Weight
Trend line with per-day over/under-TDEE bands from the previous day. The hero chart. kg or lb.
Health Connect · Apple Health · Offline
Read your body like data.
decoderHealth pulls eleven metrics out of the health store you already have and lines them up against one number that matters: your weight. No cloud account needed to read them. No activity multiplier guessed from a dropdown. Every insight is arithmetic you can check.
11Metrics in one view✦
0Cloud uploads required to read✦
2Health platforms, one contract✦
48Studies behind the coaching✦
72hLongest fasting target✦
4Check-ins a day, spaced to your wake time✦
01 — The metric matrix
Eleven signals.
One target.
Nine come from Health Connect or Apple Health and stay theirs. Two, fasting and check-ins, have no native type anywhere, so decoderHealth keeps them locally. Manual entries you add are written back. Synced records are never rewritten.
Steps
Read through the platform aggregate so two watches never double-count a walk.
Activity
Exercise sessions enriched with distance, calories and steps that overlap them.
Calories
Daily meal stacks with a dashed TDEE overlay. Feeds energy balance directly.
Nutrients
Field-by-field mapping. Rolling intake against bundled DRI values for your age and sex.
Sleep
Sessions grouped into nights, stages when the source records them.
Water
ml or oz. Today's total is marked in progress so nobody calls it low at 10 a.m.
Glucose
Both unit systems handled at the boundary, never in the chart.
Cycle
Flow and period records surfaced alongside weight so the pattern is visible, not guessed.
Fasting
12:12 to OMAD and extended fasts past 72 hours, with cited phase markers on the ring.
Check-in
Mood and energy, four times a day, spaced across the hours you are actually awake.
Body fat
Read from BIA-capable scales through the health store. decoderHealth never estimates it.
02 — How it works
Arithmetic,
not vibes.
The dashboard does the math out loud
- BMI from weight and height. Nothing hidden.
- BMR by Mifflin-St Jeor from your profile and latest weight.
- TDEE prefers total burn, then BMR plus active calories. Never a static multiplier.
- Energy balance is intake minus TDEE, per day, banded green, orange, red.
Every chart has an entry button
- Tap the accent FAB on any metric to add a point.
- Manual rows are the only thing written back to Health Connect or Apple Health.
- Range presets, pull-to-refresh, and a raw-data dialog with ISO-8601 timestamps.
- Every quantity is comma-grouped through one formatter.
Fasting with the phases marked
- Time-restricted presets from 12:12 to OMAD, plus single extended fasts.
- Fed, post-absorptive and switch markers placed on the ring where the evidence puts them.
- Each phase links to a cited reference screen.
- Completed fasts and their edits live on a dedicated history screen.
Check-ins timed to your day
- Four reminders spaced across your average awake window, not the clock.
- Mood and energy captured in two taps.
- A heatmap shows the week without a single sentence of interpretation.
An AI that has read your numbers
- Ask about weight, TDEE, water, sodium or a monthly BMI trend in plain language.
- Answers come from the same data the dashboard shows, in your preferred units.
- Partial days are labeled in progress so it never calls a half-logged day low.
- The Buddy surfaces one cited finding at a time, never a lecture.
03 — Why it is different
Rules we
don't break.
-
Offline first
Every metric reads and charts without an account. The health store is the source of truth. The local database is a disposable read-model.
-
No guessed multipliers
Activity level is derived from recorded burn, never from a "moderately active" dropdown you picked once in 2023.
-
Write back only what you typed
Your watch's records stay exactly as your watch wrote them. Only manual entries go outbound, through one service.
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Cited or silent
Coaching rules trace to 48 verified studies. If there is no evidence, the Buddy says nothing.
-
Diagnostics without payloads
Sync failures are captured, redacted and bounded. No measurements, record IDs or stack traces are ever persisted.
"First app that told me my TDEE came from total burn instead of a multiplier. I finally believe the number."
"The weight chart with the over/under bands from the day before is the only visualization I have ever changed behavior over."
"I asked it for sodium and water together and it flagged that today was still in progress. Small thing. Nobody else does it."
"Fasting ring with the phase markers cited. I stopped reading fasting blogs."
04 — Pricing
Reading is free.
Talking is Pro.
Every metric, chart, manual entry, fast and check-in works without paying. Pro unlocks the chat and the Buddy's coaching. Access is one entitlement, managed through the store.
Free
$0
- All eleven metrics and charts
- Manual entry with write-back
- Fasting timer and history
- Check-ins and reminders
- BMI, BMR, TDEE, energy balance
Pro · Monthly
$9.99/ MO
- Everything in Free
- Chat with an AI that reads your data
- Buddy coaching with cited evidence
- Unit-aware answers, in-progress labels
- Cancel from the store any time
Pro · Annual
$59.99/ YR
- Everything in Pro Monthly
- Save 50% vs monthly
- One entitlement across Android and iOS
- Restore purchases on any device
05 — Questions
Fine print,
large type.
Where does my data live?
In Health Connect on Android or Apple Health on iOS. decoderHealth keeps a local read-model to draw charts fast and can throw it away at any time. Fasting and check-ins have no native type, so they stay in the on-device database.
Does it change my existing records?
No. Only entries you type into decoderHealth are written back to the health store. Records synced from a watch, scale or other app are never rewritten.
How is TDEE calculated?
Total calories burned when the source records them, never below your BMR. Otherwise BMR plus active calories, then BMR plus exercise-session calories. There is no self-declared activity level anywhere in the app.
What does the AI see?
Aggregated series for the metric and window you ask about, in your display units, with derived BMI, BMR, TDEE and energy balance. Partial periods are marked in progress. Your profile's identifying fields are not sent.
Android or iOS?
Android first, through Health Connect. The iOS build reads Apple Health through the same metric contract. A single Pro entitlement covers both.
06 — Early access