TONE FAQ (Frequently Asked Questions)

Here are the most Frequently Asked Questions about the new TONE device.

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Q: How does measuring acetone show our fat loss?

A: Did you know that we actually breathe out our fat? Breath acetone are ketones that have been first generated in the liver from fatty acids coming from our adipose tissue (fat cells) when they are being oxidized or burned for fuel. It has been established in studies that breath acetone ketones may be used to monitor fat loss as a strong correlation exists between increased breath acetone ketones and the rate of fat loss.

There are several factors that affect the measurement of breath acetone, and it is mostly affected by changes in:

-dietary macronutrient composition,

-caloric restriction,

-exercise,

-other factors that increase fat metabolism

Acetone is a metabolite of fat catabolism or break down, and it is produced in high amounts in individuals undergoing caloric restriction or ketogenic diets for weight loss via changes in macronutrients and calories, often in association with intermittent fasting, exercise. Breath acetone measurements are useful as a motivational tool during dieting, and for monitoring the effectiveness of weight-loss programs. Using breath acetone analyzers to quantify breath acetone concentrations of dieting subjects, a correlation was established between breath acetone concentration and rate of fat loss.

This study shows the correlation between breath acetone and fat loss rate of dieting and non-dieting groups and in two individual dieters (right).

In this study, from day 8 to day 30, the daily rate of fat loss remained almost parallel to the daily breath acetone concentration of the dieters and averaged 114 g/day (SD17.4, range 100-152 g/day). The daily average acetone concentration of the dieters during this period was 290 nmoIJL (SD 8.1, range 280-300 nmol/L).

According to this study, breath acetone is "the most promising as biomarker for tracking metabolic changes. It originates from lipolysis where fatty acids undergo hepatic β-oxidation to acetyl coenzyme A and acetoacetate, that is degraded into volatile acetone and β-hydroxybutyrate (BOHB)."

Q: When should I take readings on the Tone?

A: It is optimal & recommended to only take readings when fasted. For maximum accuracy, only test during your fasted window in order to avoid any false positives that may be produced from food or beverages. See more below on eating carbs and testing.

It is important to note that mouthwash and toothpaste as well as medications such as inhalers or strong cleaning agents can also produce false positive readings on the Tone.

Q: How do I know what numbers mean I am burning my body fat?!

Due to the lack of scientific research to date, there is no scientifically established range of breath acetone ketones that define ketosis. There is also a lot of interpersonal variability when it comes to acetone ranges.

When first getting the Tone, testing every morning before eating or drinking will establish your baseline of acetone. To figure out your individual ranges for ketosis and deep fat burning it is recommended to do one of these two approaches:

1) Doing a fasted day (24 hour fast) and testing during and at the end of that fasting period. This will establish your personal range of numbers for what your breath ketones are in deep fat burning and ketosis.

It is relatively easy to do if you are already keto or fat adapted- one can eat dinner and then fast overnight and skip the first meal, breaking a fast with dinner the next day. Testing may be done anytime during that fast but the last test before breaking the fast should show you what your personal range is for deep ketosis and deepest fat burning.

2) Taking exogenous ketones in the form of commercially available ketone salts or ethers, MCT oil or MCT oil powder. Testing hourly and recording all of the readings including the peak numbers. This will indicate the breath acetone ranges that mean you are burning body fat and also in deep ketosis. Your body will not burn your own body fat during this time, however it will burn the fat and ketones consumed, and through this upregulated fat burning we can see the breath acetone ranges that mean you are personally in your deepest lipid oxidation or fat burning.

Unlike blood ketones or BHB, which have been established at 0.5 mmol as the start of deep ketosis or fat burning, there is currently no established definition of ketosis with breath acetone measuring, partly due to fact that there is a lot of interpersonal variability when it comes to breath ketone expression.

Many factors influence our levels of breath ketones and blood ketones and the ratio of how much is produced and how much of oxidized or burned for fuel. (The factors include the redox potential of our mitochondria, liver energy status, glycogen levels, activity levels, level of keto adaptation and more)

By establishing what ranges you personally see when you are in deep ketosis using the above methods, you will know what your personal ranges look like for deeper fat burning which is guaranteed after a day of fasting.

Make sure to stay well hydrated with lightly salted water or bone broth and electrolytes during your fasting period.

Q: What does the Tone device measure?

A: The Tone device measures breath acetone which is one of the three ketone bodies produced during fat oxidation (fat burning).

Q: What does breath acetone indicate?

