What the number costs you

The scale costs nothing, sits in a corner, takes a minute. If it weren't for the swing, that would be the end of the accounting. But you've read chapter 12, so let's do the accounting properly, and let's leave weight out of it, because whatever the scale is costing you, weight isn't the currency.

It costs you the first minute of the day, which sounds trivial until you notice that the first minute sets the tone of the next hour, and that on perhaps half your mornings, if your sheet looks like the sheets I'd expect, you've handed that minute to a number made of water.

It costs you meals. The settling up in chapter 9 means that what you eat on any given day is partly decided by last night's salt. A skipped breakfast here, an unearned cake there, a hungrier four o'clock than there needed to be, and a pattern of eating that answers to the scale rather than to appetite. Over a year, that's several hundred meals bent slightly out of shape for no reason.

It costs you the mood you bring to other people. The short answer in the bathroom doorway. The temper on the school run. The evening spent being someone who had a bad morning, with a partner or child who didn't and can't see why.

It costs you clothes you own and don't wear, on the mornings the number says you can't. It costs you the mirror. It costs you a stance towards your body that's renewed daily and that Pacanowski's ten years suggest doesn't stay in the bathroom.

And there's a bigger one, which I'll only touch because it's a book of its own. When the number decides whether it's a good day, it's very easy for the number to start deciding when life starts. The holiday when the number's right. The photograph when the number's right. The swimming, the dress, the date. That's putting things off until a reading of water and glycogen says yes, and the reading never quite does, and years go.

What you get for all this, from chapter 2, is certainty, a warning, a score, honesty and control, and chapters 3 to 11 have argued that on a daily basis you get none of those, only the feeling of them, on the good mornings, at the price of the bad ones. Whether that's a good bargain is your call. I'd only ask you to see the whole bill before you decide.