What Are Ketones? | Everything You Need to Know

Ketones & The Ketogenic Diet

Ketogenic diets have surged in popularity in the last couple of years, but many people still don’t understand what ketones are, and how they work in the body.

With a plethora of information out there it’s important to get the correct facts on ketones, the ketogenic diet, and how both work to benefit you and your goals.

This article will walk you through everything you need to know about ketones, ranging from what exactly they are, how they impact ketosis, and even how you can supplement with them.

Without further ado, let’s dig in!

Key Summary Points You Will Learn

  • Ketone (ketone bodies) are simple, organic molecules your body produces when carb intake is restricted.
  • The human body produces three ketone bodies as a byproduct of lipolysis: acetone, acetoacetic acid, and beta-hydroxybutyric acid (BHB).
  • How to test ketone levels at home.
  • Beta-hydroxybutyric acid is available as an exogenous ketone supplement.
  • Ketones are ultimately an alternative energy source for your body when you limit carb consumption.
  • When ketosis takes place, acetoacetate is present in large amounts throughout the body, which can then go on to form BHB and acetone.
  • Ketones mediate the benefits of ketosis, such as supporting weight loss, reducing the risk of type-2 diabetes, enhancing cognition, and much more.

What Are Ketones?

Biochemically speaking, ketones are simple, organic compounds. Ketones are ‘simple’ molecules because they don’t contain any chemical groups that readily react.

In humans, three different ketones (also referred to as ketone bodies) are made in the mitochondria of the liver, including:

The image below shows the chemical structures of these three ketone bodies:

How Do Ketones Work?

Ketones serve as an alternative energy source for the human body, specifically our mitochondria (the ‘powerhouse’ of cells) when carbohydrate intake is limited. They are a byproduct created when the body breaks down fat.

In simple terms, when you are eating a high-fat, low-carb diet (ketogenic diet) your body will begin to break down fat (creating ketones as a byproduct) for energy instead of carbohydrates (sugars).

While you might argue that glucose (sugar) is the primary source of energy in humans, it is not essential for our survival.

Ketones, on the contrary, are byproducts of fat metabolism in humans when carbohydrates are restricted and are thus necessary substrates for us to live.

Note that BHB is not technically a ketone since it contains a reactive hydroxyl group where a double-bonded oxygen would usually be.

Nevertheless, BHB still functions like a ketone in humans and can convert to energy (via acetyl-CoA), just like acetoacetate and acetone can be; however, the conversion of acetone to acetyl-CoA is rather inefficient.

Entering Ketosis – When and Why Does the Body Produce These Ketone Bodies?

Ketone bodies, particularly acetoacetate, are made from the breakdown of fatty acids. Fatty acids become a primary energy source in humans when carbohydrate intake is low.

When you eat carbs in low enough quantities for long enough, the body enters a state of “ketosis”.

When ketosis takes place, acetoacetate is present in large amounts throughout the body, which can then go on to form BHB and acetone. Our body may then use these molecules for energy purposes.

Remember, when carbohydrates are low, the body needs an ‘alternative’ fuel source for survival. Ketone bodies are that fuel source that steps in and powers the body.

Naturally, during periods when you limit food intake (such as intermittent fasting), ketone body production also increases for energetic purposes. This is why dietary protocols like intermittent fasting might heighten the ketosis effects of low-carbohydrate diets.

How to Test Ketone Levels

Those who are on the keto diet (especially first-timers) will want to ensure they are limiting carb intake enough to get into ketosis. As such, there are some simple at-home testing methods available that you can use to check your actual ketone levels.

These testing methods include urine testing, blood testing, and breath testing. You might also be able to have a licensed physician do blood work for your ketone levels but that isn’t necessary since most of the at-home testing methods are readily available at local drug stores (and online).

Ketosis in the human body generally begins when you have at least 0.6 mMol of ketones per liter of blood, and can go quite high once you reach a “deep” ketosis. The chart below denotes the different ketone levels and their corresponding categorization:

With that in mind, here are some quick overviews of how to test your ketone levels at home.

Urine Test for Ketones

Protocol: The urine test method is fairly straightforward; you will need to buy an over-the-counter urine testing strip made specifically for ketones. These are generally available as a product called Ketostix and can be found at many pharmacies and online.

Once you have the test strip, you urinate a small amount directly on it and it will change colors according to how many ketones you excrete. The change in color denotes different ketone body levels (read the instructions of your specific ketone urine test strips to determine your exact levels).

