fud-ai

Introduction: Fud AI is a Free & Open Sourced AI Calorie Tracker for iOS & Android

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Fud AI

Eat Smart, Live Better
Snap, speak, or type your food — AI handles the rest.

Open-source, privacy-first calorie tracker for iOS and Android. Bring your own AI provider — 13 supported including Gemini, OpenAI, Claude, Grok, Groq, Hugging Face, Fireworks AI, DeepInfra, Mistral, and any custom OpenAI-compatible endpoint. Capture or import up to 10 food photos with an optional note, scan a barcode, ask your AI coach how to hit your goal, speak your lunch, or use Siri Shortcuts on iOS to log food and weight. On supported iPhones, food-description analysis for text, voice-transcribed, and Siri food logs can use Apple Intelligence on-device as the final fallback after BYOK provider/fallback attempts fail. No accounts, Fud AI cloud sync, tracking, or ads — completely free.

iOS and Android 6.1 (build/versionCode 34) add an optional intermittent-fasting tracker alongside the existing nutrition and workout tools. Choose a goal from 1–168 hours, start, end, or cancel a fast from the Home + menu, keep the timer across app restarts, and review or edit completed sessions. Goal alerts are optional local notifications, and fasting remains separate from calories, macros, Apple Health, and Health Connect.

The app also includes faster Saved Meal reuse, current-time meal copying, export of every stored nutrient, selectable water units, water progress on Apple Watch, current AI model presets, configurable timeouts for Ollama/custom endpoints, and reliability fixes across widgets, settings, images, and provider responses. Normal updates preserve existing local and Health data.

App Store · Google Play · Website · Report an Issue · Request a Feature

Logging

Photo & Scan menu — a focused submenu for Camera, Photos, and Barcode
Multi-photo Camera — keep taking photos, review them horizontally, add an optional note, then analyze up to 10 separate images together
iOS Share Extension — send a food photo from Photos or another app directly into Fud AI for review and logging
Barcode lookup — scan packaged foods on iOS and Android and fill nutrition from Open Food Facts when product data is available
Multi-photo library import — select up to 10 existing images, add an optional note, and analyze them together
Text input — type food descriptions
Voice input — speak your meals hands-free (6 STT options with per-provider language selection, see below)
iOS Siri Shortcuts — say phrases like "Log food in Fud AI", "Calories today in Fud AI", or "Log my weight in Fud AI"; the phrase guide lives under + → Describe Meal → Siri Phrases
Manual Entry — log known calories and macros without AI
Smart serving units — AI can show slices, pieces, cups, ml, or other visible serving units while grams stay the source of truth
Review nutrition unlock — correct calories, macros, and detailed nutrients before logging, then lock again so serving changes scale from your edits
Meal What if? — preview how a reviewed meal changes today's calories and macros, then ask AI for a practical suggestion before logging
Saved Meals — Recents, Frequent, and Favorites with safer swipe actions, search, and drag-to-reorder
Retryable analysis — failed image analysis offers Retry and Cancel without limiting the number of retries

Intelligence

AI Coach tab — multi-turn chat with memory. Coach can retrieve relevant profile, weight, body-fat, nutrition, workout, and explicitly logged fasting context, then answer questions like "what's my expected weight in 30 days?" or "how did my training go this week?". It never treats a missing meal log as proof that you fasted. Camera/photo attachments work on both platforms. Memory persists across launches; Reset starts a fresh conversation. Long-press any reply to copy.
AI Access — free Bring Your Own Key: pick provider, model, fallback, custom instructions, and speech language directly on device. (The optional Fud AI Premium proxy from earlier iOS versions has been discontinued.)
Apple Intelligence fallback — on supported iPhones, food-description analysis for text, voice-transcribed, and Siri food logs can use Apple Intelligence on-device as the final fallback after BYOK provider/fallback attempts fail.
AI optional nutrient goals — estimate detailed nutrient goals from profile data without changing calorie/protein/carbs/fat formulas.
Goal-aware prompt chips — suggested questions change based on whether your goal is Lose / Gain / Maintain
Thermodynamic weight forecast — expected weight at 30/60/90 days, predicted vs observed weekly change, days-to-goal, under-logging detection. Surfaced through Coach as live context on every turn.
Resilient requests — transient provider overloads (503 / 529 / 429) auto-retry with 1s / 2s / 4s exponential backoff across both food analysis and Coach chat, so short spikes resolve invisibly

