Breathalyser can tell if you are burning fat from a single exhalation - Nature

What the report says

Nature.com reports that researchers have developed a compact breath-testing device intended to show, from a single exhalation, whether a person’s body is in ketosis — a metabolic condition associated with using fat-derived molecules for fuel. The handheld system is designed for home use and could offer people trying to manage weight loss quicker feedback than waiting for changes in body weight, though the researchers say broader testing is still needed.

According to Nature, the device measures acetone, a volatile ketone-related compound released in breath when fatty acids are broken down during fasting, exercise or dietary changes. The developers say the system differs from many consumer breath tests because a smartphone app guides how the user exhales, and the device separates acetone from breath before measurement, reducing interference from humidity and the surrounding environment. The work was reported in the journal Device.

The research team evaluated the breathalyser in a small study involving 12 healthy volunteers who underwent exercise and dietary interventions meant to shift metabolism. Results from the handheld detector were compared with proton transfer reaction time-of-flight mass spectrometry, a laboratory breath-analysis method described by Nature as a gold standard. The authors reported strong agreement between the two approaches.

Nature notes that Andreas Güntner of ETH Zurich helped develop the device and that two authors, including Güntner, are shareholders in Alivion, an ETH Zurich spin-off that has commercialized the technology under the name Nutrion. ETH Zurich holds the patent. The finding matters because existing ways to track fat metabolism can be invasive, clinic-based or insufficiently validated, but the evidence so far comes from a limited trial.