One day in September, I stood in front of my open refrigerator, ravenous but unable to figure out what I should eat. I was worried that whatever I chose to eat would cause the new app on my phone to record a spike in my glucose levels that would count against the number I was allowed that day – and I was determined to conquer this algorithm. I’d just put on a continuous glucose monitor, a device that sticks to your arm and uses a tiny needle to provide near-real-time information about how much sugar is circulating in your blood – not because I have diabetes, the main use for what are called CGMs, but because these devices are starting to be marketed as wellness tools for everybody, and I wanted to see how they work.

Apple? Too sugary. Granola bar? Hello, glucose spike. Cheese – that’s the ticket.

A few days of wearing this monitor had taught me that cheese would not cause my glucose to go up. “Is this thing just inadvertently putting you on the keto diet ?” my husband – who’d witnessed a few episodes of hanger while I was trying to figure out how to please my CGM – finally asked. Pretty much.

Avoiding carbohydrates and prioritizing protein and fat, often together, didn’t lead to spikes in glucose that my CGM and app, Lingo from the health company Abbott, would count against me. But because I wasn’t aiming to switch to a very low-carb, ketogenic diet, I initially struggled to figure out what to eat; in the first week or so of wearing the CGM, my scale r.