Keyto Review: eliminate Keto confusion with just 1 breath

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Keyto Review: Keto is a great way to lose weight, but it can be hard to know if you’re on the right track. The Keyto Breath Sensor analyzes your breath to tell you if you are burning fat or sugar for energy. It eliminates confusion on if you are on the right track and is clinically proven to be 3x more effective than Weight Watchers! In this Keyto Review, we’ll tell you all about the Keyto Breath Sensor.

Must Have Keto Device
Keyto Breath Sensor

Eliminate keto confusion with just one breath. The Keyto Breath Sensor allows you to find out EXACTLY where you fall in ketosis and stop you from stalling out.

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It’s backed by over a decade of science, Keyto offers a new perspective on keto. In just one breath, Keyto breaks down everything into an easy-to-understand keyto level so you know exactly where you are in relation to their Keto diet. Their breath sensor eliminates confusion by telling you, for certain, if you are in Ketosis or not.

Keyto Review

About me and the Keto Diet

The 4-Hour Body

This is the book that changed it all for me. It introduced me to the keto diet and a whole lot more!

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03/17/2024 06:01 am GMT

I’ve been on the Keto Diet for more than 8 years, way before it was cool. It all started with reading the 4 Hour Body and was introduced to the “slow carb” diet. The slow carb diet isn’t technically keto, but it was a simple stepping stone to Keto.

Basically, think of slow carb diet as keto + more beans and legumes. I did the slow carb diet (in addition to the cheat days), for about 1-2 years before I hit a plateau and decided to go full Keto.

Slow carb diet = keto + legumes/beans.

If you aren’t familiar with the Keto diet, it’s pretty simple.

Keto is a diet where you eat a lot of fat and protein and very little carbs. You want to eat food that is low in carbs so your body can use ketones for energy. Technically, you are focused on NET Carbs, which is the pretty simple equation of:

Carbs – Fiber – Sugar Alcohols = Net Carbs

Most folks try and keep their net carbs down to 20 – 40 Net Carbs.

The goal of ketosis

Ketosis, the ultimate goal of the keto diet, is a way for your body to use ketones for energy. If you are in ketosis, your body turns to fat to burn as an energy source.

Your liver turns this fat into ketones, a type of acid, and sends them into your bloodstream. Your muscles and other tissues can then use them for fuel. If you are eating a bunch of carbs and sugar, your body will use that for fuel first – not dipping into your fat reserves (which face it, we all have).

How do you know if you are in ketosis?

It can be hard to know if you’re REALLY in ketosis!

Even if you are measuring your net carbs, it can be tough to know if are REALLY in ketosis. Previously, the only way to know was through a painful blood test or to urine test by peeing on urine strips. That brings us to the keyto device.

What is the Keyto Breath Sensor?

Keyto Review: This little device is pretty might!

This little keyto device looks a bit like a skinny vape pen. But it’s not that at all. It’s a magical acetone measurement device that accurately measures your ketone levels and if you are REALLY in ketosis.

After you connect the Keyto to your smartphone (Apple or Android), getting an accurate measurement is simply straightforward:

  1. Power on your Keyto device – there’s literally only one button on it!
  2. Open the Keyto App on your iPhone on Android
  3. Select log a Keto level
  4. Wait for the meter to reach 100% (it takes about a minute or so)
  5. Breath normally and breath into the device.

It literarily takes one breath and the Keyto App gives you real time feedback on your Keto level. After you breathe into the device, it takes a couple of seconds and gives you one of the 6 levels of Keto you are in:

What each Keyto Level means for your weight loss and health goals.

Level 1-3: You’re utilizing carbohydrates for energy. To enhance your level, limit carbohydrates and sugar use.

Level 4: You’re in light ketosis, and you’re burning fat for energy. This is a healthy level to be in, and you will notice benefits.

Level 5-6: You’re in absolute ketosis and relying mostly on fat for energy. These are the best levels to be at (achieving level 6+ is not essential).

Carbs – Fiber – Sugar Alcohols = Net Carbs: You’re in really deep ketosis. This could be achieved through lengthy adaptation to the diet or fasting. Genetics also has a role!

How accurate is the Keyto Device?

