Listen, this post is going to make me seem like the world’s biggest hypocrite. After writing about gradually turning vegan last week, I’m doing a full 180 to write about how I spent this past week piling up meat and heavy cream to go on a keto diet.

In my defense, it was to try out the Keyto, a breathalyzer and mobile app that tells you when your body is in ketosis — the state where your body burns fat for fuel. As someone who has struggled with his weight for most of his adult life, the opportunity to get paid to shed a few pounds (by doing my job, no consideration changed hands with Keyto) was too good to pass up.

We wrote up the Keyto back in November, when the company raised $2.5 million and launched an Indiegogo campaign (where it raised another $1M). The good news is that unlike so many other crowdfunded hardware devices, there is an actual device that I actually used, and the company says it is shipping the first batch to early backers (who paid $99, the device will retail for $179) this coming week.

As a refresher, the Keyto is roughly the size of a vape pen. After you start your keto diet (very few net carbs, lots of fats), you blow into the device three times a day. The Keyto measures your breath for acetone, a by-product that your body makes when going through ketosis.

The Keyto talks to the accompanying app on your phone which calculates your “Keyto Level.” A level of 1 – 3 means your body is still using carbs for energy, 4 means you’re in “light ketosis” and your body is using fat for fuel, 5 – 7 means you’re in full ketosis and using mainly fat for fuel, and level 8 is “Deep Ketosis” which I think rips open the space/time continuum, allowing you to travel back in time and inhabit your 22-year-old body.

In addition to rating your ketosis level, the Keyto app also provides food recommendations. There’s a quick list of foods to eat and avoid, as well as recipes and meal plans. The app also has a community feature and some general advice about following the keto diet.

So. How well did it work?

Before we go any further I should say that I am not a nutritionist, do not advocate the keto diet for everyone, and suggest you consult with your doctor before making any changes to your diet.

Having said that, first, let’s talk about the device. The box comes with the main breathalyzer, four mouthpieces, a battery and a travel bag. The Keyto itself feels solid and is easy to self-assemble. My one issue with the build is that the button you push to turn on the device sinks below the line of the rest of the device, so it feels “stuck” when it’s not. It’s not a big thing, but it cheapens the feel of the product.

The app is still in beta, so I had to get a special link to load it onto my phone. Installation and registration were easy and I could get up and running with my first Keyto breath check in just a few minutes. The app looks fine and is easy to figure out, but it’s pretty dull. We’re living in a golden age of app design and Keyto’s boxy UI feels hobbled together.

Oddly, the instructions for blowing into the device were surprisingly complex. The app counts you down to get you ready to blow (but don’t inhale too deep!). When you do blow the app starts by saying “Blow powerfully” and then almost immediately it says “Blow normally.” Which is it? And how does it impact my score? A company rep told me that it doesn’t really matter as long as you blow till the end of your breath, where most of the acetone will register.

I spent last Sunday pigging out on cakes and ice cream, knowing that I’d be giving them up the next day. I did my first breath test in the midst of that sugar rush and sure enough, I blew a 2: my body was still using carbs for energy.

With that carb caravan was behind me, I became pretty strict about being on keto. I haven’t had a slice of bread or piece of candy since that Sunday. The general food guidelines offered by the Keyto app were actually quite helpful (especially if you love avocados), and provided me with enough food variety to where I didn’t feel bored by being on this diet.

By the end of Tuesday, I had blown my first 4 — light ketosis! I had broken though a barrier, and it was enough to keep me going. Then on Thursday I blew a 5 – full ketosis. Jackpot! Now I was addicted and started blowing into the Keyto more than three times a day. It was a game, and I wanted to win.

To be honest, it’s become such a game that I stopped and blew once while writing this post (I got a 6).

Now would be a good time to say that I have no way to verify the Keyto’s results here at home. I could go get a blood or urine test, but I can’t do that every day (let alone multiple times a day). From a product review perspective, the device seems to work as advertised. You blow into it, it gives you a score. The longer you adhere to the keto diet, the higher your score goes. Whether or not that score is entirely accurate, I can’t say.

I can also see how this gamification could get extreme and possibly unhealthy. I became obsessed with my Keyto score, checking it more than three times a day (see above) and trimming away anything that might lower it. I wanted to win. Win what, exactly, I wasn’t sure, but I certainly don’t want it to come at the expense of my overall health.

This has been a good experiment, and the Keyto made cutting out processed sweets and constant snacking easier than writing what I eat in a food journal. But now that I’ve blown it out, I’m ready for moderation–and to bring back those vegan treats.

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  1. I have received mine and paired up and did a reading on it with no problem. However, on the third time I tried, the luck was gone, and the keyto device only paired again after I turned my phone down. This finicky behavior continued, culminating today where the app told me “Unable to log” and to contact customer service. This is frustrating.

    Finally, the start button is among the flimsiest I have seen – I am wondering how long it will last.

    Overall I am not too happy by how crappy this seems to be built – you are nice to only complain that the button seemed stuck. It just does not work!! After two days!!! Might be a good idea but execution …. meh.

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