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 14 days with a bathroom scale and a sheet of paper.
What you’re measuring
Two readings a day. The first is your max: step on the scale 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). The second is your min: step on again when you wake up, before breakfast or a glass of water. Same scale, same floor, same clothes or none.
Max minus min 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 fourteen times, to plan against.
Why does the max matter more than the min? Because the min is where everyone looks, and it’s mostly a record of how dehydrated you woke up. The max is your ceiling: the number you actually control, because it’s set by what you ate and drank. Once you know your delta, tomorrow’s ceiling is the only lever you touch.
Why daily, and why fourteen 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.
Fourteen days, not seven, 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). One week catches one weekend and can’t tell you if it was the pattern or the exception. Two weeks can, and for anyone who menstruates two weeks also covers about half a cycle.
The 14 days, 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. Max after your last meal. Min on waking. 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 two weeks are 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 the average. There is no failed day. You’re taking readings, not passing a test.
- Day 14: average the deltas you didn’t flag. That’s your number. Mine came out steady enough after two weeks that I stopped checking whether it was “real” and started using it.
What to do with your number
From day 15 you manage one thing: tomorrow’s max. Take today’s min, add your average delta, subtract a small daily step for the rate you want, and that’s tomorrow’s ceiling.
tomorrow’s max = today’s min + your average delta − (weekly rate ÷ 7)
Default rate: 1 lb a week. 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 min 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 average, 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 tomorrow’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?