Subten — User Manual

Version 1.0 · July 2026

Subten is intended for people aged 18 and over.

1 Foreword

Welcome to the user manual for Subten — the body-recomposition coach for iPhone and Apple Watch. Subten combines food logging (AI photo scanning, barcode, search), an adaptive calorie and macro engine that learns from your real results, a training module, deep Apple Health integration, and an AI mentor.

1.1 What you will find in this manual

This manual covers the whole app: from creating an account and the onboarding interview, through every tab and feature, to subscriptions, privacy and troubleshooting. It is a how-to-use guide: for every feature you will find what it is for, how to operate it step by step, and what the app shows you and why.

No prior nutrition knowledge is assumed. Wherever the app relies on a concept (calorie deficit, macros, energy availability, adaptive targets), the manual briefly explains it in plain language.

You can read the manual two ways:

• From the beginning — Parts I and II introduce the concepts and get you set up; then continue with the screens you use most.
• As a reference — each chapter is self-contained. Chapters describing screens share the same structure, so the same type of information is always in the same place.

1.2 How the manual is organized

Screen chapters (Part III) share a fixed structure: What it is for → Quick start → Step by step → Fields and options → Connections to other screens → Common mistakes → Limitations.

1.3 Typographic conventions

• Bold marks a user-interface element — a button, menu item or tab name: tap Save.
• Italics mark a value or state the app displays: the ring turns red when you are over target.
• Monospace marks something you type.
• Boxes labelled Tip, Note and Warning highlight shortcuts, context and pitfalls.

Note: Subten’s interface is available in English, Slovak and Czech. This manual uses the English interface; the Slovak and Czech editions of the manual use the corresponding localized labels.

2 Part I — Introducing Subten

2.1 What is Subten

Subten is an iOS app (with an Apple Watch companion) for body recomposition — losing fat, building muscle, or both. Its tagline is blunt: “−10 kg. No excuses.” Underneath the bluntness sits a careful engine:

• You log what you eat — by photo (AI), barcode, search, label scan or manually.
• You log (or import) your training and your weight.
• Subten reads activity, sleep and recovery data from Apple Health.
• Every week, the adaptive engine compares what you actually ate with how your weight actually moved, measures your true maintenance, and adjusts your daily calorie and macro targets — with safety rails.
• The AI mentor (Coach tab) reviews your day and week, explains what the numbers mean, and can log food or activities for you.

Subten is designed for adults: the app enforces an 18+ age gate during onboarding.

2.2 Key concepts

The energy model: Remaining = Goal − Eaten

Subten uses a single, deliberately simple energy formula on every screen:

Remaining = Daily Goal − Eaten

Your Daily Goal already accounts for your planned activity. Unlike many calorie apps, exercise does not inflate your remaining budget: a workout does not “earn” you extra food by default. Activity from Apple Health is shown for information. Only when your measured movement clearly exceeds your plan does the app extend the day’s target, shown as Goal + Extra movement. This prevents the classic double-counting trap where optimistic exercise estimates cancel out your deficit.

Adaptive targets and calibration

Your initial targets come from a standard estimate (the Mifflin–St Jeor equation plus an activity multiplier). Estimates are wrong for almost everyone — so Subten treats them only as a starting point. For roughly the first two weeks the app is calibrating: it needs enough logged days and weigh-ins before it trusts the data. After that, targets are re-derived weekly from your real intake and real weight trend. Part IV explains the rules and safety rails in detail.

Plan vs Reality

Your training plan drives your nutrition targets (training days can carry different targets than rest days — see day types below). What Apple Health measures is used to check reality against the plan, not to rewrite it minute by minute.

Day types

Each day has a type — Strength, Cardio, Rest or Custom — shown as a badge on the Food tab. Day types allow carb cycling: the daily target can differ by day type. Special day types set by strategies (cheat day, refeed, diet break) are excluded from the weekly adaptation so one planned high day doesn’t distort your statistics.

Free vs Premium

The core loop is free: food logging by search, barcode and manual entry, the dashboard, the My Plan training tab, progress tracking, Apple Health sync, reminders, and data export/import. Premium unlocks the AI features (photo scanning, label scanning, meal plans, the Coach) and the full training module (Gym, Sport, Personal Records). Chapter 9 has the full comparison.

2.3 A map of the app

The app has five tabs:

Settings are reached from the gear icon on the Today tab.

3 Part II — Getting started

This part takes you from installing the app to your first fully set-up day.

