
Thank you so much for writing such a detailed and useful review of keto diet. I thin you'll also may like this article http://www.agsinger.com/hemorrhoids-on-keto-is-your-diet-the-cause/. It helped me a lot in solving some delicate problems connected with keto. I believe the Keto diet is an amazing sugar detox and it’s worth trying especially if you need that sustainable energy throughout the day. Everyone knows that fat has been proven to be a far better quality fuel than glucose.ReplyDelete
Food For LiverReplyDelete
Here's my point, you can purchase or make sustenance that preferences great and is beneficial for you, or you can make or purchase nourishment that isn't.buy anadrolReplyDelete
A few people discover explicit home grown eating routine enhancements powerful while there are the individuals who trust they are only unfilled guarantees that look to pull in benefits. this reviewReplyDelete
The Grapefruit Diet: One of the best known diets for hefty individuals, the benefits of this low-fat, low-calorie diet is upgraded by the consideration of grape organic products in the diet.low carb fast food guideReplyDelete
The normal trouble rating is by all accounts around 8. That is an informal, recounted based gauge.ReplyDelete
12 hour fast for weight loss
I’ve read some good stuff here. Definitely worth bookmarking for revisiting. I surprise how much effort you put to create such a great informative website. Weight Watchers DietReplyDelete
Purchase items identified with calm generator for outdoors items and see what clients state about quietgenerator for outdoors items Homegeneratorsreview on 5500 Watt Generator Pros ConsReplyDelete
After you have influenced the rundown, to guarantee that the healthy diet is consolidated with a choice of vegetables, nuts, foods grown from the ground among others.HealthReplyDelete
The consequences of being born malnourished extend into adulthood. CacahuètesReplyDelete
Each time that occurs, the media gets hold of it and a wide range of articles are written in the Wall Street Journal, the New York Times, and the TV organize news programs talk about it. Every one of the experts begin discussing the upsides and downsides, and what it intends to organizations and people. vitamin c for skinReplyDelete
That unattractive, overabundance fat will appear to be moderately minor when you begin confronting issues, for example, diabetes and heart disappointment.a good article on keto pureReplyDelete
How does the various products mentioned on the list compare, and which one can be said to be the best?Keto Diet Menu Plan For BeginnersReplyDelete
Catechin and caffeine (another major substance in green tea, but less than the content in coffee) will continue to stimulate the sympathetic nerves to continue the excitement. Under the influence of sympathetic nerves, norepinephrine will be continuously secreted. It will stimulate the breakdown of lipids in the surrounding tissues (fat, liver, skeletal muscle), release free fatty acids and promote liver lipid metabolism. In other words, catechins can promote our fat consumption.ReplyDelete
Green tea weight loss in 1 month
I read this article, it is really informative one. Your way of writing and making things clear is very impressive. Thanking you for such an informative article. make your own keto meal planReplyDelete
Nice post! This is a very nice blog that I will definitively come back to more times this year! Thanks for informative post. AugmentinReplyDelete
Knowing canine cancer diet nutrition needs for your pet can make a huge difference in the survival of your pet through the treatments needed to get rid of the cancer. Cancer is a vicious enemy regardless of what species it attacks. If the cancer itself does not kill its host, which it will do in a matter of time, then the treatments can be just as hard on the victim. Keto BHBReplyDelete
Great post, please keep on sharing amazing article like this! It makes me happy reading your post. To know more about us you can visit on Keto Food Online In UAEReplyDelete
I admire this article for the well-researched content and excellent wording. I got so involved in this material that I couldn’t stop reading. I am impressed with your work and skill. Thank you so much.ReplyDelete
Keto Meal Delivery Miami
Very nice article, thanks for sharing the information. we also provide Top 10 Foods for The Ketogenic Diet which is very helpul for body fitness. for more information visit on our website.ReplyDelete
If the Medigap policy is affordable, this is the best time to purchase. medicare insurance brokers near meReplyDelete
This particular papers fabulous, and My spouse and i enjoy each of the perform that you have placed into this. I’m sure that you will be making a really useful place. I has been additionally pleased. Good perform! Satta king upReplyDelete
It's awesome in favor of me to have a web site, which is helpful designed for my know-how. thanks adminReplyDelete