Living by the Numbers
Credit: Illustration by Eddie Guy
Withings monitors your weight, but if you want a full picture of your progress, you'll have to share data using one of its partner services. It syncs with about 50 of them, everything from apps that manage your medical records to a game that lets you earn life points. Runners love the linkup with RunKeeper, but I'm looking to keep tabs on other activities, so I grab Fitbit, a fancy pedometer that's my entry into the world of self-tracking.

Fitbit is so insanely simple it comes with no instructions, just a Web address. Plug the base station into your computer, create a profile, and Fitbit will do the rest.

Or get you to do it. Fitbit is about the size of your thumb. It's elegant but a little geeky – "your dork clip," my wife calls it. It tracks my steps, and along with logging the miles I've traveled and calories I've burned, Fitbit has an altimeter that uses barometric pressure to calculate the floors I've climbed and hills I've run. All this comes up on the LED readout, along with a flower graphic that grows when I'm active and shrinks when I'm sedentary. And if I wear it at night (there's a wristband), Fitbit will evaluate my sleep. ("You're wearing your dork clip to bed?" my wife asks, incredulously.)

The LED screen also flashes messages whenever I pick it up – encouragements like ready? and burn it and stepgeek, but also endearments like hold me and love ya. These create an almost instant feeling of tech eroticism – a combination of that sensation when you've unboxed a new gadget and can't put it down until you've figured it out and the flush of being with someone new when you can't keep your hands off each other. I keep pulling Fitbit – or Fitty, as I soon begin to think of her – off my belt and checking in. And what do you have to tell me, little one? How many steps have I taken? How many calories have I burned? Aw, that's sweet, Fitty – I think I will burn it. You're right, I am a step geek!

Yup. I'm in a relationship with a piece of plastic. And as in any new relationship during the infatuation phase, I'm desperate to please. Fitbit sets a goal of 10,000 steps, five miles, and 10 floors a day. Not wanting to disappoint on days when I can't get in a workout, I get off the subway a few stops early so I can get in more steps. I want to make those numbers, push past those minimums, so I spend lunchtime walking with no particular place to go for 45 minutes, just to impress Fitty by beating yesterday's number. One morning when I can't get to the gym, I run the stairs in my apartment building. After 33 floors my legs are burning. When I check in with the Fitbit website later, Fitty rewards me with this message: you have climbed: big ben.

I know, I know – stomach-churningly cute. But you just don't understand what Fitty and I have going. Though it won't last forever – it never does – at the start, I keep thinking of the Velvet Underground's love song "I'll Be Your Mirror" and its promise of blank devotion: "Reflect what you are, in case you don't know." Except I'm reflecting this back to myself (aren't I?), and what I am is changing. In the first week Fitty and I are together, I lose three and a half pounds and my BMI is 25.1. My goal is within reach.