Pros: Urine tests for ketone levels are exceptionally simple and highly affordable, making this method the most practical. You will find products like Ketostix at most pharmacies these days.

Cons: Urine testing can sometimes produce misleading ketone levels by suggesting you’re not in ketosis when you actually are. How? When you are on the keto diet for a lengthy amount of time, your body is “fat-adapted” and you become better at using ketones for fuel. Hence, you won’t be urinating/excreting ketones as much.

Nevertheless, if you’re just starting out on the keto diet, then urine testing is a great way to assess your short-term ketone body levels.

Blood Test for Ketones

Protocol: Running a blood test for ketone levels at home is identical to how diabetics use a blood glucose meter with a lancet. You simply lance the tip of your finger and place a drop of blood on an appropriate ketone test strip which is then fed into a blood ketone meter to give you your result.

Pros: Blood testing for ketone levels is bar-none the most reliable protocol, especially for testing BHB levels. It’s also a simple method to use and can be done pretty much anywhere, assuming you don’t mind a little prick on the finger.

Cons: The major drawback of blood testing for ketone levels is the cost; the meters themselves can be pricey and the strips are generally around $10 a piece. If you shop around the Internet, you might find some decent deals. (But don’t expect to come across any options that are less expensive than Ketostix.)

Breath Test for Ketones

Protocol: For ketone level breath tests, you’ll want to purchase the Ketonix breath meter. This nifty gadget assesses the level of acetone in your breath.

Pros: If you purchase a quality breath analyzer, it will last you a very long time. The initial cost may seem a bit high, but it pays off in the long run if you plan on testing your ketone levels frequently.

Cons: Breath tests for ketone levels tell you how much acetone you have in your body, which isn’t necessarily indicative of BHB or acetoacetate levels. Thus, it’s best to do breath tests in conjunction with urine tests or blood tests (at least a few times just to ensure the results are accurate).

Is Raspberry Ketone the same as a Ketone Body? What about 7-Keto-DHEA?

Raspberry ketone seems to be a popular ingredient in many fat-loss and general health supplements nowadays. However, despite its designation, raspberry ketone is not in the same category as ketone bodies.

Many consumers believe that exogenous ketone supplements are the same as raspberry ketone supplements, which is not the case.

Raspberry ketone is a polyphenol in red raspberries that gives them their pleasant aroma and ruby red color.

Chemically speaking, raspberry ketone is similar to the compound synephrine and might have fat-loss benefits. However, it remains unknown if raspberry ketone serves as an efficacious supplement for body composition purposes.

7-Keto-DHEA is a unique derivative of DHEA (dehydroepiandrosterone), a steroid produced abundantly in humans.

While DHEA can convert to either testosterone or estrogen, 7-keto-DHEA has a slightly different chemical structure; in turn, 7-keto-DHEA imparts different effects in the body.

Some supplement companies claim 7-keto-DHEA is useful for weight loss, muscle building, and delays in the aging process.

In short, raspberry ketone and 7-keto DHEA are neither ketone bodies nor are they related to ketogenic diets. They may have separate benefits, but research is still out on their efficacy as dietary supplements.

How to Supplement with Ketones (Exogenous Ketones)

Exogenous ketones (i.e. ketones that come from outside your body) typically come in the form BHB salts. You can find exogenous ketone supplements at many online retailers nowadays. It is best to follow the label instructions; typically, an efficacious dose of BHB salts is 12-13 grams.

We recommend supplementing with ketones about an hour before you plan on exercising. You should experience increases in energy, mental acuity, and stamina.

Another added benefit of supplementing with ketones is appetite reduction (which is ideal when fasting).

Take-Home Message

All in all, ketones are physiologically essential for our health and well-being. Better yet, they provide a superb fuel source when carbohydrates aren’t available and can help with the fat loss process.

There’s also a large body of evidence suggesting ketone bodies are key for delaying the aging process; they also can reduce the risk of cancer.

Remember, when testing for ketone bodies, you are generally best going with blood sampling. Urinalysis through products like Ketostix can help in the short-term and for ketogenic diet newbies; however, that isn’t a reliable test method in the long-term.

The good thing is that once you confirm you’re producing adequate amounts of ketones, you don’t need to recheck very frequently.

With a better understanding of the ketone bodies found in humans, be sure to check out our other content on ketosis and ketogenic dieting!


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