I’m one to get long winded.
You summed it up very well.
I’m one to get long winded.
You summed it up very well.
Ok, I did not know that… very interesting. Thanks for pointing it out. More research needed I think.
Can everyone’s body become fat adapted or do some people never get into this? Do you know the science behind it?
Can some peoples cells not process fat adaption even if I’m ketosis? Or is it just a matter of time for each person?
It’s just a matter of time. Usually by 90 days of lowered carbs liver glycogen has been depleted for long enough for the body to adapt and burn fat rather than glucose as its primary energy source.
Yes a very small percent of people have a genetic disorder that does not allow fat burning to work properly(you would know it), there is a similar one that does not allow the liver to produce ketones properly.
I would treat them as two separate things(fat adaption and ketosis) that can more less run independent of each other, but both rely on insulin and glucagon to control. Beta oxidation(fat burning) is always happening even when you are an extreme diabetic, your body needs fat for many functions outside of energy. Insulin impairs that to a great degree, insulin resistance will of course also plague you since it tends to keep the cells running on glucose. Most of us when we start are very metabolically damaged, the mitochondria have not been running on fat to any great extent and impaired from doing so readily(metabolic flexibility) but slowly they do heal. Beta oxidation by a long shot is at the cellular level with the exception of a few like blood cells which need glucose, opposed to only in the liver making ketones. Ketogenisis is driven almost entirely by the liver production of ketones and happening at the same time GNG and glucose production is happening. Some consider that both are more like emergency backups when you cannot shift quick enough from one to the other. The shift from external intake of glucose to internal regulation by the pancreas and liver is a pareto shift of about 80% to 20% for glucose and inverse for fat burning when things are in working order which takes some time(and it varies person to person). You are always burning both, its just a matter of which way the pendulum has swung. It took me six weeks to really notice and I would say fully at about 3 months be fat adapted. After a year and a half I rarely produce ketones to any great extent unless I am fasting, I don’t check all that regularly anymore either though. Beta oxidation is were it is at for me, metabolic flexibility is an endgame goal IMHO, ketosis is just a stop on the route.
Omg… Just when I think that I fully understand the diet I realize something important was not clear to me before. I had not previously understood that the amount of ketogenesis declines after fat adaptation. Do you have a source where I could read more about this process?
In that I assume you are talking about the Beta Oxidation part(fat adaption)? I should also preface I am now carnivore more or less so I don’t follow all the ketogenic macro guides anymore but it is essentially the same otherwise as far the process using fat for energy.
Dr. Bikman(The low carb down under/breckenridge channel is the best source) on you tube is probably the best place to understand the more complex ends of the WOE, high intensity health on you tube as well is another good place for advanced biochem stuff. Mike interviews a lot of relevant experts and asks pertinent questions, although personally I think he is a little of the deep end(as much as someone who only eats animal products can question). I am not sure I have that in one specific place otherwise seen a really good explanation.
My understanding is that it’s not so much a decline as a better matching of output to demand.
Ketone bodies are intermediate products of fat metabolism. Fatty acids cannot cross the blood-brain barrier, but β-hydroxybutyrate, one of the ketone bodies, can, and the brain does very well on it. Muscles are equipped to metabolize fat, ketones, or glucose, but in a glucose-rich environment, the fat pathways get damages or shut down and need to be restarted. So the liver starts producing ketones as soon as there is no longer enough glucose in the blood to satisfy the cells that have been using it, and it also starts making glucose out of protein for those cells (primarily the red blood cells) that can use only glucose.
The muscles start metabolizing the ketones, but after the right hormonal shifts (takes about six to eight weeks, usually), they start using fatty acids and they refuse to take in glucose or ketones, so that those cells that need them can have them. This is when we become fully fat-adapted.
Since people generally see a drop in ketone bodies excreted in urine and breath, and often the serum β-hydroxybutyrate level seems to drop after fat-adaptation, it appears that ketone production and use are better matched at this point, because there is less waste.
I mean, yes, it’s a decline in the sense that the liver is making less, but by the same token, it’s wasting less. It’s not a decline in the neegative sense. After all, a factory that stops sending part of its output to the landfill is reducing waste, not suffering a decline in production.
Thank you, that was very helpful. I’m left with something I don’t understand though. If a) ketones are a byproduct of fat metabolism and b) fat metabolism is still happening at a fair clip because we aren’t fueling with glucose anymore, and c) ketones are being used more sparingly by certain tissues such as muscles, then wouldn’t we expect the opposite, in other words more wasted ketones?
Your short answer is better than the article.
Good question! I haven’t an earthly. Would you like my guess?
My guess is that (a) in the early stage, before fat-adaptation, there is a lot of fat floating around and no sugar, so the liver knows to take all the fat and partially metabolize it into ketones. (Muscles can metabolize ketones without being fat-adapted.) Then (b) later, after fat-adaptation, the muscles grab most of the fat to use directly, since they no longer have to wait for the liver to make ketones. This reduction in circulating fat tells the liver that the muscles have come on line, so all it needs do anymore is make ketones for the brain, etc.
I’m very proud of myself for coming up with this. It may be completely wrong, but this is my story and I’m sticking to it!
Anybody who has the real scoop, this would be a great time to chime in, right about now, lol!
Thanks for answering. It might very well be right. I’ve had flu the last few days and have been in too reduced a mental state to try and see if I can find an answer out there on the wild webs. I’ll give it a go in a couple of days but if I can’t sort it out, which is likely, I’ll try posting a question to “show me the science” and see if anyone bites.
