Until recently, getting a blood glucose measurement required a finger stick. The whole process was so painful and annoying that only diabetics taking insulin bothered to do it regularly. But there’s a new class of devices called continuous glucose monitors, or CGMs, that make getting a glucose reading as easy as glancing at your smartwatch to see your heart rate. A CGM is a patch with a tiny electrode that goes into your skin to measure glucose levels in the interstitial fluid, plus a radio that sends the measurement to an external device like your phone. The devices are pain-free to use, and they’re rapidly coming down in price. Harry's guest today, Maz Brumand, is head of business at Levels, a startup that wants to use CGMs to help everyone understand how their choices about food and lifestyle affect their health.