I’ve just begun the keto lifestyle, and I’m loving it!
Question, please: What’s the difference between being in ketosis and being fat adapted? I thought they were the same, but people say ketosis can begin within a week or so, while fat adaptation can take up to 6-8 weeks.
You are keto when your body starts creating ketones but you are not fat adapted until you start efficiently using stored body fat as fuel. It usually takes a few days for people to get into ketosis but a few weeks to become fat adapted. A lot of people don’t feel an energy boost until they become fat adapted. When you are fat adapted you also feel the need to eat less often. Keeping an eye on these two things helps you know when you are becoming fat adapted.
My take is ketones start getting produced as a by product of burning fat - whether ingested or body fat. So, soon after you stop ingesting carbs, the body has to start burning fat, and it starts making ketones - an important by product.
Now, as you continue in this low carb ingestion, the body has to keep burning fat. it gets better at it. It ramps up the hormones that do this. you are exercising the fat burning process, so it gets stronger. This seems to take 2-8 weeks before it is sufficiently developed. Now, your body can efficiently break down fats into free fatty acids and ketone bodies. Most of your body starts using these free fatty acids directly. Those few parts that cannot - eg brain, heart, kidney, Red blood cells - use the ketones if they cant, with a small subset continuing to live on glucose.
This Fat burning/churning maelstorm is the end goal - and is called fat adaptation. Now your body can efficiently break down fats at a sufficient pace, and make ketones and glucose in the correct amounts, so your entire body gets happy. hunger abates, and energy levels go up - waaaay up.
One of my favorite questions, ketosis is a defined level of being ketogenic by Dr. Phinney and Dr. Volek, its somewhat pulled out of their butts but its at 0.5 mmol/L or higher of ketones. There are by their definition multiple levels past that but for practical purposes its being above 0.5 mmol/L in your blood. This can take anywhere from a few hours to a week depending upon the person and the condition that they start to become ketogenic. Many people are ketogenic overnight but not in “ketosis” .
Being keto adapted is when your liver(mostly) is generating excess ketones and you are now using them primarily vs glucose. Your cells that can accept ketones don’t do it right of way and your liver cannot make enough of them right of way either. You are still using glucose that never goes away, but you are not using it as much. As you keto adapt you start really increasing the passage of fat directly to the mitochondria in most of your cells, some cells like the brain cannot use fat directly and still rely on glucose or ketones. At a tipping point of your cells doing this you become fat adapted. Now you are not relying on your liver for all of your energy needs and you are more metabolically flexible.
Often people have to fix the mitochondria in the cells to get them working properly again, and this is what takes the time between keto and fat adaption. The effects of insulin plays a giant role in this as well, people who are IR or T2D tend to take a lot longer to become either because there insulin levels are pulsing so high.
And, to pile on, there are two stages of adaptation: the first that occurs after about 6 weeks as described previously here, and the second that occurs after 6 to 9 months when you become “bonk-proof” from an athletic performance perspective, meaning you can exercise at low to moderate intensity for over 2 hours on an empty stomach without having to revert to carbs.
When you are at Stage 2, you can “target carbs” to win the Tour De France. Or kick teenager’s butts down a ski slope at 4:00 PM, just saying.
My understanding is that it is only the liver that can process fat that results in ketones, and this is the result specifically of gluconeogenesis. Much of the rest of the body can process fat for energy but does not produce either glucose or ketones.
My understanding may be wrong, and I write this to check if this is other people’s viewpoint as well. Corrections welcome. I really want to understand this well.
I think I may have oversimplified, and resulted in an inaccurate description. Wikipedia describes that TriGlycerides can be broken down by stripping away the fatty acids from the glycerol backbone directly in the adipocyte (fat cell). However, Alec is probably accurate in that only the liver can further breakdown the glycerol and produce ketones and glucose. I say probably not because I doubt Alec, but because I don’t know and am deferring.
I doubt myself all the time. It is a pity Ancel Keys and a few of the current Dietary Guideline committee folks don’t share this trait!!
From Wikipedia (that well known font of all Knowledge and Wisdom):
Ketone bodies are three water-soluble molecules (acetoacetate, beta-hydroxybutyrate, and their spontaneous breakdown product, acetone) containing the ketone group that are produced by the liver from fatty acids during periods of low food intake (fasting), carbohydrate restrictive diets, starvation, prolonged intense exercise, alcoholism or in untreated (or inadequately treated) type 1 diabetes mellitus. These ketone bodies are readily picked up by the extra-hepatic tissues (tissues outside the liver) and converted into acetyl-CoA which then enters the citric acid cycle and is oxidized in the mitochondria for energy. In the brain, ketone bodies are also used to make acetyl-CoA into long-chain fatty acids.
Ketone bodies are produced by the liver under the circumstances listed above (i.e. fasting, starving, low carbohydrate diets, prolonged exercise and untreated type 1 diabetes mellitus) as a result of intense gluconeogenesis, which is the production of glucose from non-carbohydrate sources (not including fatty acids). They are therefore always released into the blood by the liver together with newly produced glucose after the liver glycogen stores have been depleted (these glycogen stores are depleted within the first 24 hours of fasting).
I believe to further drill down this its only the brown fat cells that can tear apart the trigs, not 100% certain of that but that is part of there function in life. When white fat starts to turn some brown(beige) they will also do this.
Today I listened to a recent Primal Blueprint podcast where the host (Brad Kearns?) describes the difference between keto-adapted, and fat-adapted. I never knew there was a difference, but he states that keto adapted is when you’re using ketones for energy and fat adapted is when you’re a fat burner without ketones (so low carb but not keto level low).
Anyone ever hear this? News to me
And I think that assumption on the podcast is actually incorrect, when you are in ketosis you are fat burning, when you are fat adapted your cells can burn fat, being one or the other is not really mutually exclusive and on the same token they are not under normal circumstances without each other while being keto. You can burn fat through your cells and not be producing ketones, but that would be on either edge of a insulin event. Insulin controls both, but glucagon only controls ketosis as a slave to insulin, so you could be with out one and not be a glucose burner primarily. This could happen after carb loading when your blood glucose is lower and so is your insulin goes lower but your liver glycogen is not low so you have low glucagon. Your cells can burn the fat but your liver is probably not making much in the way ketones yet since it can release glucose for a while. This is probably the best example of metabolic flexibility that fat adaption can provide.
When we are catabolic (high glucagon) and have low blood sugar you will be in ketogenic state, and probably in ketosis. The liver uses the mobilized fat byproduct for making glucose via GNG from the glycerin that is released when the trigs are broken down into fatty acid. So when ketones are being made most often so is a small amount of very regulated glucose, as you fat adapt your body uses the glucose less and the fatty acids more at the cellular level instead of relying on just the liver so less ketones are made. Your body is most always in a state energy balance, the difference is were that energy is coming from and how it is being used.
After being fat adapted for a while now I have gone long stretches with minimal ketones sometimes none that I can detect. Typically when I have fasted for 20 or so hours I really start to see the ketones on my breath meter like I used to be a few months ago all the time.