Tracking

Expanded nutrients per entry — macros plus sugar, fiber, fats, cholesterol, sodium, potassium, calcium, iron, magnesium, zinc, vitamins, folate, omega-3, and more when available
Custom Home nutrient cards — swap the top cards from protein/carbs/fat to fiber, sodium, vitamin D, calcium, or other tracked nutrients
Optional nutrient goals — set or AI-estimate goals for the non-macro nutrients; these stay separate from the calorie and macro calculator
Scrollable week calendar — swipe to any past week, configurable start day
Food log sorting — keep the default grouped view, or sort meal sections by latest logging order from the Home screen
Progress charts — weight trends, calorie history, macro averages (1W to All Time)
Progress summaries — weight and body-fat ranges show average and net change for the selected week, month, or longer window
Decimal nutrition totals — macros and detailed nutrients preserve decimal precision in logs, Home, widgets, and View More
Weight History — tap-to-delete past entries and sync supported deletions to Apple Health / Health Connect
Goal tracking — set target weight, BMR/TDEE auto-calculation; goal-reached alert fires from both manual logs and Apple Health reads
Adaptive Goals — weekly calorie correction from observed weight trend; pinned macros stay pinned and unlocked macros auto-balance. On by default for new installs (stays off if you hand-edit your plan during onboarding)
Six activity levels — Sedentary, Light, Moderate, Active, Very Active, and Extra Active use work and training descriptions instead of step-count requirements
Custom meal times — choose when Breakfast, Lunch, Dinner, and Snack begin; the app uses those boundaries for automatic meal grouping
Optional water tracking — off by default; set any practical daily goal, quick-log one to three glasses or a custom amount, see progress below calories, and optionally schedule a local reminder
Optional fasting tracking — off by default; choose a 1–168 hour goal, start/end/cancel from the Home + menu, keep an active timer through app restarts, optionally receive a local goal alert, and edit or delete completed sessions without changing nutrition totals

Workouts

Workout diary & logger — plan exercises by day, swipe between weeks, and log sets, reps, weight, and RPE without starting a timer
Calculated workout burn — estimate a day's calorie burn from the logged work, review or delete burn history in Progress, and optionally sync those records with Apple Health / Health Connect
Exercise library — switch in place to 873 exercises with photos, primary/secondary muscle and equipment filters, search, sort, and per-exercise detail pages; the last diary/library view persists
Coach workout context — Coach can retrieve workout plans, preferences, completed sessions, sets, reps, RPE, and calculated burn when answering training questions

Health & platform

Apple Health — bidirectional sync for body measurements, meal nutrition, and calculated workout calories; Siri food/weight logs use the same HealthKit paths, and Energy Burn Goals can estimate calorie targets from active/total energy while macros stay editable
Health Connect — Android sync for nutrition, weight, body fat, and calculated workout calories, with permission reconciliation and backfill support; Energy Burn Goals can use recent energy data for calorie targets
Local-only fasting records — fasting sessions are intentionally not written to Apple Health or Health Connect; eligible OS backup/device transfer may still include them according to device settings
Restore after a reinstall — on a fresh install or new phone, food, weight, body-fat, and calculated workout-burn records previously written by Fud AI can restore from Apple Health / Health Connect; local workout plans and set details require an OS backup/device transfer
Apple Watch — watchOS app and complications show calories, macros, and compact water progress when water tracking is enabled
Widgets — iOS offers Fud AI in Small, Medium, and Large, small Protein, and a separate small/Lock Screen Water widget; Android offers Calorie, Protein, Today, and Water Glance widgets that update from local snapshots
Share the App — native iOS share sheet from About → forwards App Store URL plus a personalized message and fud-ai.app link; message body localized into all 16 iOS languages
Update check — About shows the installed app version, opens the App Store / Play Store when a newer version is available, and shows a tab dot for pending updates
Theme color — iOS and Android Settings let users change the app accent, with matching home screen / launcher icons
Languages — iOS supports 16 languages: Arabic, Azerbaijani, Dutch, English, French, German, Hindi, Italian, Japanese, Korean, Polish, Portuguese (Brazil), Romanian, Russian, Simplified Chinese, Spanish. Android supports the same set except Polish. The app auto-selects by the phone's Language setting.
Meal reminders — customizable breakfast, lunch, dinner notifications
Dark mode — system, light, or dark
Metric & imperial units

AI Providers

Pick any of the 13 LLM providers for food analysis, meal what-if suggestions, optional nutrient-goal estimation, and Coach chat. Free Gemini keys are available at aistudio.google.com/apikey. Requests go directly from your device to the provider you configure. For text, voice-transcribed, and Siri food descriptions on supported iPhones, Apple Intelligence can run on-device only as the last fallback after BYOK provider/fallback attempts fail.

