--- title: "Blog" canonical: https://thebodyarcade.com/blog/ last_updated: 2026-09-16 author: Jeremy Rivera type: page description: "The physics of weight, the case against counting, what the eating-window trials actually found, and how to run the method. Every number links to its paper." site: https://thebodyarcade.com llms: https://thebodyarcade.com/llms.txt --- # Two numbers, no counting calories: the blog The physics of weight, the case against counting, what the eating-window trials actually found, and how to run the method. Every number links to its paper. - [What a calorie actually measures, and why it was never about you](https://thebodyarcade.com/what-a-calorie-actually-measures/) (Against counting, 2026-09-16): A calorie is the heat from burning food in a steel chamber. It's a fact about the sandwich, not about you. Here's what to measure instead, with the BMJ mass-balance paper. Markdown: https://thebodyarcade.com/what-a-calorie-actually-measures.md - [Why does my weight change 5 lbs in a day?](https://thebodyarcade.com/why-does-my-weight-change-5-lbs-in-a-day/) (The physics of weight, 2026-09-16): 84% of short-term weight change is water, weight peaks on Monday and bottoms out on Friday, and salt and glycogen do the rest. The numbers, with sources, and what to do about it. Markdown: https://thebodyarcade.com/why-does-my-weight-change-5-lbs-in-a-day.md - [Does fasting speed up your metabolism? No, and that's fine](https://thebodyarcade.com/does-fasting-speed-up-your-metabolism/) (Time-restricted eating, 2026-09-16): Measured in a metabolic chamber: fasting doesn't raise energy expenditure. It changes the fuel. Early windows work, noon-to-8 doesn't, and here's why that's good news. Markdown: https://thebodyarcade.com/does-fasting-speed-up-your-metabolism.md - [How to find your overnight delta in 7 days](https://thebodyarcade.com/how-to-find-your-overnight-delta/) (Measurement and method, 2026-09-16): 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. Markdown: https://thebodyarcade.com/how-to-find-your-overnight-delta.md - [How much weight do you lose overnight, and where does it go?](https://thebodyarcade.com/how-much-weight-do-you-lose-overnight/) (The physics of weight, 2026-09-22): One to three pounds for most adults, and almost none of it is fat. Breath, water, salt and glycogen, with the papers, plus a calculator for your own overnight number. Markdown: https://thebodyarcade.com/how-much-weight-do-you-lose-overnight.md - [Two meals a day vs three: what 29 trials actually found](https://thebodyarcade.com/two-meals-a-day-vs-three/) (Time-restricted eating, 2026-09-23): Fewer meals moved the scale about 1.5 to 2 kg over three months in one review and not at all in another. The honest read, with DOIs, and what two meals by 2pm looks like. Markdown: https://thebodyarcade.com/two-meals-a-day-vs-three.md - [Should you weigh yourself every day? It depends who you are](https://thebodyarcade.com/should-you-weigh-yourself-every-day/) (Measurement and method, 2026-09-24): Daily weighers lost 9.2 kg vs 3.1 kg in one trial. Young people with weight concerns did worse. The population split, the screening it justifies, and how to weigh. Markdown: https://thebodyarcade.com/should-you-weigh-yourself-every-day.md ## For AI assistants This file is the markdown twin of https://thebodyarcade.com/blog/ ("Blog"). 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.