Ketosis vs Keto Adapted

Ketosis vs Keto Adapted
Ketosis vs Keto Adapted

As you might know already, I started a Facebook group as a positive, success-oriented community of like-minded folks who are on their own keto journey.

Well, the group is growing every day (almost 15k members as of right now), which is awesome.

Because the group is growing so fast, new folks will frequently ask the same questions. There’s nothing wrong with that. Asking questions is how we all learn and grow.

So I wanted to take some time to address one of the most common questions we see in the group: What’s the difference between being in ketosis and being keto-adapted?

It’s easy to see why this is such a confusing topic, and it’s not made easier by the common misconceptions (and just plain errors) that seem to abound.

First, let’s address the subject of ketosis. Ketosis is a situation where your body is producing ketones. There are three ketone bodies: acetone, acetoacetate, and beta-hydroxybutyrate (BHB). Ketones are produced hepatically (which is a fancy way of saying “by the liver”) as a product of breaking down fatty acids.

But there’s a bit of a problem with this simple definition of ketosis. You see, your liver is constantly breaking down fatty acids, and therefore creating ketones, but it would be difficult to say that you’re in ketosis. That’s because the level of ketones isn’t high enough to be considered ketosis.

So, having ketones in your body doesn’t necessarily mean you’re in ketosis.

Okay. Cool.

Cool, cool, cool.

But, hey…so…wait a sec. Is there, like, a level of ketones that DOES mean you’re in ketosis?


Yes, there is.

Dr. Stephen Phinney is the grandmaster of ketogenic research (along with Dr. Jeff Volek), and he’s the person who coined the term “nutritional ketosis.” Before Phinney and Volek started doing their work (and challenging almost everything that was considered nutritional orthodoxy), the state of ketosis was associated with two primary situations: starvation and diabetic ketoacidosis. Neither of these are relevant to this, though. Suffice it to say keto is not about starvation, nor is it related to ketoacidosis (which affects Type 1 diabetics).

But Dr. Phinney changed all of that when he coined the term, “nutritional ketosis.” He also provided a lower and upper limit to the definition. By his definition, nutritional ketosis is the state of ketone production that lies between 0.5 mmol/dl and 5 mmol/dl. So that’s the definition I use.

If you’re producing ketones at a level betwen 0.5 mmol/dl and 5 mmol/dl, then you are in ketosis. That’s that.

Okay…not exactly…there are some other considerations, but for the sake of this article, that’s that.

So, let’s go over that one more time. Ketosis, as I’m using the term, means you are producing between 0.5 mmol/dl and 5 mmol/dl of blood ketones.

Now, what about keto-adapted. Keto-adapted means you are using fat as your primary fuel source. In order for ketones to be a primary fuel source, a few things have to happen.

You have to remove glucose/glycogen as an optional fuel source.
You have to produce ketones within the “nutritional ketosis” range.
You have to produce ketones within the “nutritional ketosis” range long enough for your body to switch to fat as your fuel source.

When those things happen, you’re keto-adapted.

One of the reasons this takes a little while is because there is an interesting interplay between the energy needs of your skeletal muscle and your brain. When ketone levels are low, your muscles will use ketones for fuel. But as those levels increase, your muscles will burn fat, instead (remember, ketones are BYPRODUCTS of fat metabolism). Your brain, on the other hand, will use ketones in proportion to the amount present in the blood. In other words, the more ketones in your blood, the less ketones your muscles use (muscles start to use fat, directly, instead of ketones) and the more your brain uses.

When you reach a point where your muscles are using fat for fuel and your brain is using ketones for fuel, you are keto-adapted.

So being keto-adapted isn’t the same thing as being in ketosis, but you have to be in a state of ketosis long enough to become keto-adapted.

Ketosis can happen when you wake up, because you didn’t eat for 12 hours. But keto-adaptation takes some time.

So there you go. Hopefully, this clears it up.


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