I thought my device was broken when I got it, honestly!

To be honest with you – I first thought the Keyto was broken when I got it. I thought, for sure, I’d be in ketosis right away.

It turns out “cheating” just a little on the diet will produce profound differences in your ketone levels. I was shocked.

It doesn’t take much to knock you out of Ketosis at all. In fact, just a couple of jelly beans or a little sweet treat will lower you down to level 1 or 2 pretty easily. This is especially true if you are eating other foods, like Low Carb Tortillas, that do have some carbs in them. Even at 4 Net Carbs, a quesadilla easily has 8+ net carbs (two tortillas). Add in some other low-carb candy, for example, and you can be above 20 grams of net carbs without thinking about it.

I didn’t do blood tests or anything to MAKE sure the Keyto was accurate. But it is incredibly sensitive!

Does it the Keyto Device work for weight loss?

The Keyto Device isn’t magical, it’s not going to make you lose weight simply by breathing into it. However, I was SHOCKED to read that 98% of device users in their trial lost weight. That’s pretty amazing.

As I always say, the best diet is something you can stick to, it doesn’t matter if it’s keto or something else.

Why I love the Keyto Device + Keyto App

I’ve tried some of the other options and none of them worked for me. Let me explain the pros and cons of the blood or urine test and other options, too (besides using bodily fluids for measurement).

Doing nothing

After doing keto for a while, it’s easy to wing it. But it’s also really easy to get off course, too. If you start to get too comfortable or feel like you’ve got it all figured out – it’s easy to slide.

To be honest, I was being a little too liberal with non-keto treats (just a bite of cake here or there) and keto substitutes (that still added up to a decent number of carbs) and I started to gain a couple of pounds.

It’s great to have an easy way to see if you are on track or not, for real.

Pee Stips

To be honest, I’ve tried the keto urinalysis strips (AKA pee strips or keto strips), but they are messy (you have to pee on them, after all).

Besides being super messy, they are also a bit hard to get a firm number on. Are you the 1st darkest color or the 2nd? It’s all up to the eye on what level of ketosis you are in and how long you let it sit.

These never worked for me.

Blood Test

To be 100% honest, I’ve never tried a Keto blood test, but they are more accurate. Once again, they are also messier and require prep and clean-up. No Bueno.


I’ve also tried lumen multiple times (read our Lumen Review). In that review, we mention that it is not for people that are on Keto. It’s really tough to follow their program AND be keto – as their program has you eating carbs sometimes to improve what they call your “metabolic flexibility.”

Nothing wrong with it, but it’s just not for people trying to stay on the keto diet.

Lumen vs. Keyto: Which one is better?

The main difference between Lumen and Keyto is what they are measuring. The Keyto device is trying to get – and keep – you in ketosis for fat loss, while the Lumen is focused on “Metabolic Flexibility.” Either one will help you lose weight, but Keyto is focused on helping you lose weight from the Ketogenic Diet.

Keyto Device + why it’s different

As I mentioned, I thought that the Keyto was broken the first time I tried it. I thought, for sure I’m in ketosis. And I wasn’t.

The Keyto breath sensor works a little bit differently than the urinalysis strips or blood testing.

How Keyto works

The Keyto device is a sensor that detects acetone levels in your breath. This is a biomarker for ketosis, which means that it can tell if you are in ketosis or not. Acetone is produced when the liver breaks down fatty acids into energy.

This happens when there is an excess of acetyl-CoA from fatty acids, which can happen when you are on a ketogenic diet or when blood sugar levels are low. When the Keyto device detects acetone in your breath, it can tell how well your body is using fat for energy and whether you are in ketosis or not.

Every Keyto has a special gas sensor that is only for acetone. It can tell how much acetone is in your breath. The metal oxide in the sensor is arranged in nanoparticles so it can measure how much acetone is in the air. This happens when the sensor gets really hot – over 400 degrees Celsius. The heating element makes sure the sensor is hot enough to work well.

How the sensor works

The surfaces of the metal oxide nanoparticles in the Keyto sensor react with oxygen from the air and reducing gases such as acetone, resulting in conductivity changes that can be measured by our readout electronics.

