> To me, my glucose number is completely impersonal. I wouldn’t care who knew this or not, it has little to do with my personhood

I'm not sure how much information a continuous glucose would reveal about you since I've never tried one. How healthy your diet is probably. Does it spike in the morning? Could it indicate when you sleep and when you wake? What other things can affect it? Sickness? Stress? Drugs/alcohol? A single reading may not tell anyone much, but I imagine that over time the patterns and sudden changes to them could reveal a lot about your life.

That kind of data might be used against you in a lot of different ways. Maybe it's higher or lower than normal often enough that it triggers some threshold and your health/life insurance company raises your rates. Maybe you get in an accident one day and the person who hit your car subpoenas those records and uses it to show that you're blood sugar was a bit low allowing them to suggest that you must have been drowsy or impaired and so the accident was your fault. Maybe companies will notice that there are certain times of the day when it changes and you're more likely to be hungry or thirsty or tired or anxious. Times when you're more vulnerable to manipulation or suggestion.

Is it paranoia when they're really out to get you? The buying and selling of the most mundane aspects of our lives is a multi-billion dollar a year industry. Almost every company you interact with today involves themselves in it in one way or another and the reason every single company is so desperate to get their hands on every scrap of data they can is because it's extremely profitable. The data they collect is already making them money hand over fist, mostly at the expense of the people whose data was taken. That data lives forever. It never goes away, and all kinds of people are looking into new ways to take advantage of us using it. Corporations, politicians, extremists, scammers, employers, lawyers, advertisers, anyone willing to pay and looking for an advantage over you.

I suppose that taking even small steps to protect myself (to the extent that it's even possible) does mean that I miss out on trying some things in life. Not allowing myself to be taken advantage of by handing over vast amounts of data isn't always fun, but until we have protections under the law that make those small concessions unnecessary is it better to just try to pretend it isn't happening and hope I don't get screwed over too badly when the data I gave up inevitably comes back to bite me in the ass later?

Usually it just means a have to work harder to find more reasonable alternatives. I still turn my lights on and off and set kitchen timers, but I don't do it with smart assistants. I have to find (and sometimes build) offline options for things like security cameras or backup solutions, and I have to search harder for things like pedometers and color changing light bulbs that aren't controlled by cell phone apps. I have to search for dumb TVs and cars.

I know that kind of effort it isn't worth it for everyone. Most people never notice when the data they give up is used against them. They don't know that the price they paid is higher than the price their neighbor paid for the extract same item. They don't know they waited longer on hold because they were pushed back so someone else who called in after them could be pushed ahead to the front of the queue. They aren't ever told why they didn't get that job or apartment they wanted. They'll never know about the products, services, or opportunities that they've been algorithmically excluded from. Most of the time it's all out of sight, out of mind. I just hope that people start paying better attention to what's happening because, like you, a lot of people feel like there's very little chance that they'll be robbed, but they're actually being robbed all the time, and it's going to get a lot worse.