What Is Ketosis?

What is ketosis?

Let’s keep this simple.

Nutritional ketosis is a metabolic state that happens when your body has less carbohydrate available and starts relying more heavily on fat for fuel. As your liver breaks down fat, it produces substances called ketone bodies, or simply ketones.

Ketones can then be used as fuel by your brain, muscles and other tissues.

And yes, I find this stuff pretty fascinating!!

When you reduce carbohydrates enough, your body becomes much more dependent on fat and ketones for energy. But there’s an important distinction here.

Being in ketosis does not automatically mean you’re burning your stored body fat.

You can be burning fat from the food you just ate, fat from your body, or a combination of both.

That little detail becomes very important when we're talking about weight loss. We’ll get to that in a moment.

Nutritional Ketosis NOT Diabetic Ketoacidosis

The words ketosis and ketoacidosis sound very similar. But hold up! They're not the same thing.

Not even close.

Nutritional ketosis is a normal metabolic state that happens when you restrict carbohydrates, or you're fasting and during other situations where the body is relying more heavily on fat and ketones for fuel.

Diabetic ketoacidosis, or DKA, is a serious medical emergency. It happens when there isn't enough effective insulin so then ketone production becomes dangerously high, which leads to metabolic acidosis. DKA is most often associated with diabetes, particularly Type 1 diabetes, but it can also occur in people with Type 2 diabetes. It can even happen when blood glucose isn't dramatically elevated.

So please don't confuse the two.

If you tell someone you're in ketosis and they immediately look at you like you've announced that you've joined a dangerous cult, you might have some 'splaining to do!

The word ketosis by itself does not mean you're in danger.  And the word ketoacidosis absolutely deserves respect.

How Do You Measure Ketones?

If you want to know whether your body is producing ketones, you can measure them.

There are three main ketone bodies:

• Acetoacetate
• Beta-hydroxybutyrate
• Acetone

You can measure ketones in your urine, breath or blood.  Each method tells you something a little different.

Testing Urine for Ketones

One simple way to check for ketone production is with a urine test strip.

These strips measure acetoacetate, one of the ketone bodies that your body excretes in urine.

 Bayer Ketostix Reagent Strips Urinalysis is the brand I'm familiar with.

You simply pass the testing strip through your urine stream when you pee. Or you can collect some urine in a small jar and dip the strip into it. 

Then you wait the amount of time specified and compare the colour of the strip with the chart on the container.

The colour usually progresses from negative through trace, small, moderate and large.

It's a wonderfully simple little test. But there is an important catch.

Urine ketones don't tell you exactly how much fat you're burning right now. They tell you that your body is producing ketones and that some acetoacetate is being excreted.

As your body becomes more adapted to using ketones, urine testing can also become less useful because your body becomes better at using ketones instead of simply peeing them out.

So I wouldn't obsess over the colour of that little strip.

Testing Breath for Ketones

Another option is a breath ketone meter. I haven't gone that route.

It's a small handheld device that you breathe into. It measures acetone, the ketone that is released in your breath.

The technology is somewhat similar to a breathalyzer, except you're measuring acetone rather than alcohol.  And no, you don't have to worry about "blowing over the legal limit" if you get pulled over for suspected DUI. Your ketones aren't alcohol!

Breath ketone meters generally report results in parts per million, or ppm.

The important thing to understand is that breath ketone readings are not directly interchangeable with blood ketone readings. Different devices also use different measurement methods.

So if you're using a breath meter, follow the manufacturer's instructions and use your readings as a way to track your own pattern rather than trying to make an exact comparison with somebody else's blood ketone number.

Testing Blood for Ketones

Blood testing is my favourite method when I want a more precise measurement.

It's done much like checking your blood glucose. You prick your finger, put a drop of blood on a ketone test strip and insert the strip into the meter.

The result is usually displayed in mmol/L.

Blood testing measures beta-hydroxybutyrate, which is the main ketone circulating in your blood.

For nutritional ketosis, a blood beta-hydroxybutyrate level of about 0.5 mmol/L or higher is commonly used as the definition.

But here's something very important.

Higher ketones are not automatically better.

Higher ketones are not automatically better. There's no need to play the "How high can I get my ketones?" game. That's not the goal.  The goal is metabolic health.

Blood ketone testing is more expensive than urine testing because the strips can be pricey. The meter itself is often quite reasonable. That's one reason I don't test every day. Once a week is plenty for me when I'm simply tracking my own pattern.

My FreeStyle Libre 2 system can use both blood test strips and ketone test strips. However, the Libre 2 sensor itself used as a Continuous Glucose Monitor (CGM) only measures glucose, not ketones.

Newer sensor technology is now available that can continuously monitor both glucose and ketones.

Do I Have to Check for Ketosis?

Nope.  Not at all.  Some people love tracking and measuring everything.  Ketones included.

I'm one of those people!

