November 19


The One Way to Know If the Keto Diet Is Working

Unlike most diets that simply restrict the number of calories consumed, the ketogenic diet converts your metabolism from burning sugar (glucose) to burning fats (ketones) for fuel. This metabolic state where fats (ketones) are used as fuel is called ketosis. There is only way to know if your body is truly in ketosis – test for it. After you have experienced ketosis before and know what it feels like, you may be able to know when you are in ketosis without testing for it. Until that time, the only sure way to know if you are in ketosis is to test for it.

The ketogenic or “keto” diet emulates how our ancestors ate during seasons when carbohydrate-rich foods were not available. The great thing is you don’t lose weight by going hungry while restricting calories. You simply exchange the foods you are eating with keto-friendly foods. A new book by Bill McIntosh called BodyReboot, talks about the health and weight loss benefits of the ketogenic diet and gives you all the tips, tricks, shopping lists and recipes to get started. If you are interested in learning how easy it is to get started on a keto diet, check out this FREE book offer from the BodyReboot program.

There are a number of ways to test for ketosis. Dr. Jockers has listed 5 ways to know if you are in ketosis.

5 Ways to Test for Ketosis

1. Blood Ketone Meter

This measures BHB and is considered to be the most accurate way to measure ketones.  These have the ability to determine the ketone level in your blood precisely but they are also pricey and invasive.  Personally, I freak out every time I have to prick my finger!!

The Precision Xtra blood glucose and ketone meter is the most common meter used and you can get it for about $30.   The expensive part is the ketone test strips here which can cost $4 each.   If you are looking at testing yourself every day it is going to cost you $120 a month and the $30 meter.  Here is a starter kit you can get on Amazon

I would personally recommend the Keto Mojo which is a newer company and is very effective and really well priced at $50 for the meter and the lowest rates you can find online for ketone strips (99 cents per strip) and blood glucose strips (30 cents per strip).   After the initial cost of the meter, the cost of testing yourself 1 time each day would only be $30 and $60 to test 2 times per day!!  Much better overall value.

Most people will enter into a light nutritional ketosis (between 0.5-1.0 mmol/L on the meter) within two or three days.  It typically takes two to three weeks to get into a stable and optimal ketosis of 1.5-3.0 mmol/L (3).

2.  Breath Testing

A non-invasive and cheaper alternative is to measure ketones through the acetone levels in the breath. This measurement technique has been shown in the literature to be an accurate way to test for nutritional ketosis (4).

The Ketonix Acetone Breathalyzer is an easy and relatively inexpensive way to test your breath ketone levels.  One thing to remember is that breath ketones are not always a pure reflection of blood ketones because they can be affected by several factors including alcohol consumption and water intake.

I like this test the best to measure ketones because it is a one time expense $190 here but no additional costs.  You can test yourself at any time and you don’t have to draw blood in order to get a reading!  I hate needles and blood pricks!!

When you blow into the ketonix mouth piece the LED light goes off with a unique color based on the level of ketones you have produced.  The device is the size of a large marker and it has the USB cord attached at the base.  The cord is about 3 feet in length which allows you to stretch it for testing.

Set-up is easy.  You download a small program to your computer, create a profile and plug the Ketonix into a USB port.  After a few minutes of initializing, click “start,” and then blow (exhale) into the unit.

Here are the official instructions on the label affixed to the device:

  1. Connect to USB port
  2. Wait until LED turns blue
  3. Blow gently into mouthpiece for 10-20 seconds
  4. Read color after 30 seconds

This is what each different colored LED represents:

Blue = 0 – 150 nmol/L

Green = 150 – 400 nmol/L (Small)

Yellow = 400 – 930 nmol/L (Moderate)

Red = > 930 nmol/L (Large)

Both the yellow and red range are considered to correlate with nutritional ketosis.

3.  Urine Ketone Strips

The most common way people measure ketones is through the urine (acetoacetate) with simple ketone strips.  Unfortunately, these are not as accurate and are not considered a reliable analysis of blood ketone levels.

This is the most commonly used method because it is cheap and easy.  It only costs $9 for 150 strips here so that is $1.80 per month if you were to test them 1 time per day and $3.60 per month if you test 2 times per day which would be better.

