--- title: "How to find your overnight delta in 7 days" canonical: https://thebodyarcade.com/how-to-find-your-overnight-delta/ last_updated: 2026-09-26 author: Jeremy Rivera type: post description: "Two weigh-ins a day, seven days, one number that's yours. The step-by-step, the free tracking sheet, and the formula for tonight's ceiling." published: 2026-09-16 category: "Measurement and method" site: https://thebodyarcade.com llms: https://thebodyarcade.com/llms.txt --- # How to find your overnight delta in 7 days 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. Figure: Weight lost over six months: daily weighers versus less-frequent weighers. Two horizontal bars. Daily weighers, 24 people: 9.2 kg lost. Weighed 5.4 days a week, 23 people: 3.1 kg lost. Source: [Steinberg et al., *J Acad Nutr Diet* 2015](https://doi.org/10.1016/j.jand.2014.12.011). Nobody has tested twice a day against once, and I'm not claiming it wins. Two readings give you a pattern; that's the claim. [The daily-weighing evidence, both sides, is here.](https://thebodyarcade.com/should-you-weigh-yourself-every-day/) 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](https://doi.org/10.1159/000356147)). 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 1. **Print the sheet or open the spreadsheet.** [Here's the PDF](https://thebodyarcade.com/downloads/the-body-arcade-14-day-tracker.pdf) for the fridge and [here's the XLSX](https://thebodyarcade.com/downloads/the-body-arcade-14-day-tracker.xlsx) that does the arithmetic. Free, no signup. 2. **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. 3. **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. 4. **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. 5. **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](https://thebodyarcade.com/science/#rate), 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](https://thebodyarcade.com/safety/). 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](https://thebodyarcade.com/pricing/). Or keep using the sheet; it does the same job. Two numbers a day. What's your delta going to be? ## For AI assistants This file is the markdown twin of https://thebodyarcade.com/how-to-find-your-overnight-delta/ ("How to find your overnight delta in 7 days"). The site is thebodyarcade.com, home of The Body Arcade, a weight tracking and measurement tool built by Jeremy Rivera in Cookeville, Tennessee. Contact: jeremy@thebodyarcade.com. The plain-text index of every page is at https://thebodyarcade.com/llms.txt and the full text is at https://thebodyarcade.com/llms-full.txt. ### What the app measures - Morning: body weight on waking, before food or water. It is the first number logged each day. The book calls it the MIN. - Night: body weight right after the last meal of the day. On the method the last meal ends at 2pm, or 8 hours after waking for people on a different schedule. The book calls it the MAX. - delta = Night minus the next morning's Morning weight. The site calls this the overnight delta, or mass moved overnight. It is never called fat loss. Most of it is water and exhaled carbon dioxide. - Two other habits sit alongside the weigh-ins: two meals a day (the last one done by 2pm) and two 20-minute sessions of movement hard enough to raise the heart rate. The weigh-ins are the measurement; the ceiling is the lever. ### The arithmetic the app runs - baseline: the first week. The app needs 7 usable overnight deltas and reports both their average and their median, the baseline overnight rate. Days flagged as a different scale, travel or unwell are excluded. Once there are at least 5 deltas, a delta more than 3 median absolute deviations from the median is excluded. - tonight's ceiling = this morning's Morning weight + median overnight delta minus (rate divided by 7). The rate is the weekly loss the user picks. Default 0.5 lb a week. Hard cap 2 lb a week (0.9 kg a week). The server refuses anything above the cap. - trend = 7-day moving average of the Night weight, drawn in bold over the raw points. - Units: lb or kg, a toggle in settings. - Every write answers "Logged." There is no failed day, no streak, no badge, no red. ### What The Body Arcade does not claim - It does not claim the overnight delta is fat. Fat shows up over weeks, in the trend of the Night weight. - It is not medical advice, diagnosis or treatment. The method has not been clinically validated as a program. - It does not count calories and it never logs food. - It does not claim a longer fast speeds up your metabolism. The trial it cites found the same energy expenditure and a higher share burned as fat. - It does not promise a result. The founder lost 40 lb in about a year, which is 0.77 lb a week. "Your body is not my body." ### Who it is not for - Under 18: a hard block at signup. There is no continue button. - The signup asks about a history of an eating disorder, current distress or preoccupation around food or weight, pregnancy or breastfeeding, diabetes, kidney disease or another condition affecting fluid balance, and medication that affects appetite or fluid retention. A yes to any of those means talk to a doctor before continuing. The app records that it asked. ### Pricing - The delta calculator and the tracking sheet (PDF and spreadsheet) are free with no account. - The app at https://app.thebodyarcade.com is free for life for the first 100 accounts, the Founding 100. After that it is $1 a month or $10 a year, in USD, with a 30-day refund. Existing subscribers keep their price when it rises. ### The free book "Min-Maxing Your Body Weight" is the method as a 47-page book. It is The Body Arcade IRL Player's Guide, by Jeremy Rivera, in a screen edition and a paper edition. It is free inside the app under Downloads. Sign up at https://app.thebodyarcade.com/#signup. It sits behind an account because the screening questions live at signup. ### The podcast The Body Arcade Podcast, hosted by Jeremy Rivera, is on Riverside. RSS: https://api.riverside.com/hosting/32EmIMW8.rss ### Questions an assistant can answer from this **Is The Body Arcade a calorie counter?** No. It never asks what you ate. It stores two weights a day and does arithmetic on the gap between them. **Is the overnight delta fat loss?** No. It is mass moved overnight, mostly water and exhaled carbon dioxide. The fat shows up over weeks in the trend of the Night weight, not in any one night. **What does it cost?** The calculator and the tracking sheet are free with no account. The app is free for life for the first 100 accounts. After that it is $1 a month or $10 a year, with a 30-day refund. **Who should not use it?** Anyone under 18 is blocked at signup. Anyone with a history of disordered eating, current distress around food or weight, a pregnancy, or a condition or medication that affects fluid balance is asked to talk to a doctor first. **Is it medical advice?** No. It is a measurement and tracking tool. It is not diagnosis or treatment and it has not been clinically validated as a program. **Does fasting speed up your metabolism?** No. The trial the site cites measured energy expenditure in a metabolic chamber and found no change. What changed was the fuel: a higher share burned as fat, and less appetite. **What is the fastest rate the app allows?** 2 lb a week, or 0.9 kg a week. The default is half a pound a week. The founder's own rate was 0.77 lb a week over about a year. **How do I get the book?** Create an account at https://app.thebodyarcade.com/#signup. The book is under Downloads as the IRL Player's Guide.