Provider	Format	Highlight	Needs API Key
Google Gemini	Gemini API	Gemini 3.5 Flash-Lite (default) / 3.6 Flash / 3.5 Flash	Yes
OpenAI	OpenAI	GPT-5.4 Mini (default) / 5.5 / 5.4 Nano	Yes
Anthropic Claude	Messages API	Sonnet 5 (default) / Opus 4.8 / Haiku 4.5	Yes
xAI Grok	OpenAI-compatible	Grok 4.3	Yes
OpenRouter	OpenAI-compatible	Any model, free-form IDs	Yes
Together AI	OpenAI-compatible	Qwen 3.5, Gemma 4, MiniMax M3	Yes
Groq	OpenAI-compatible	Qwen 3.6, very fast	Yes
Hugging Face	OpenAI-compatible	Gemma 4 / 3 and Qwen 3.5 / 2.5 VL (open-weight router, free-form IDs)	Yes
Fireworks AI	OpenAI-compatible	Qwen 3.7 Plus, MiniMax M3, Kimi K2.6	Yes
DeepInfra	OpenAI-compatible	Gemma 4 / 3 vision models	Yes
Mistral	OpenAI-compatible	Mistral Small / Medium, Ministral 14B	Yes
Ollama	OpenAI-compatible (local)	Qwen 3 VL, Gemma 4, Llama 3.2 Vision, LLaVA, Moondream	No
Custom (OpenAI-compatible)	OpenAI-compatible	You set base URL + free-form model name	Optional

Speech-to-Text Providers

Pick how voice input is transcribed. Native iOS / Android is the default — free, on-device where supported, real-time. On Android, native speech first tries the on-device language path, then falls back to Android recognition with network/provider defaults if the phone lacks offline support for that language. Each provider has its own language setting: use Provider Auto, Use Device Language, or an explicit language hint where supported.

Provider	Notes
Native iOS / Android (On-Device)	Free, offline where the phone supports the selected language, real-time partial results
Gemini Audio	Batch audio transcription through Gemini for BYOK users
OpenAI Whisper	Whisper-1 via `/v1/audio/transcriptions`
Groq (Whisper)	Whisper-large-v3, very fast, has a free tier
Deepgram	Nova-3, fast and accurate
AssemblyAI	Universal model, strong accuracy, free tier

For Android phones where native speech is inconsistent, Groq (Whisper) or Deepgram are recommended alternatives; the developer currently uses Groq.

API keys are stored encrypted on-device: iOS Keychain on iOS and EncryptedSharedPreferences backed by Android Keystore on Android.

How It Works

Photo(s) / Text / Voice
        │
        ▼
  BYOK provider API
        │
        ├── BYOK provider fallback if configured
        └── iOS Apple Intelligence final fallback for text / voice transcript / Siri food descriptions
        │
        ▼
  JSON nutrition response
        │
        ▼
  User reviews & edits
        │
        ▼
  FoodStore.addEntry()  ──▶  UserDefaults (local) + Apple Health (optional)

For the Coach chat, every turn builds a slim system prompt from your live profile, BMR formula in use, computed forecast, today's date/timezone, and a one-line snapshot of available data. Coach then pulls relevant ranges of weight, body fat, calorie totals, food entries, workouts, or explicitly logged fasting sessions on demand via tool calling — ask "what was my weight in March?" or "how did my completed fasts line up with training this week?" and it fetches only the slice it needs. Coach never infers fasting from gaps in the food log.

Screenshots

An eight-screen walkthrough of the current app flow — from the dashboard and grouped logging menu through review, progress, Coach, and Workouts.

