New Delhi, Oct. 17 -- A 34-year-old walked into my clinic last month with 14 days of glucose graphs on his phone. He had colour-coded them. He wanted to know why a bowl of poha had pushed his glucose reading to 141 mg/dL and whether he should stop eating it forever. I asked him a few other things-whether he had measured his waist, whether he checked his fasting insulin, and did he know if his triglyceride levels were okay. He had no awareness of any of it. He had spent two weeks and a good deal of money watching one number move, without ever considering other factors.

This is what happens when one is obsessed with continuous glucose monitoring (CGM). To be fair to the technology, these monitors are useful, and for people on insulin they ...