3.1 Quick start

1. Open Subten. On the welcome screen tap Get Started (or I have an account if you already registered).
2. Complete the 6-step onboarding: profile → activity level → goal → optional training plan → Apple Health.
3. Tap Done. Your free trial starts and you land on the Today tab.
4. Log your first meal: Food tab → + at a meal → search, scan a barcode, or take a photo (Premium).
5. Add today’s weight on the Progress tab so calibration can begin.
6. Optional: in Settings → Reminders switch on meal, water and weigh-in reminders.

3.2 Creating an account and signing in

On first launch Subten shows the sign-in screen. You can create an account three ways:

You must agree to the Terms before the Apple/Google buttons become active.

Forgot your password? Tap Forgot password?, enter your e-mail, and follow the link in the reset message — it opens the app directly on the new-password screen.

3.3 Onboarding step by step

Onboarding is a 6-step interview with a progress indicator (Step X / 6). You can go Back at any time; step 5 can be skipped.

Warning: Subten is for adults only. The date-of-birth picker will not accept a date that makes you younger than 18.

Step 1 — Welcome. The app introduces itself. iPhone 15 Pro and newer also show a tip: you can map the Action Button to quick-add food.

Step 2 — Profile. Choose Gender, set your date of birth, height (120–220 cm), current weight and target weight (35–200 kg each). These feed the initial calorie estimate.

Step 3 — Activity level. Pick from Sedentary, Light, Moderate, Active, Very active — each card explains what it means in workouts per week. Choose honestly; the adaptive engine will correct estimation errors, but a realistic start converges faster.

Step 4 — Goal. Choose Burn fat, Build muscle, Recomposition or Maintain.

• Fat loss adds a Pace picker (Slow / Medium / Fast).
• Muscle gain adds a Training experience picker (Novice / Intermediate / Advanced) — experienced lifters gain muscle more slowly, so the surplus is smaller.

A live preview card shows your starting targets: daily kcal, protein/carbs/fat, the deficit or surplus, your estimated time to goal, and your BMR and TDEE.

Step 5 — Training plan (optional). Pick a training split: Full Body 3×, Upper/Lower 4×, Bro Split 5× or Push/Pull/Legs 6×. You can change or build a custom plan later on the Training tab.

Step 6 — Apple Health. Subten explains what it wants to read (weight, steps, heart data, sleep…). Tap Allow access and confirm in the iOS sheet. You can also skip this and enable it later in Settings → Health. Tap Done — your profile is saved and your free trial starts.

3.4 First settings worth checking

• Language — Settings → Language: English, Slovak or Czech (requires an app restart).
• Units — Settings → Units: kilograms or pounds (display only; data is stored in kg).
• Reminders — Settings → Reminders: breakfast, lunch, dinner, water, training (workout days only) and weigh-in, each with its own time.

4 Today (Dashboard)

4.1 What it is for

The Today tab is your home screen: one glance tells you how the day is going — energy budget, activity, water, recovery, planned training and logged meals. It is also the launch pad for the most frequent actions.

4.2 What you will see

From top to bottom (cards appear only when relevant):

• Banners — health alerts (from Apple Health anomalies), an active life situation, and during the first ~2 weeks the Calibrating your targets banner: “Keep logging meals and weigh-ins for ~2 weeks — we’ll fine-tune your calories from your real results.”
• Greeting with your goal and your streak (consecutive days of logging, shown as a flame).
• Energy ring — Eaten / Goal, with Remaining in the middle, an Energy Availability chip (low / watch / ok / optimal), and activity shown for information. When the weekly adaptation has just changed your targets, an Adapted this week badge appears here.
• Quick actions — Add food (opens a menu of logging methods), +250 ml water, Start training.
• Stats row — steps, exercise kcal, water.
• Sleep & Strain tiles and the expandable Recovery bar — a 0–100 recovery score built from HRV, resting heart rate, sleep, SpO₂, respiratory rate and wrist temperature, each with a plain-language explanation and a training recommendation.
• Performance Profile — a radar of recovery, strength and nutrition.
• Today’s training, a weight mini-card (7-day change) and today’s meals.

Note — no Apple Watch required. Subten reads the recovery score and every health metric (HRV, heart rate, sleep, SpO₂…) from Apple Health, not directly from a watch. The source can be anything that writes those metrics into Apple Health — an Apple Watch, Garmin, Oura, Whoop, other bands or rings, or even the iPhone itself (steps, sleep). If Apple Health holds no such data, recovery simply won’t appear.

4.3 Toolbar

• Gear — opens Settings (chapter 10).
• Heart circle — Life situations: temporary modes (illness, vacation, high stress…) that pause or soften the engine so a bad week doesn’t wreck your targets.
• History — browse past days in the same card layout.
• Lifestyle — water dosing and supplement tracking.