01 · Home · Dashboard _{Daily calorie ring, selected Home nutrient cards, and today's logged meals grouped by meal type. Week strip at the top for date navigation.}	02 · Log · Options _{Tap + for Photo & Scan, Describe Meal, Reuse Meal, and optional Water groups. Camera and Photos accept up to 10 images plus an optional note.}	03 · Snap · Capture _{Point and shoot. The image is sent to your chosen AI provider; nutrition estimates come back within a few seconds.}
04 · Review · Edit _{Review the AI's guess, unlock nutrition if values need correction, adjust the serving size (everything recalculates live), preview "What if?" impact, and pick a meal type before logging.}	05 · Meals · Log _{The day's entries grouped by breakfast / lunch / dinner / snack. Swipe to delete, tap to edit any entry.}	06 · Coach · AI Chat _{Multi-turn conversation with full context of your profile, weight history, food log, and forecast. Ask "what should I eat?" or "expected weight in 30 days?".}
07 · Progress · Charts _{Weight trend with goal line, calorie history (intake vs. goal), and macro averages. Time ranges span 1 week to all time.}	08 · Workouts · Library _{Browse 873 exercises with photos, filterable by primary/secondary muscle and equipment, with search, sort, and per-exercise detail pages.}

Calorie & Macro Calculation

The app calculates personalized daily targets using established nutrition science formulas:

Step	Formula	Details
BMR	Katch-McArdle	`370 + 21.6 × lean mass (kg)` — used when body fat % is known
BMR	Mifflin-St Jeor	`10w + 6.25h − 5a ± 5` — fallback when body fat is unknown
TDEE	BMR × activity	Multiplier ranges from 1.2 (sedentary) to 1.9 (extra active)
Daily Calories	TDEE + adjustment	Adjustment = `weeklyChangeKg × 7700 / 7` (deficit or surplus)
Protein	Activity + goal	`0.8 – 2.2 g/kg` body weight by activity, plus +0.2 g/kg during cutting phase (Helms et al 2014); when body fat % is known, Activity Level also shows the equivalent g/kg lean-mass multiplier
Fat	Fixed ratio	`0.6 g/kg` body weight
Carbs	Auto-balanced	Remainder from calories − protein − fat (any macro can be pinned; max 2 pinned)

All values can be manually overridden in Settings, with a Recalculate Goals button to snap back to formula defaults.

Architecture

Component	Details
Language	Swift 5, SwiftUI, iOS 17.6+
Storage	UserDefaults (local JSON), Keychain (API keys)
AI	`GeminiService` for food + label analysis, `ChatService` for multi-turn Coach chat, both route across all 13 providers
Speech	Native `SFSpeechRecognizer` / Android `SpeechRecognizer` or remote providers via `SpeechService` (m4a upload)
Health	HealthKit / Health Connect read-write paths for body measurements, meal nutrition, and calculated workout calories, with UUID-tagged samples for safe delete
Pattern	`@Observable` + `.environment()`, main actor isolation
Localization	`Localizable.xcstrings` (String Catalog), 16 iOS languages, auto-selected by iPhone's system language
Dependencies	Native platform frameworks; app data and API keys remain local

Repo Layout

fud-ai/
├── ios/          # SwiftUI iOS app (v6.1 build 34)
├── android/      # Kotlin + Jetpack Compose app (min SDK 26 / Android 8.0, v6.1 / versionCode 34)
├── web/          # Marketing site — https://fud-ai.app (static HTML/CSS, Cloudflare Workers)
├── APPSTORE.md   # App Store Connect listing copy (iOS)
├── PLAYSTORE.md  # Google Play Console listing copy (Android)
└── README, LICENSE, CONTRIBUTING, SECURITY, .github/

Source Layout (iOS)

ios/
├── calorietracker.xcodeproj/         # Xcode project
├── calorietrackerTests/              # Unit test target (boilerplate)
├── calorietrackerUITests/            # UI test target (boilerplate)
├── FudAIWidgets/                     # Widget extension target (Home + Lock Screen)
├── screenshots/                      # App Store screenshot sources
└── calorietracker/
    ├── calorietrackerApp.swift       # Entry point, environment setup
    ├── ContentView.swift             # 5-tab layout (Home, Progress, Coach, Settings, Workouts)
    ├── Localizable.xcstrings         # String Catalog, 16 languages
    ├── Models/
    │   ├── AIProvider.swift          # 13 LLM providers, model lists, settings
    │   ├── SpeechProvider.swift      # 6 STT options + Keychain settings
    │   ├── ChatMessage.swift         # Coach chat message model
    │   ├── UserProfile.swift         # BMR/TDEE/macro calculations
    │   ├── FoodEntry.swift           # Food item with macros and expanded optional nutrients
    │   └── WeightEntry.swift         # Weight log entry
    ├── Views/
    │   ├── OnboardingView.swift      # 15-step onboarding flow
    │   ├── ChatView.swift            # Coach tab: bubbles, prompt chips, reset
    │   ├── FoodResultView.swift      # AI result review & edit
    │   ├── RecentsView.swift         # Saved Meals (Recents / Frequent / Favorites)
    │   ├── VoiceInputView.swift      # Native + remote STT routing
    │   ├── HomeComponents.swift      # Week strip, macro cards
    │   └── ProgressComponents.swift  # Charts, weight history
    ├── Services/
    │   ├── GeminiService.swift       # Food/label analysis, routes 13 providers
    │   ├── ChatService.swift         # Multi-turn Coach chat, routes 13 providers
    │   ├── SpeechService.swift       # Remote STT router (Gemini / OpenAI / Groq / Deepgram / AssemblyAI)
    │   ├── WeightAnalysisService.swift # Thermodynamic weight-forecast math
    │   ├── KeychainHelper.swift      # iOS Keychain wrapper
    └── Stores/
        ├── FoodStore.swift            # Food CRUD + favorites
        ├── WeightStore.swift          # Weight CRUD (auto-syncs profile weight)
        ├── ProfileStore.swift         # @Observable wrapper over UserProfile
        ├── ChatStore.swift            # Coach chat history (persisted locally)
        ├── NotificationManager.swift  # Local notification scheduler, including optional water reminders
        ├── WaterStore.swift           # Local water entries and daily goal
        ├── StrengthWorkoutStore.swift # Local workout diary, sets, and burn history
        └── HealthKitManager.swift     # Apple Health bridge (body + nutrition + workout burn)

