VFit

A weight-loss tracker that works out what you actually burn — from your own scale and food log — and tells you whether your metabolism is slowing down.

Your real TDEE — learned from your weight trend and intake, not a generic formula
Metabolic adaptation — how much your burn has dropped beyond what the weight you lost explains
Do next — how you've managed so far, and one concrete change: eat this much less, walk this much more, or hold steady
Forecasts & plateaus — where your weight will settle, 4/12/26-week projections, goal date, stall detection
Your day as a timeline — check-in, meals, snacks, exercise and 2-hour blood sugar, in order
Saved meals — search-as-you-type picker; log a usual meal in two taps
Fasting days — mark a fast and still log soups and juices
The year at a glance — every day coloured by what won: exercise, diet, fasting, or a day you lived a little — with targets, so you can see how much living is left
Trends you can scrub — status tiles and charts; slide a finger across any chart to read that day's values
Blood sugar & blood pressure — fasting and post-meal glucose, BP and pulse alongside weight
Bring your spreadsheet — CSV import, and export of everything any time
100% local — no account, no sync, no tracking

⬇ Download APK (Android) How it works

Do next: how you're doing, and what to change

Most trackers stop at charts. VFit's Do next tab tells you how to evaluate your health management so far — and what to do about it.

Year at a glance: counts of exercise, diet, fasted and lived days, days left against targets, and a calendar grid of the year — **The year at a glance.** Every day gets one colour for what won: a fasting day; a day you ate more than you burned (lived); or a deficit that came mostly from exercise or mostly from diet. Set a target share for each and it shows how many days of each are left — how much living you still have this year. The year can start on 1 January or on the day you began.

Next step card: eat about 700 kcal a day less, or move more, with the numbers behind it — **One next step, with numbers.** Compares what you've been eating with what your goal rate needs, using your measured expenditure. If you've stalled, it says why it thinks so — deficit closed, water masking fat loss, or not enough logging — and what to try: eat this much less, walk this much more, or hold steady and re-check.

How it works

Calorie calculators guess your expenditure from age, height and weight. VFit measures it instead: if you logged eating 2,000 kcal a day for a month and your weight trend held steady, you burn about 2,000 kcal a day — in your logging units, so consistent under-logging is absorbed rather than throwing the numbers off.

1. Log a little every day Morning weight, what you ate (saved meals make it quick), and optionally waist, exercise, blood sugar and BP. Missed a day? It's filled from the days around it and shown as assumed.

2. A filter separates signal from noise A Kalman filter tracks your true weight through day-to-day water swings and learns your expenditure as it goes. Each estimate uses only the data up to that day.

3. You get answers, not just graphs Your TDEE with a confidence range, adaptation since you started, where you'll settle at current intake, whether you've plateaued and the likely reason — and what to change.

Installing the APK

VFit is not on the Google Play Store. Install it directly — this needs installs from unknown sources enabled. Android 8.0 or newer.

Download the APK
Tap "Download APK" above, or get vfit.apk from the Releases page.
Allow installs from unknown sources
When prompted after opening the APK, tap Settings → enable "Allow from this source".
Open the APK and install
Open the downloaded file from your notifications or Downloads folder. Tap Install.
Set up and start logging
In Settings, enter your height, age and goal. Log tomorrow morning's weight and your meals. Estimates start after about three weeks; already have a spreadsheet? Use Import CSV.

About this app

VFit is local only. Your weight, meals and health readings stay on your device. No account required. No data leaves your phone. No analytics, no tracking, no ads.

It started as a spreadsheet and a Python script to answer one question during a weight-loss program: is my metabolism slowing down more than the weight I've lost explains? The app runs the same model on your phone.

The code was written by Claude Code. The intent, design, and product decisions were made by a human. The animation above uses made-up demo data.