4.4 Common mistakes

• Expecting exercise to add food budget. By design it doesn’t (see the energy model, §2.2). Only clearly-above-plan movement extends the day’s target.
• Dismissing the calibration banner and judging targets on day 3. The first estimate is deliberately conservative; let the two-week calibration finish.

5 Food

5.1 What it is for

The Food tab is your diary: everything you eat and drink, organized by meal (Breakfast, Lunch, Dinner, Snack), with daily totals against your targets — including fiber.

5.2 The screen

• Date header — arrows for previous/next day, tap the date for a calendar.
• Daily totals card — calorie ring with Remaining, plus bars for protein, carbs, fat and fiber. The current day type badge (Strength / Cardio / Rest / Custom) is shown here.
• Meal sections — each with an add menu, a totals line, and one-tap chips of Recent and Frequent foods.
• Toolbar — Recipes, Copy from day (any of the last 7 days), Meal plan, Scan.

5.3 Ways to log food

Tip: Photo scans work offline too — they are queued and processed when you’re back online. A banner shows pending and failed scans; tap it to open the scan queue.

Tip for the best result: The scanner has three modes — Barcode · Label · Food. If a product isn’t found by barcode (missing from the Open Food Facts database), switch to Label mode and photograph the packaging’s nutrition table (values per 100 g or per serving). The AI reads the macros from it and fills them in for you — more reliable than estimating from a plate in Food mode.

5.4 Editing entries

Tap any food row to edit: change grams with a ±10 g stepper or presets (50/100/150/200/300 g), or override macros entirely. Swipe or use the context menu to favorite, move to another meal, copy to today (from a past day) or delete (with confirmation).

5.5 AI meal plan and shopping list (Premium)

Toolbar → Meal plan generates a full day of meals matching your current targets. You can state preferences in plain language (“Asian cuisine, no dairy”). Review the plan, tap add to day to log it, and open the Shopping list for the ingredients.

5.6 Common mistakes

• Trusting a photo scan blindly. The AI estimate is a starting point — check the portion size before confirming, especially for mixed dishes.
• Logging into the wrong day. Check the date header after using the calendar; the app keeps whatever day you navigated to.

5.7 Limitations

• Photo and label scanning require Premium and (for processing) an internet connection.
• Barcode coverage depends on the Open Food Facts database; regional products may be missing — use Quick add and save as a favorite.

6 Training

6.1 What it is for

The Training tab holds your plan, your workouts and your history. It has four sub-tabs: My Plan, Gym, Sport and Library.

6.2 My Plan (free)

Your active plan: a resume-workout banner if one is in progress, the week strip, today’s workout, a section of Apple Watch workouts you can import, weekly stats and your workout history. From here you can Add activity (log cardio manually) or Create training plan.

6.3 Active workout

Starting a workout opens the live screen: exercises with sets and reps, a rest timer, and a Live Activity on your lock screen so you can track rest without unlocking. Finishing a session records it to history and (if allowed) to Apple Health; new Personal Records are detected automatically.

6.4 Gym and Sport (Premium)

• Gym — the full catalogue of workout plans and templates.
• Sport — sport-specific plans (hockey, football, tennis, basketball…) delivered as Sport Packs.

Without Premium these sub-tabs show a paywall card.

6.5 Library

The exercise library: filter by muscle group, watch animated demonstrations, read technique instructions, and create custom exercises.

6.6 Connections

• Your plan’s day types drive the Food tab’s daily targets (carb cycling).
• Workouts sync with Apple Health and the Watch app; Watch-recorded workouts appear in My Plan for import.

Note: The training module includes an exercise disclaimer — Subten provides guidance, not medical advice. Stop any exercise that causes pain.

7 Progress

7.1 What it is for

The Progress tab tracks the outcome: weight, trend, body composition, measurements and photos.

7.2 The screen

• Weight hero card — current weight and an add weight button. Log at a consistent time (mornings work best).
• Weight chart — with selectable ranges. The trend, not any single weigh-in, is what the adaptive engine uses.
• Body composition and Body measurements — log waist, hips, arms and more, each tracked over time.
• Streak and Progress photos — consistent photos (same light, same pose) are often more motivating than the scale.

7.3 Common mistakes

• Weighing once a week and panicking. Daily weight fluctuates 1–2 kg with water and food timing. Weigh often, judge the trend line, ignore single readings.