Elevated levels of breath acetone indicate that the body has switched from being primarily fueled from glucose to being primarily fueled from fat and ketones. As the body mobilizes fatty acids from stored body fat to be burned for energy, breath acetone rises as a by product of ketones being made.

The liver begins to make ketones from fatty acids into acetoacetate (AcAc), which can then be converted into BHB, the stable, storage form of ketone that we measure in the blood, or it can directly oxidize the AcAc for fuel. When the AcAc is burned for fuel, it is converted into Acetyl Coa and used to make ATP. (see the illustration below for a visual of this process)

As AcAc is a less stable form of ketone, approximately 20% of it will be spontaneously decarboxylated to acetone, which you can think of as a byproduct of burning fat for energy. Ketones are made from fat, so when you burn the ketones for energy you are burning fat for energy. This is why breath ketones are a direct indicator of fat oxidation or fat burning.

Q: Why do I have low readings on the Tone?

A: There is a lot of interpersonal variability on the Tone. It can take time to see an increase in breath ketones depending on how large your glycogen storage is and the energy status of your liver, it very individual.

Taking a measurement on the Tone after a 24 hrs water fast is a good way to determine your deep ketosis and deepest fat burning numbers for yourself for breath acetone.

Q: Why measure acetone instead of blood ketones?

A: Bleeding and finger pricking and expensive test strips aside, breath measurements of acetone give us a true indication of the utilization of fat for fuel.

When we test blood ketones, we are testing BHB which is a storage form of ketone. The liver first makes the acetoacetate (AcAc) and converts it into BHB when storing energy. In order for the BHB to be oxidized or burned for fuel, it needs to first be converted back to acetoacetate (AcAc). When AcAc is then used for fuel, a portion (20%) of it degrades to acetone which can be measured on the breath.

The blood capillary measurements of BHB are only providing feedback on half the picture: how many ketones have been stored and are available in the blood, they do not tell us how much AcAc has been made and how much is actually being oxidized for fuel. Acetone on the other hand indicates what has been oxidized for fuel as acetone is a by product of that AcAc being used for fuel.

Over time people who are keto adapted produce less BHB because the body is so adapted to directly burning AcAc that it does not need to make the storage form to the same degree; unless a person either is eating excess dietary fat for their requirements in which case energy needs to be converted to BHB for storage, or if metabolic demand increases from a situation such as extended fasting (beyond 24 hours). This is all dependent on the redox potential which is the ratio of NAD+ to NADH in the mitochondria.

See this study by Virta which shows how peoples BHB levels went from 0.1 mmol up to 0.5 and then declined down to 0.3 over a year of being keto adapted:

In fact, as many people know, once we fully go from glucose of fat adapted to keto adapted, we stop excreting AcAc in the urine, because the body has up-regulated the mechanisms to oxidize AcAc, which is why urine test stips are not a precise or useful measure of ketosis or fat oxidation.

For these reasons, research has also shown that the acetone may actually be used as a proxy for blood glucose. This study examined the correlation of blood glucose and breath acetone and showed it is inversely correlated with a coefficient of 0.52.

Correlation of breath acetone levels with blood glucose collected from different subjects on their fasting days:

Source: Prabhakar A, Quach A, Wang D, Zhang H, Terrera M, et al. (2014) Breath Acetone as Biomarker for Lipid Oxidation and Early Ketone Detection

Q: Can I use the acetone measurements instead of pricking my finger to check blood glucose?

A: As acetone has been found to be inversely correlated with blood glucose, if you are wanting to use acetone measurements they may serve as a proxy for blood glucose measurements if the goal is weight management which has been shown in peer reviewed research to be associated with overall wellbeing.

This would not be appropriate at anytime for any kind of diabetic monitoring of glucose and the Tone is only a wellness device and as such it is not an approved medical or clinical grade device for the use of monitoring any kind of health condition.

Q: Do I need a caloric deficit to lose body fat?

Yes. In order to lose body fat, you do need an energy deficit.

Regardless, even if not in a calorie deficit (needed for fat loss) you are still in ketosis, burning fat (dietary fat), and experiencing the many benefits of nutritional ketosis.

Being in a calorie deficit while adhering to a ketogenic diet is common and further increases ketone production and fat loss.

Q: Do I need to do a keto diet use the Tone?