Muscles use the fatty acids created when the fat molecule is split into glycerol and fatty acids. The glycerol goes to the liver for production of either glucose or ketones.Since limited glucose is being created, there may be a reduction of ketones produced. It’s still an overall state of lipolysis. One way to look at adaptation is to consider that your cellular mitochondria are no longer confused and are able to use fatty acids efficiently.
I’m not following this part. Could you expand on it. Why is glucose production limited? Why would limiting glucose lead to a reduction in ketone production?
“Limited” meaning small amounts. Gluconeogenesis using only protein as the substrate can only produce limited amounts. That’s why high protein doesn’t work. If glucose is being produced via Gluconeogenesis your body may choose to produce fewer ketones.
I don’t know that it necessarily does. In the absence of dietary carbohydrate (i.e., glucose), the liver makes glucose out of amino acids from the dietary protein, a process called gluconeogenesis. This process is regulated by the insulin/glucagon ratio, which is quite low when carb intake is low. Glucagon also stimulates the production of ketone bodies, for cells that can use them. High insulin puts a stop to ketogenesis. I believe that the liver is quite capable of producing glucose from protein and ketone bodies from fatty acids simultaneously. My point in the earlier post was simply that there is less need of ketone bodies, once the muscle cells adapt to metabolizing fatty acids from scratch.
Oh, and gluconeogenesis produces a limited amount of glucose, because the body only needs about a tablespoon circulating in the blood at any given time. It’s a demand-driven process.
Yeah, we’re here 24/7.
We’re keen for keto and to help others because it’s great.
Hang in there.
I just want to make sure I have everything right. Here’s what I understand - please correct me if I’m wrong:
Ketosis is a state in which you body makes ketones for fuel rather than using carbs/glucose.
It’s possible to get into ketosis several ways: reducing carbs, fasting, exercise (maybe others?).
Doing those things lowers both glucose levels and insulin.
Our bodies can make small amounts of ketones without restricting carbs or fasting, but doing those things dramatically increases the production of ketones.
When we measure ketones in the urine, breath or blood, we are measuring wasted ketones. They are a by-product of ketosis, but our bodies are expelling or excreting them, not using them to burn fat. (Is that true for blood ketones too?)
So after awhile, it’s kind of useless to measure ketones because the body gets better at using them for energy, resulting in less waste.
Moreover, ketone levels change throughout the day, so just because they are high in the morning and low in the afternoon does not mean that you did something wrong and you’ve suddenly been “kicked out of ketosis” or stopped burning fat and have to go back to square one.
Fat adaptation is the result of ketosis and is the process of your body being able to use primarily fat in the form of ketones and fatty acids for fuel. (Not sure where fatty acids come in. Amy Berger says we can’t measure fatty acids, so maybe that’s why we don’t discuss them much. Were they there all along? Produced by ketosis?)
Fat adaptation results in increased energy (being able to lift more weights, cycle longer, etc.), weight loss, improved glucose levels, hormone regulation, lower blood pressure? Other things or do we have to be keto adaptated to get more benefits?
It takes longer to become fat adapted (weeks or months vs. days to get into Ketosis?).
Keto adaptation, which seems to be a Stephen Phinney/Jeff Volek term, occurs after your body has been in ketosis for a few weeks and becomes better at running on ketones and fatty acids. This results in many health benefits (losing weight, lowered glucose, better brain function, hormone regulation, etc.).
These seem to be the same health benefits as fat adaptation.
I can’t tell whether the timeline is: ketosis - fat adapted - keto adapted or ketosis - keto adapted - fat adapted.
I assume this is variable, depending on how sick or healthy or fat adapted or keto adapted you are.
Whew! That was a lot!
“Unused” is perhaps a more-useful term, especially where blood ketones are concerned. Of course, any ketone bodies that are excreted are “wasted,” because they are not metabolized for their energy. The point of calling them wasted is to distinguish them from the ketone bodies that get metabolized (and unfortunately, there is no way to measure how much ketones are being metabolized, although the respiratory quotient is a reliable measure of total fattty acid metabolism).
Fatty acids are the fat that we eat. They are transported through our bloodstream and stored in our adipose tissue (fat cells) in the form of triglycerides, which are three fatty acids bonded to a glycerol backbone. Whole triglycerides cannot be passed through the wall of an adipocyte (fat cell), so they have to be lipolyzed (broken down) to be passed through the cell membrane in either direction, and then reassembled into triglycerides in order to be stored or transported. The process of lipolysis is simply the disassembly of a triglyceride into its component fatty acids. It is the free fatty acids that get metabolized in fat-adapted muscle tissue. It is the liver that takes fatty acids and produces ketone bodies (acetoacetate, β-hydroxybutyrate, and acetone) from them. The ketone bodies are “intermediate metabolites” of fatty acids, which means that they are produced about half-way through the process of fatty acid metabolism, much as charcoal is an intermediate combustion product of wood-burning. And like charcoal, they can be used for energy by the cells who can use them. (Some cells love ketone bodies, even though they cannot metabolize fatty acids.)
A slight modification, if you don’t mind: improved glucose and insulin levels result in better hormonal regulation of weight, which results in fat-adaptation, further hormonal regulation, and lower blood pressure. Fat adaptation provides abundant energy, because even a lean person has thousands of calories of energy stored as fat, whereas the body can only maintain about 15 grams of glucose (60 calories) in the bloodstream at one time.
Dr. Phinney makes a distinction between fat-adaptation and keto-adaptation, but I am not certain what he means by it.
This is because of the metabolic flexibility bestowed by fat-adaptation. The body can become unused to metabolizing fatty acids, but hyperglycemia (too much blood sugar) is a dangerous emergency, so the body never loses the ability to metabolize (or store) glucose.