Weight loss tracker duo monitors O2 levels for exercise needs
A duo of devices is being developed by Path, which the company claims can help users lose weight according to their metabolism. The devices could be used to test oxygen and CO2 levels once a month and suggest an exercise plan to burn the amount of fat required for a specific weight goal. Users breathe into the Path Breath, which is roughly the size of a lighter, and the wrist Fat Band tracks active minutes with an accelerometer and an optical heart rate sensor.

What if you could breathe into a device no larger than a cigarette lighter, and that was enough to know how much exercise you needed in order to burn fat?

That's the dream the Path Breath and Fat Band are promising, a duo of devices built to gauge how you can best lose weight according to your metabolism. There's no step counting, no sleep tracking; just a total focus on shedding pounds, using your oxygen and CO2 levels to tell you how much exercise you need to do in order to lose x amount of weight.

Many people pick up a fitness tracker with the specific intent of losing weight, and while we know that spending a day moving around is better for us than a day on the couch, most of the time our wearables are relying on algorithms to guess how well we're doing. Specifically targeting your metabolism sounds like it could help you shed the pounds more quickly, but does the science agree?

Path founder Gaurav Shukla assures me that it has drawn on the expertise of a number of brains in this field alongside its own lab research, but there is certainly some debate over the extent of variation in people's metabolisms.

However Path believes that by taking a breath reading once a month it can lay out an exercise plan that will help you effectively burn fat – although obviously you need to be keeping an eye on your calorie intake too.

Path has essentially shrunk the tech you'd find in a VO2 Max device, replacing the mechanical turbine with a small flow sensor and an amperometric sensor instead of an electrochemical one. "We miniaturised it and built an AI on top of it so we could know how someone was burning throughout the day without them having to keep it in their mouth," Gaurav tells us.

By taking one reading over a five-minute period, in theory the Breath will be able to tell you exactly how your body burns fat for the rest of the month. So if you're planning to lose five pounds over that period but your body isn't built to do so, you're going to hear about it – and then adjust your goals accordingly.

The wrist band, meanwhile, tracks your active minutes. Although the prototype we tried wasn't working, it was close to what the final design will be, and it's notably light and comfortable to wear. Aside from the small LED there are no telltale signs of any tech, but inside is an accelerometer and an optical heart rate sensor. The app will tell you how much you need to run or walk each day to burn a certain amount of weight, and the band will monitor your activity and any workouts you do.

Both the band and breathing cylinder come with a wireless quick-charge dock, but a full charge cycle of the band will only last 24 hours. Gaurav says this is because it is taking a lot more data points than many other trackers. "We are collecting your breath by breath data. That means a lot of power."



So you might not wear it in bed, but while sleep data is good it's not all that accurate for fat burning, according Gaurav. Besides, you're going to be stagnant during the time; Gaurav says that with the analysis Path can still predict your fat burn "with almost 95% accuracy".

In fact, you wouldn't even need to keep it on all through the day: if the AI is smart enough to learn everything about your rate of metabolism, and your activity is not changing dramatically, it should be able to project reasonably well.

"If you're only focusing on fat burn, you don't need to wear it all day," says Gaurav. "Maybe you wear it for the 10 minutes of exercise because that's when your aerobic shift is happening. There's no way that in a three hour period your body is going to have a dramatic shift."

Path is running a Kickstarter campaign for the project, and it's already passed its $30,000 goal, currently sat at just north of $50k. Gaurav reveals the company is planning to drop the price down to $200, despite it currently being priced higher on Kickstarter, and that would include bringing it down for anyone who's backed so far. This would make it more competitive with other fitness trackers when it ships, with July the current set release date.

The Fat Band and Breath are promising something great, but the jury will be out until we can actually try one ourselves and see how it compares against more rigorous medical testing.



