People without diabetes are using glucose monitors to make healthier diet choices, but critics aren’t sold on this trend, reports the Wall Street Journal

What’s the better breakfast—oatmeal or eggs? Should you add a banana?

The answers vary because people vary. But for a more reliable solution, some people are turning to a continuous glucose monitor.

As unlikely as it seems, growing numbers are adopting a tiny flexible sensor you can affix with a tiny needle to the back of your arm. The sensor syncs with an app that tells you in real time which foods spike your blood sugar. The device, also known as a CGM, is used to treat diabetics, and outside of that, the market remains tiny—probably in the tens of thousands of users, according to two analysts.

But CGMs are getting traction in sports and tech especially.

Read more in the Wall Street Journal