A: Although it is possible to get ketones as a by product of fat burning it is recommended to follow a ketogenic diet or be doing fasting for best results using the Tone device. The Tone is not intended for use with a high carb diet or with carb meals. Carbohydrates in meals produce high levels of both CO2 and methane due to the fermentation of these foods in the gastrointestinal tract by gut bacteria, which can produce false positives on the Tone device.

Q: Do I need to do a keto diet to have ketones?

A: The answer is no, you just need a caloric deficit to augment levels of fat oxidation levels. This study here demonstrated that it is caloric restriction that generates ketosis, not just following the traditional ketogenic macros. In the study induced ketosis in individuals doing 1,000 calories of carb per day. This is counter to theory of what triggers ketosis is the that low insulin and liver glycogen depletion triggers the onset of ketogenesis. Fasting, caloric restriction via intermittent fasting, PSMF, and eucaloric ketogenic diets can generate ketones and are all recognized in the scientific literature as such.

That being said, for best results the Tone should be used in a fasted or keto diet context as these will be optimal for the generation of ketone bodies from lipid oxidation or fat burning.

For an individual who is following a ketogenic diet, the results on the Tone are will be from the acetone registered.

Individuals who follow a high carbohydrate diet wI’ll mostly likely get a false positive reading on the Tone from CO2 and methane.

There is a condition known as Small Intestinal Bacterial Overgrowth (SIBO). It is defined as the presence of higher amounts of bacteria in the small intestine. Methane can be produced by bacteria in the small intestine after eating carbohydrates. If an individual has a healthy gut microbiome without overgrowth of bacteria in the small intestine, they do not produce or exhale methane in their breath.

The potential influence of the methane from the bacteria is minimal, if any at all, when on a low carb diet.

For this reason, it is recommended to only test with the Tone in the morning before any food or drink and using this data as the main measure to detect lipid oxidation or fat burning to avoid any potentially false positives.

This paper details SIBO and breath methane detection a bit more.

Q: Do you need to follow a keto diet to use the Tone?

A: The Tone device is not intended for use for those following a high carb diet or doing carb meals; it is recommended to follow a very low carb diet or a dietary strategy that induces ketones from fat burning such as keto or fasting with a caloric deficit. In general it is best to test with the Tone once per day, first thing in the morning before food or drink.

Q: I ate a high carb meal, why did I get a high reading on the Tone?

A: Individuals who follow a high carbohydrate diet may get a false positive reading on the Tone from both CO2 and methane. These breath gases are produced from the breakdown of carbohydrates. Some carb foods also contain specific sugars in them such as raffinose in cabbage which can produce very high readings on the Tone device but are not breath ketones.

The potential influence of the methane from the bacteria is minimal, if any at all, when on a keto diet.

For this reason, if an individual is on a high carb diet, it is recommended to not use the Tone device or only test with the Tone when fasting and using this data as the main measure to detect lipid oxidation or fat burning to avoid any potentially false positives.

See the question above for more.

Q: What do the numbers mean on the Tone, and where should I be?

A: The Tone analyzes the concentration of breath acetone on your breath. It gives you feedback on how much acetone, which is a ketone, is being diffused through your airways, after being converted first from fatty acids, to acetoacetate and BHB, the two other forms of ketones. In the scientific literature, acetone has been found to be a biomarker for fat loss, as it is expressed when the body is burning fat for fuel. The numbers on the Tone Device represent concentrations of acetone from zero, representing no ketones present and therefore no fat burning detected, to light fat burning and the fat burning zone. To find YOUR personal range for deep fat burning and ketosis, see Question 1 above.

If your goal is to burn fat for fuel, being in "Light Fat Burning" or the "Fat Burning Zone" will let you know that you are burning fat for fuel. Following a ketogenic diet where carbohydrates are restricted will shift the body into being fat adapted, whereby it is predominantly burning fat for fuel. Carbohydrate restriction and energy deficits both generate fat burning in the body.

Q: What range should I be in?

A: The optimal range for fat burning starts at around 4-5, indicating a light state of ketosis or fat burning. Results of 9+ indicate that the body is very likely predominantly burning fat for fuel, indicating a higher level of ketone production from fatty acids. To find YOUR personal range for deep fat burning and ketosis, see Question 1 above.

The Tone Device is a wellness device and as such the feedback from it is meant to provide guidance on which meals, foods, activities, intermittent fasting, exercise and dietary protocols put the body in a greater or lesser state of fat burning.

Q: I often get a "4" on the Tone. What does this mean?

A: A "4" indicates someone is between no ketosis and the start of ketosis. It can indicate light fat burning. Readings of 5 and above have been shown to correlate with the start of nutritional ketosis, when the body starts making ketones from stored body fat.