But you don't have to measure ketones to eat a low-carbohydrate diet or improve your metabolic health.  You can also notice changes in the way you feel when you're eating in a way that produces ketosis.

Some people notice that they're less hungry between meals. Some notice steadier energy. Some notice improved mental clarity.

And some people notice absolutely nothing dramatic.  And that's okay too.

Your body doesn't have to give you fireworks every time it changes fuel sources.

What the Heck Are Ketones Anyway?!

Ketones are chemical compounds produced by your liver when it breaks down fat.  Your liver can make ketones from fatty acids released from your body's fat stores, as well as from dietary fat.

This happens when carbohydrate availability is low. Fasting and prolonged exercise can also increase ketone production.

Ketones are an alternative fuel source for the brain and other tissues.  And this is one of the really interesting things about human metabolism.  Your body is not designed to run on one fuel forever.

It has several fuel systems and is remarkably good at switching between them.

How Long Does It Take to Get into Ketosis?

This is one of those questions where the honest answer is:

It depends.

How quickly you begin producing measurable ketones depends on things such as your carbohydrate intake, how much glycogen you have stored, your activity level and your individual metabolism.

There isn't a magic 24-hour timer that suddenly announces:

DING! Congratulations! You're now in ketosis!

Glycogen is stored carbohydrate. Your liver and muscles store glucose in this form, and your body draws on those stores when it needs glucose.

When you dramatically reduce carbohydrate intake, insulin levels generally fall and the body increases its use of stored fat. As carbohydrate availability remains low, ketone production increases.

The transition isn't the same for everyone. You might see measurable ketones fairly quickly. Someone else might take longer.

And then there's the adaptation period.

When you make a big change in carbohydrate intake, you can feel pretty lousy for a few days. Fatigue, headaches, dizziness and changes in exercise performance are common complaints.

People often call this the "keto flu."

It isn't influenza.  It's a nickname for the collection of symptoms some people experience while adapting to a very low-carbohydrate diet. You're not sick.

Once you've adapted, you might notice steadier energy, less hunger and better mental clarity.

Or you might not.

We're all wonderfully annoying individuals when it comes to metabolism!

Does Ketosis Guarantee I Will Lose Weight?

No. And this is where I really want to slam the brakes on the whole "ketosis equals weight loss" idea.

Being in ketosis does not guarantee that you'll lose body fat. Why?

Because being in ketosis means you're producing and using ketones. It does not tell you where all of the fat you're burning came from.

Let's say you eat a meal containing a very large amount of fat.

Your body has access to that dietary fat and will use some of it for energy. If you're eating more energy than your body needs, some of that dietary fat can still be stored.

You can be in ketosis and still gain body fat. That's why I don't want you staring at your ketone meter and thinking, "Woohoo! I'm burning fat, so I must be losing my body fat!"

Not necessarily. Ketosis is a metabolic state. It's not a magic fat-loss switch.

Do I Have to Be in Ketosis to Lose Weight?

Absolutely not. Your body can burn glucose and fat for fuel without being in ketosis.

In fact, a metabolically healthy person is generally able to switch between fuel sources depending on what the body needs.

This ability is often called metabolic flexibility.

After a meal, your body has access to the energy you've just eaten.

Between meals, during fasting and during exercise, your body increases its use of stored fuels.

You don't need to be in ketosis all the time to be metabolically healthy.  And you don't need to chase a particular ketone number to lose body fat.

That person who can eat a large amount of carbohydrate, maintain stable energy and comfortably go several hours between meals without constantly thinking about food?

Ummm... Yeah. That person is not me.  At least, not historically!

In Conclusion... What Is Ketosis?

So, what is ketosis?

It's a metabolic state in which your body is producing ketones because it's relying more heavily on fat for fuel.

That's it.  It isn't a disease.  It isn't diabetic ketoacidosis.

It isn't a requirement for weight loss. And it isn't something you need to obsess over.

Healthy humans move in and out of ketosis. Ketone production naturally increases during periods of fasting, carbohydrate restriction and certain types of exercise.

For me, the bigger question isn't:

"Am I in ketosis?"

It's:

"Am I eating in a way that supports the health I want?"

That's where I want you to put your attention.

Eat real food. Cut way back on highly processed foods.

Get rid of the constant stream of sugar and refined carbohydrates. Eat satisfying meals.

Give your body a chance to experience what it feels like when you're not constantly feeding it.

And if you're struggling with that last part, please don't beat yourself up.

I know how easy it is to decide that you simply don't have enough willpower. I also know how quickly perfectionism can turn one cookie into, "Well, I blew it anyway, so I might as well eat the whole package."  That's not a character flaw.

Changing the way you eat can be hard.

Sometimes you need more than information. You need someone in your corner who understands the struggle and can help you work through the thoughts, habits and roadblocks that keep getting in your way.

That's where coaching comes in.  And that's exactly what I do.

If you're ready to stop fighting with food and start building a healthier relationship with eating, I'd love to help.

Read more about my services here.

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