How much did you lose overnight?

What the number actually means

It’s the mass that left your body between your last meal and this morning. Most of it is water, as vapour on every breath and through your skin, plus the carbon dioxide you exhaled while your body ran on its own reserves. It isn’t fat loss, and you won’t catch me calling it that.

One night tells you very little. Your weight swings a few pounds in a normal day from salt, fluid, and timing. But your delta, averaged over 14 nights, settles into a number that’s actually yours. Once you have it you can plan against it: set tomorrow’s ceiling a little lower than today’s, and the physics does the rest.

Track it for 14 days, on paper or in a spreadsheet

Here’s the free version of what the app does. Print the sheet and stick it on the fridge, or use the spreadsheet and let it do the delta and the average for you. Fourteen rows, two numbers a day, no signup.

The spreadsheet computes your delta and your 14-day average, and after day 14 it gives you tomorrow’s target max from the rate you choose. Doing it by hand for two weeks is also exactly how you’ll know whether you want the app.

How to weigh so the number’s worth keeping

1. Same scale, same floor, same clothes (or none). A different scale is a different instrument. Flag it or skip it.
2. Max: right after your last meal of the day.
3. Min: on waking, before breakfast or a glass of water.
4. Write both down. The sheet above, a notes app, the back of an envelope. The app does it for you when it’s ready.

This isn’t for everyone. Here’s who it isn’t for.