You want to lose weight, but not by guessing a number off a wrapper. You want a number that’s actually yours. Here’s how to get one in 7 days with a bathroom scale and a sheet of paper.
What you’re measuring
Two readings a day. The first is your Morning weight: step on the scale when you wake up, before breakfast or a glass of water. The second is your Night weight: step on again right after your last meal of the day, which on this method ends at 2pm (or 8 hours after you wake, if you’re not on a 6am schedule). Same scale, same floor, same clothes or none. If you’ve read the book, these are your MIN and your MAX.
Night minus the next Morning is your delta: the mass that left your body between your last meal and the next morning. Most of it is water and breath, not fat, and I won’t pretend otherwise. What matters is that it’s consistent enough, once you’ve seen it seven times, to plan against.
Why does Night matter more than Morning? Because Morning is where everyone looks, and it’s mostly a record of how dehydrated you woke up. Night is your ceiling: the number you actually control, because it’s set by what you ate and drank. Once you know your delta, tonight’s ceiling is the only lever you touch.
Why daily, and why seven days
Daily weighing works. In a six-month trial, adults who weighed every day lost 9.2 kg; the ones who weighed less often lost 3.1 kg, and the less-often group was still weighing 5.4 days a week.
Seven days, because your weight has a weekly rhythm. In 80 adults logging 4,657 weigh-ins, the weekly high landed on Sunday or Monday 59% of the time and the low on Friday or Saturday 60% of the time (Orsama et al., Obes Facts 2014). A full week holds every day once, so the weekend high and the Friday low both land in your baseline and neither one gets counted twice. Take the median instead of the average and one salty Sunday can’t drag your number around either.
The first week, step by step
- Print the sheet or open the spreadsheet. Here’s the PDF for the fridge and here’s the XLSX that does the arithmetic. Free, no signup.
- Every day, two numbers. Morning on waking. Night after your last meal. Write the time of your last meal next to it, because you’ll want to know later which nights the water came from a 9pm snack.
- Don’t change anything else yet. No targets, no adjustments, no goals. The first week is calibration. If you also start dieting, you’ll never know what your delta actually was.
- Flag the weird days. Different scale, travel, sick, a salty blowout: tick the flag and leave that row out of your baseline. There is no failed day. You’re taking readings, not passing a test.
- Day 8: take the median of the drops you didn’t flag. Seven nights, seven drops, and the middle one is your number. The sheet puts the average next to it, so you can see when one weird night is pulling. Mine came out steady enough that I stopped checking whether it was “real” and started using it.
What to do with your number
From day 8 you manage one thing: tonight’s Night weight. Take this morning’s weight, add your median overnight drop, subtract a small daily step for the rate you want, and that’s tonight’s ceiling.
tonight’s ceiling = this morning + your median overnight drop − (weekly rate ÷ 7)
Default rate: half a pound a week, a daily step of about 0.07 lb. You can go faster, but not past 2 lb a week, because that’s the top of the range the CDC calls gradual and steady, and I built the app to refuse anything above it. You eat and drink until you approach the ceiling, then you stop. You keep logging your Morning weight so the delta stays honest. That’s the whole discipline.
Three things that will trip you up
- The delta drifts. As you lose mass, your overnight rate changes. Recalibrate for a week every four to six weeks, or sooner if the numbers stop matching.
- A great morning is not a trend. An unusually low reading tends to be followed by a less unusual one for statistical reasons alone. Plan from the median, never from your best day.
- Hunger is real. In the trials of eating twice a day, the hunger hormone ghrelin went up, not down. A 2pm cutoff puts the hungry hours at night, where you can sleep through them instead of snacking through them. That’s a feature, but it’s also a warning: if food is already a source of anxiety for you, read this first.
That’s the manual version, and it’s how I ran it for a year. The app does the same arithmetic without the paper, smooths the noise into a line, and sets tonight’s ceiling for you. It’s open now: free for life to the first 100, then $1 a month. Or keep using the sheet; it does the same job. Two numbers a day. What’s your delta going to be?