Build & Run

# Clone
git clone https://github.com/apoorvdarshan/fud-ai.git
cd fud-ai

iOS

xcodebuild -project ios/calorietracker.xcodeproj \
  -scheme calorietracker \
  -destination 'platform=iOS Simulator,name=iPhone 17 Pro' build

Open ios/calorietracker.xcodeproj in Xcode, select your device, and run.

Android

Open android/ in Android Studio (Narwhal or newer), let Gradle sync, hit ▶ Run. Or from the CLI:

export JAVA_HOME="/Applications/Android Studio.app/Contents/jbr/Contents/Home"
cd android
./gradlew :app:assembleDebug
adb install -r app/build/outputs/apk/debug/app-debug.apk
adb shell am start -n com.apoorvdarshan.calorietracker/.MainActivity

First launch walks you through onboarding (gender, birthday, height/weight with metric/imperial toggle, body fat %, one of six activity levels with a protein-target preview, goal, goal speed, notifications, Apple Health / Health Connect, AI access setup, and review). A free Gemini key is available at aistudio.google.com/apikey. You can change provider anytime in Settings → AI Access.

Contributing

See CONTRIBUTING.md for guidelines. Bug reports and feature requests welcome.

Adding a new translation? Open ios/calorietracker/Localizable.xcstrings in Xcode and fill in your language column — everything else is already wired.

Security

See SECURITY.md. Use private vulnerability reporting for sensitive issues.

Privacy

No accounts, Fud AI-operated cloud sync, or analytics. BYOK API keys are protected by iOS Keychain or Android EncryptedSharedPreferences, and requests go directly to the provider you choose. Food, weight, body-fat, water, fasting, and workout logs, custom meal times, goals, preferences, cached images, and widget/Watch snapshots are local except for OS backup/device transfer and the specific AI/STT, barcode, health-sync, update-check, export, or sharing action you initiate. When Coach is used, it may send explicitly logged fasting context to your selected AI provider, but it never infers fasting from missing meals. Shared meal links carry the selected meal details in the URL, so anyone with the link can read them. Apple Health / Health Connect access is optional and can be reviewed or revoked through Manage Access; fasting is not synced to either health store. Delete All Data wipes the current local installation, including saved keys, water and fasting history, and workout plans/history, but never removes Apple Health, Health Connect, or older OS backups. See the complete Privacy Policy.

License

MIT License. See LICENSE.

Contact

Developer: Apoorv Darshan
Email: apoorv@fud-ai.app or ad13dtu@gmail.com
Follow on X: @apoorvdarshan
Follow on Instagram: @fudai.app
Follow on LinkedIn: Fud AI
View on TrustMRR: Fud AI - Calorie Tracker
Report an Issue: github.com/apoorvdarshan/fud-ai/issues/new?labels=bug&title=Bug:%20
Request a Feature: github.com/apoorvdarshan/fud-ai/issues/new?labels=enhancement&title=Feature:%20

Support the Project

Fud AI is fully free, open source, and privacy-first — no ads, no subscription. If it helps you, consider supporting development (on iOS there's an in-app Tip Jar under Settings → About) — every bit keeps this project alive.