8 Coach (AI mentor)

8.1 What it is for

The Coach tab is your AI mentor: a chat that knows your data and four one-tap reviews. It explains, suggests and — with your confirmation — acts.

Note: As required by the EU AI Act, the Coach discloses that you are communicating with an AI mentor. It is not a doctor, nutritionist or trainer; for medical concerns see a professional.

8.2 The screen

• Chat — streaming replies; you can edit a message, retry, copy, stop generation, or start a new chat. Suggestion chips adapt to the time of day.
• Four tiles — Daily review, Weekly Review (7-day charts of recovery, weight trend, calorie compliance, macro averages and training, plus an AI insight), Meal plan, Shopping list.
• Plateau banner — when your progress stalls, the Coach offers a deep-dive analysis.
• Action cards — the Coach can propose logging a food or an activity for you; nothing is logged until you confirm.

8.3 On-device AI (Private mode)

Subten can run the Coach’s text features (chat, the daily and weekly reviews, plateau analysis) directly on your iPhone — without sending anything to the cloud. This happens automatically; you don’t switch anything on.

How to tell in chat: when a Coach reply runs on the device, the conversation header shows a badge with a lock and the word “On-device”. When that badge is absent, the reply was handled by the cloud. Simple rule: lock = on-device, no lock = cloud.

The local model is only available on iPhones with 6 GB of RAM or more. On weaker devices (under 6 GB) the Coach always uses the cloud and the “On-device” badge never appears.

First model download (Wi-Fi only)

For on-device AI to work, Subten needs a language model (~3 GB). The fine-tune adapter ships inside the app, but the base model itself is downloaded after install, like this:

• The download runs in the background at app launch — no screen, no progress bar, nothing you have to do.
• It downloads over Wi-Fi (or ethernet) only. On cellular it is skipped and retried at the next launch on Wi-Fi.
• Until the model is downloaded and loaded, the Coach uses the cloud (and the “On-device” badge doesn’t show). Once it’s ready, Subten switches to the local model automatically.
• The download is interruptible and resumable — if it stops, it finishes later, and already-downloaded parts are not fetched again. The model is kept out of your (iCloud) backup.

In practice: after the first install, leave the phone on Wi-Fi for a while and on-device AI prepares itself. Until then the app works normally, just via the cloud.

When the local model runs, and when the cloud does

Subten decides automatically — you don’t switch anything. The local (on-device) model is used when all three conditions hold at once:

• it is a Coach text feature: chat, the daily review, the weekly review or the plateau analysis;
• the app language is Slovak, Czech or English;
• the local model has been downloaded and loaded into memory (iPhone with 6 GB of RAM or more).

In that case the reply carries the on-device badge and nothing leaves the phone. In every other case the cloud (OpenRouter API) is used:

* If local generation fails, Subten silently falls back to the cloud so you still get an answer (except in Private mode).

Private mode (optional toggle)

On iPhones with 6 GB of RAM or more, Settings has a Private mode: AI on device only toggle. The normal (automatic) behaviour already prefers the device; this toggle additionally disables the cloud fallback for the Coach’s text features — if the local model can’t answer, it shows an honest error rather than sending data to the cloud. Offline behaves the same as Private mode.

Even in Private mode, cloud features stay in the cloud: food, label and recipe scans, AI food estimation and meal plans (which send your photos) — these simply won’t run without the cloud.

8.4 Availability

The Coach is a Premium feature; without Premium the tab shows an unlock card.

9 Part IV — The adaptive engine

This chapter explains, in user terms, how your targets change over time. You don’t need to do anything for this to work — just log food and weigh-ins.

9.1 Calibration (first ~2 weeks)

The engine will not touch your targets until it has: at least 14 days of history, at least 10 days with logged intake, and at least 3 weigh-ins. Until then the Today tab shows the calibration banner. The starting targets are deliberately conservative.

9.2 Weekly adaptation

Every 7 days the engine measures your true maintenance from real data: your average intake and your actual weight trend together reveal how much you really burn. Your new daily goal is that measured maintenance plus your goal’s deficit or surplus. Safety rails:

• Targets move by at most ±250 kcal per week (up to +400 for muscle gain), so no whiplash.
• A brake engages if you lose faster than 1 % of body weight per week — the engine nudges calories up to protect muscle.
• Refeed, cheat, plateau and diet-break days (and a short buffer after them) are excluded; diet-break weeks are skipped entirely.
• A hard calorie floor (sex-based) is never crossed.

When targets change you’ll see the Adapted this week badge on the Today tab, and the Coach can explain the change.