One of the reasons they are inaccurate is that the body will naturally excrete more ketones before they are keto or fat adapted than after they adapt.  So if you begin on a ketogenic diet, it is natural to see high levels of urinary ketones.  Once you are keto-adapted, this should drop to small to moderate levels as the cells are more responsive to the ketone levels.  If your levels stay elevated it means your cells are not utilizing ketones effectively.

Changes in hydration will also effect the concentration of ketones.  If you are super hydrating your system the way that I teach you too, you will dilute your ketone concentration in the urine.  Very high ketone readings are often indicative of a dehydrated state.

Other changes can be seen during fasting states, eating periods, exercising and after waking up.

4.  Testing Blood Glucose Levels

This is not commonly used but it is less expensive than testing blood ketone levels.  You can use the Precision Xtra blood glucose and ketone meter here if you already have it and blood glucose strips here which are basically $0.90 per strip.

I would again recommend the Keto Mojo instead, which is a newer company that is very effective and has the lowest rates you can find online for ketone strips (99 cents per strip) and blood glucose strips (30 cents per strip).

When we are in primarily sugar adaption our body is very sensitive to low blood sugar levels (hypoglycemia) and will secrete stress hormones to boost blood sugar back up if it gets too low.  Typically the key range for this is around 75-80 mg/dl even though hypoglycemia is technically diagnosed by a fasting blood sugar less than 70 mg/dl (5).

When the blood sugar levels drop below 80 mg/dl the body responds by kicking out some cortisol which tells the body to break the glycogen (stored sugar) in the muscle and liver in order to get more sugar into the bloodstream.  This is a natural survival response as the body is concerned that sugar (its primary fuel) is scarce and the individual is in a famine period.

When the body kicks up these stress hormones there is typically a natural high at first, but if this becomes repetitive the individual can go into a state of adrenal fatigue where they are unable to get cortisol and blood sugar levels up high enough.

The end result of this pattern is blood sugar imbalances where the individual is craving sugars and sweets, they deal with fatigue and mental lethargy and often have sleep and mood disturbances.  These are all classic signs of adrenal fatigue and hypoglycemia.

When one is in a ketogenic or fat adapted state, they can be at a hypoglycemic level (under 70mg/dl) and feel very good.  They will have lots of energy, mental clarity and stamina, healthy mood and behavior and be able to sleep well.

This is a sign their body has adapted to using ketones and is not reliant on sugar as its primary fuel source so the body is no longer concerned with keeping blood sugar levels up in order to survive.

I instruct my clients, that if their blood sugar is between 50-75 mg/dl and they feel very good, mentally sharp, energetic and relaxed on a continual basis, then they are keto-adapted.

A HbA1C test looks at the level of glycation (indicative of blood sugar levels) in the red blood cell over a 90-120 day period.  The typical HbA1C on a ketogenic diet is 4.5-5.2%.  If you get your HbA1C tested and it is above this range it is an indication that you have not been in ketosis for a good period of time through the 90-120 day period.

5)    Check How You Feel

The last way to measure ketones is subjective, but important none the less.  When you are in ketosis, you should feel relaxed and mentally sharp. You have energy throughout the entire day, don’t have cravings and hardly think about food.

A common sign you are in sugar burning mode, is that you feel fatigued throughout the day.  You have cravings and are wanting to snack throughout the day.  If you notice this going on,  you are not in ketosis.

Another thing you may notice in ketosis is the smell of acetone.  It is a “fruity” kind of smell.  You may sense this in your breath, in your sweat or urine.  This is natural when you are in ketosis but it should be faint.

If you are smelling really bad and having dry mouth, it is a sign you are electrolyte deficient.  Drink more water and pick up your sodium and potassium levels.  Most of the time having an avocado or fresh lemon each day with extra pink salt or a seaweed spice mix on your foods will help to relieve this.   Staying well hydrated, drinking peppermint tea and brushing your teeth often can help reduce the fruity smell as well.



The ketogenic diet brings many health benefits in addition to weight loss. However, the keto diet works by converting your body’s metabolism into a state of ketosis where fats (ketones) are used for fuel instead of sugar (glucose). There is only one way to know for sure if your body is in ketosis, and that’s to test for it.

At the time of writing this post, we are giving away free copies of the Body Reboot book to help people lose weight and get healthy! Just cover the small cost of shipping, and we’ll send a FREE copy to your door. Go over to this page to see if copies are still available!

Bruce Fleck, PhD

About the Bruce Fleck, PhD

I help professionals overcome a health, career, or relationship crisis and make it a turning point for building a better life.

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