The level of conductivity change produced during a breath measurement is turned into a digital signal. This digital signal is received by a microcontroller, and transmitted to the app via Bluetooth. Through an algorithm derived from machine learning techniques, the app then converts the digital signal into Keyto Level.

Through extensive research and development and decades of experience with gas sensors, Keyto has found a metal element and oxide combination with remarkable properties that make their sensor selectively reactive to acetone (and not other volatile compounds).

How do they know this all works?

Researchers have studied the relationship between breath acetone and fat loss for a long time. Studies have consistently found that people lose weight and fat as their breath acetone levels increase.

How much weight someone loses depends on many factors, like starting weight and how long the person maintains the higher breath acetone levels. But researchers found that if you keep your breath acetone level at ~2 ppm for a week, you’ll burn about half a pound of body fat. You can achieve these results by eating fewer calories.

What we don’t love about Keyto

Nothing is perfect right? But there are a couple of small things we didn’t care for with the Keyto sensor.

Long startup time

Keyto Review: seems to take a LONG time to start up.

I know it’s a bit unfair to say that something heating up to 400 degrees celsius is taking too long, but sometimes it just does take too long to warm up, it feels like. It’s just a few minutes at the longest (obviously takes longer if the sensor is cool and it’s been stored in a cool room, but just a few minutes isn’t the worst tradeoff for getting your keyto score.

It really isn’t the worst thing in the world from a single AAA battery.

Trying to do a lot

I know it’s tough to please everyone, but as we read other reviews and were testing this product for ourselves, it’s tough to realize that everyone is on a different part of their journey.

Some people need meal plans. Some people need personalized coaching. Some people need the things offered in Keyto Premium. Some people even need personalized meal plans full of low carb food for the ketogenic diet – but that’s just not where I am at now.

Overall, Keyto has done a great job catering to all the different needs – from the newbie on the ketogenic diet to someone that just wants to know their current level of ketosis (me).

Alcohol confuses Keyto

Don’t depend on the Keyto measurement after you’ve had a hard seltzer (or two). Even a couple of sips, in my experience, will give you an incredibly elevated score.

It will get back to normal by the next day, but take a measurement before drinking anything if you want an accurate score.

Keyto Review: Who it’s for

This is easy. I’d say the Keyto is designed for two unique sets of people.

People who have been on keto for a while

That’s me. I love having access to a device that can tell me exactly what level of ketosis I’m in right now. It’s easy to cheat, but it’s also easy to get back on track.

I don’t need a meal plan to show me low carb foods I can eat, I know what they are and what they aren’t. I just don’t want to stall my progress and know my ketosis level. That’s it.

People wanting to start the ketogenic diet

If you are new to the ketogenic diet and have no idea where to start, Keyto is actually a really good place to start.

The keto diet can be overwhelming and the keyto premium offerings do a lot more than tell you the acetone in your breath levels.

It does take a few weeks to start to see progress, but after you get over the dreaded keto flu, I promise you’ll never feel better in your life.

The Keyto app, which is also available for iOS and Android devices, includes shopping lists, meal plans, and recipes in addition to the Keyto course and food database. They also created a full set of audio podcasts that teach users about essential topics and practical advice to starting out.

Keyto Breath Sensor Review: Final Verdict

We Tried It Approved Keto Device!
Keyto Breath Sensor

Eliminate keto confusion with just one breath. The Keyto Breath Sensor allows you to find out EXACTLY where you fall in ketosis and stop you from stalling out.

Buy Now
We might earn a commission if you make a purchase, at no additional cost to you.

After testing out lumen, I was looking for a keto-focused alternative to pee strips. Seriously, it’s just gross if you think about it.

If you are serious about your health and want to finally get it under control, then check out Keyto. It’s clinically proven to be 3x more effective than Weight Watchers and 98% of device users in their trial lost weight.

Why? It simply eliminates confusion.

No more counting calories or thinking, “is this 1 serving or 2?” Follow the program, take your measurements and find out if you are going to lose weight or not by taking an honest measurement.

Want to find more of our awesome keto content? Check out our Perfect Keto Review, our Perfect Keto Promo Code, our Genius Gourmet Review, the best Keto Jerky and the best Keto Snacks on Amazon!

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