9.3 Time to goal (ETA)

Your ETA is recomputed from the measured trend. It can read collecting data, no clear trend, goal reached, or an actual date. If the current trend would take longer than about two years, the app caps the estimate rather than display fiction.

9.4 Strategies

Settings → Advanced → Life situations & Strategies (and the strategy hub) offer planned protocols:

Using the built-in strategies (instead of ad-hoc off-plan days) keeps your data clean and your adaptation accurate.

10 Part V — Apple Watch & shortcuts

10.1 The Watch app

The Subten Apple Watch app is an optional bonus — a convenient glance at your day right on your wrist (rings, water, complications). It is not required to use Subten: the health data (recovery, sleep, heart rate…) is read from Apple Health independently of it, so any other brand of watch or wearable sensor that feeds Apple Health works just as well (see chapter 11).

The Watch home screen mirrors your day:

• Concentric rings — calories plus protein, carbs, fat and fiber; the centre shows remaining (or over, in red).
• Energy card and compact macro bars.
• Recovery row — when recovery data exists, tap through for the detail.
• Water button — tap for +250 ml, long-press for other doses.

10.2 Complications and widgets

Add the Subten complication to your watch face for at-a-glance remaining calories; the iPhone widget does the same on your home screen.

10.3 Action Button and Siri

On iPhone 15 Pro and newer you can map the Action Button to Subten’s Add food or Scan food intent. The same intents work with Siri and the Shortcuts app; the Watch adds a Log Water intent.

11 Part VI — Apple Health

Subten asks for Health access only when you explicitly enable it (onboarding step 6 or Settings → Health). You control each type separately.

Subten reads whatever is in Apple Health, regardless of which device wrote it. An Apple Watch is not required — anything that feeds Apple Health works: an Apple Watch, Garmin, Oura, Whoop, other bands and rings, or the iPhone itself (steps, sleep). The more data Apple Health holds, the more accurate recovery and recommendations are; without it Subten still works, those features just stay empty.

Health alerts: when the data shows anomalies (unusual SpO₂, respiratory rate, heart rate, HRV, temperature or sleep), Subten surfaces a banner on the Today tab. These are informational nudges, not diagnoses.

Tip: If numbers look doubled (e.g. a workout counted twice), check that only one app writes workouts, or disable that type’s sync in Settings → Health → Sync by type.

12 Part VII — Premium & subscription

12.1 Free vs Premium

12.2 Subscribing

The paywall offers Monthly and Yearly plans (Yearly is marked Best value with a per-month breakdown) with a free-trial period. Purchases go through your Apple ID; subscriptions auto-renew until cancelled in iOS Settings. Restore purchases recovers an existing subscription on a new device. A promo code field accepts codes.

12.3 Trial

A local free trial starts when you finish onboarding. When it ends, AI and premium training features lock again and the app shows Trial expired — Activate Premium. Your data is never locked away: logging, progress and export stay free.

13 Part VIII — Settings, privacy & account

Open Settings from the gear on the Today tab.

13.1 Your data

• Export & Import (free, GDPR): export everything to a file, import it on another device or after reinstalling.
• Delete account & data wipes the server, the device and iCloud. This is irreversible — export first if in doubt.
• AI consent: AI features that use the cloud only run with your explicit consent, controllable in AI in Subten. Private mode (§8.3) keeps coaching fully on-device.

14 Part IX — Troubleshooting & FAQ

A banner says “Food database failed to load.” Tap Retry. If it persists, force-quit and reopen the app.

My photo scan is stuck “pending.” Scans queue offline and process automatically once you’re online. Open the scan queue from the banner to retry failed items.

Prices don’t load on the paywall. Price unavailable, try again later means the App Store didn’t respond — tap Retry, check your connection.

My targets haven’t changed in weeks. Check you meet the calibration minimums (§9.1): enough logged days and at least 3 weigh-ins in the window. Diet-break weeks are skipped by design.

Remaining doesn’t grow when I exercise. By design — see the energy model (§2.2).

Steps/weight don’t sync. Check Settings → Health: the master toggle and the per-type switch. Then check iOS Settings → Privacy & Security → Health → Subten.

I changed the language but the app is mixed. Restart the app — the language switch requires it.

The Coach tab just shows an unlock card. The Coach is Premium; start the trial or subscribe. If you are Premium, tap Restore purchases on the paywall.

I can’t select my birth date. Subten is 18+; the picker enforces it.

Deleting my account failed. You need a network connection (the server copy must be wiped too). Try again online; contact support via Settings → Feedback if it persists.

15 Appendix — Glossary

Subten — User Manual · v1.0 · © 2026