Once you get the TONE, it is important to test on a regular basis throughout the day either whilst doing a keto diet or fasting so that you can establish your baseline. This is where the fun begins as you can start to test different carb levels, protein amounts, macros, caloric intakes, intermittent fasting windows and exercise and see what makes the numbers go higher.

Q: I get a "0" when breathing into the device. What does this mean?

A: A reading of "0" with no beep sounds indicates that no ketones (acetone) were detected on the breath. This is not a bad thing, it just means that you may need to decrease carbohydrate intake in order to boost your ketones and fat burning.

Q: My first blow on the Tone will be a 24 or 22 which I feel like is super high then I test again right after and it’s a 10 or 9? Am I doing something wrong?

A: Not at all! It’s best to wait about 25-30 minutes between testing again. All the acetone accumulates at the boot on of your lungs, so when you test, you breathe them all out when you blow again it should be near zero to a third of the first reading.

Q: I often see the same number repeated on the Tone. Is it defective?

A: It is actually more common than not to see the same number often. The body keeps levels in very tight ranges especially ketones which have a negative feedback loop in order to prevent excessive acidity from uncontrolled ketone production. This negative feedback loop sets ketones in a very tight range unless you are deliberately changing up your routines to deepen fat burning or ketosis.

Acetone is a very volatile compound and the Tone is measuring in parts per million, so you are getting an approximate value of these parts per million and at the lower ranges, the numbers will be more of a "ballpark" indicator of where acetone is, at the higher ranges such as fasting for 16 hours or more, the numbers tend to become more and more specific as each hour goes by and acetone ketones go higher and higher.

If you get a specific number repeatedly, you may calibrate the Tone by turning it on without breathing into it and letting it read 0 three times. This will warm up the sensor a little more as well to help with the accuracy at lower levels of ketones.

Because the body keeps levels in such tight ranges and is always adapting to your caloric intake, changing things up is helpful! Experimenting with longer intermittent fasting windows, different exercises, doing a longer intermittent fast than your typical routine or cleaner intermittent fast (only water and black coffee, no sweeteners or creamers or chewing gum outside your eating window, etc) can generate higher ketones and greater lipid oxidation or fat burning.

Q: When should I be testing? How often?

I recommend testing in the morning before consuming any food or drink, or brushing your teeth. Mouthwash, medications such as inhalers, and other substances can conflate the numbers on the Tone.

Once you get the Tone, it is important to test on a regular basis while fasted so that you can establish your baseline. This is where the fun begins as you can start to test different carb levels, protein amounts, macros, caloric intakes, intermittent fasting windows and exercise and see what makes the numbers go higher. Testing frequently while fasted especially during a 24 hour fast from after dinner to dinner the next day will give you a good idea of your daily range and then your numbers when in deepest fat burning.

Q: How do I calibrate the Tone?

A: From time to time you can re-calibrate or reset the Tone.

How to calibrate the Tone Device:

First, turn the Tone on, wait 20 seconds then when it says “blow” then press the multifunction button twice to access the memory. Then double tap it again to return to testing mode and repeat the process one more time. This will allow the sensor to warm up for 60+ seconds and reset.

Finally, do a test, and then see what number it shows.

Q: Why do my numbers on the Tone go down after exercise or after intermittent fasting?

A: Testing breath ketones with acetone is different than blood ketones with BHB because acetone is volatile. When we exercise, we are placing a huge demands for fuel on the body - in the absence of carbs, the body has to rapidly make ketones to use as a replacement for Acetyl CoA. For this reason, more acetoacetate is being converted directly to Acetyl CoA and oxidized for fuel so less acetoacetate is available in circulation to be decarboxylated into acetone.

When the burn rate for ketones goes up rapidly, the body is utilizing so much for energy directly that there is less left to be converted to acetoacetate and then to acetone. Usually ketones go back up, sometimes higher than before the exercise, 3-4 hours following a workout as the body switches back into a lower grade metabolic demand.

Similarly with regards to intermittent fasting, people are often surprised to see their breath ketones initially dip instead of go up as they see with blood ketones. The demand for energy is so high that the acetoacetate ketones are oxidized very rapidly for fuel that they are not available as available in circulation to spontaneously degrade to acetone.

For a deeper explanation, listen to to this podcast episode here: Understanding Ketones, Ketone and Blood Glucose Testing to Hack Your Metabolic Health

Q: I drank some alcohol and the device blew a very high number. Is this normal?

A: Alcohol can inflate the numbers on the Tone. It is recommended to avoid using the Tone during and right after drinking alcohol.

Q: My breath ketones did not match my blood ketones. Is this normal?

Yes. The current research shows that breath ketones have a correlation of about 0.57. The ratio of BHB to Acetoacetate anext then breath acetone is different for each individual. It depends on the redox potential (ratio of NAD+ ti NADH) of the mitochondria as well as the energy state of the liver.

When there is a lot of fuel in circulation such as blood glucose and/or fats, our NAD+ levels are lower abs therefore more BHB blood ketones are produced from Acetoacetate. When our blood circulation is low in energy, NAD+ levels go up and we make more Acetoacetate which is then degraded to acetone. This means breath ketones are higher.

When ketones are being made and stored in a stable form, BHB ketones are being made from acetoacetate (AcAc). When ketones are being utilized for fuel, the AcAc form is being used for fuel and acetone is spontaneously degraded from those acetoacetate ketones.

AcAc ketones are generated in the liver from fatty acids to make Acetyl-CoA. The fatty acids are then converted to Acetoacetate (AcAc) and then to BHB (Blood ketones). AcAc then spontaneously converted to acetone and is diffused into the airways. This is how we can measure it on the breath.

Higher levels of breath acetone indicate higher levels of ketones being generated, however they also give us a fuller picture of ketone utilization and "fat burning” or fat oxidation as higher acetone levels come from higher acetoacetate levels which come from fatty acids being broken down. BHB levels in the blood show a lot of ketone fuel stored and available but in the case of someone wanting to burn body fat, it is not ideal to have high BHB but rather high acetone which indicates efficient ketone utilization.

Having BHB levels that are the same as breath ketone levels is only expected when someone is either not in a caloric deficit (eating at maintenance or eucaloric intake), eating in a surplus, or during extended fasting.

Otherwise if someone is in a caloric deficit for fat loss purposes, BHB will decouple from acetone as energy is being used for fuel and not stored. Thus, acetone should be detectable as AcAc is being oxidized for fuel.

Source: Suntrup Iii DJ, Ratto TV, Ratto M, McCarter JP. Characterization of a high-resolution breath acetone meter for ketosis monitoring. PeerJ. 2020;8:e9969. Published 2020 Sep 24. doi:10.7717/peerj.9969

The correlation between breath and blood ketones is R2=057. Here is a chart to illustrate. As you can see, breath and blood can be exactly the same at times, and at other times, breath can be 20 parts per million (ppm) and blood is 0.9:

Here is the time lag illustrated, which shows that peak breath ketones lag behind peak blood ketones, which makes sense as blood ketones are first formed and then later diffused into the lungs and expelled in the breath:

Source: Suntrup Iii DJ, Ratto TV, Ratto M, McCarter JP. Characterization of a high-resolution breath acetone meter for ketosis monitoring. PeerJ. 2020;8:e9969. Published 2020 Sep 24. doi:10.7717/peerj.9969

Q: How long after you eat a meal should you test?

A: Food and beverages can conflate the readings on the Tone. Due to this and to the time lag, you should wait at least 3-4 hours after a meal to see a difference in your ketones as compared with your pre meal test.

Q: Can people who do not do keto or low carb also have ketones showing on their breath?

A: Yes, if they are in a caloric deficit or fasting. Acetone is a biomarker for fat loss, so if someone is dieting they can see ketones on their breath. This has been proven in research studies.

Other reasons could be related to drinking alcohol, using mouthwash, or taking medications.

For a more explanation please listen to this podcast episode:

Understanding Ketones, Ketone and Blood Glucose Testing to Hack Your Metabolic Health

Q: My device shows "Charging" for a long time and only shows the battery 3/4 full. When do I know it is charged?

A: The device is charged when the screen stops flashing the "Charging" screen. The battery life is quite long and will not require another charge for 1-2 weeks at a time.

Q: Can I travel by airplane with the Tone?

A: Always consult the safety requirements of your airline before travelling with the Tone. The Tone contains rechargeable lithium ion battery. Most airlines allow personal electronic devices in the cabin only. The device must be turned off and not used during the flight. It must be carried in a travel case that prevents it from accidentally turning on during travel. See more requirements here on the FAA website:

“You can carry your device on a plane. Keep it in the cabin, but no use allowed! Learn more from FAA on how to safely pack your for air travel. #PackSafe www.faa.gov/go/packsafe”