fud-ai

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

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Fud AI Logo

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. iOS also supports Fud AI Plus, an optional paid no-key mode that routes food scans and Coach through Gemini and Plus voice through Deepgram via a serverless proxy with daily limits and speech language control. Snap a meal, scan a barcode, combine two camera shots, add a note to a camera or library photo, ask your AI coach how to hit your goal, or speak your lunch. No accounts, no cloud sync, no tracking.

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

Logging

Snap food — camera identifies meals and estimates nutrition
Camera + Note — add a description with the photo for better accuracy
Camera + Camera — capture two images for one analysis, useful for front/back packaging or food + label combos
Nutrition label scan — reads packaging for precise per-serving data
Barcode lookup — scan packaged foods on iOS and Android and fill nutrition from Open Food Facts when product data is available
Photo library — analyze existing photos
Photo library + Note — pick an existing photo and add context before AI analysis
Text input — type food descriptions
Voice input — speak your meals hands-free (6 STT options with per-provider language selection, see below)
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
Saved Meals — Recents, Frequent, and Favorites with safer swipe actions, search, and drag-to-reorder

Intelligence

AI Coach tab — multi-turn chat with memory. Coach sees your profile, weight history, food log, today's date/timezone, and richer meal details, then answers questions like "what's my expected weight in 30 days?" or "how do I lose 2 kg?". Coach also supports camera/photo attachments on Android. Memory persists across launches; Reset button starts a fresh conversation. Long-press any reply to copy.
AI Access modes — Bring Your Own Key remains available; iOS onboarding now highlights optional Fud AI Plus first for no-key Gemini food scan, Deepgram voice transcription, and Coach access with a Plus speech language selector.
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)
Weight History — tap-to-delete past entries, syncs deletion to Apple Health
Goal tracking — set target weight, BMR/TDEE auto-calculation; goal-reached alert fires from both manual logs and Apple Health reads

Health & platform

Apple Health — bidirectional sync for body measurements + nutrition types written per meal
Health Connect — Android sync for nutrition, weight, and body fat, with permission reconciliation and backfill support
Widgets — Home Screen and Lock Screen widgets on iOS now follow your selected Home nutrient cards instead of fixed macros; Android Glance widgets update when you log
Android 2.0 UI refresh — cleaner glass-style menus, sheets, dialogs, selectors, light mode, bottom spacing, cached thumbnails, in-app camera capture, and safer food-row gestures
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 15 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
15 languages — Arabic, Azerbaijani, Dutch, English, French, German, Hindi, Italian, Japanese, Korean, Portuguese (Brazil), Romanian, Russian, Simplified Chinese, Spanish (auto-selected 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, optional nutrient-goal estimation, and Coach chat. Free Gemini keys are available at aistudio.google.com/apikey. On iOS, Fud AI Plus can be selected instead of BYOK; Plus uses Gemini models for food and Coach behind a serverless proxy, Deepgram for voice transcription, and separate daily limits for food analysis, speech-to-text, and Coach. Plus voice can use Provider Auto, which follows the iPhone language, or a manually selected speech language. Plus currently offers weekly, monthly, and yearly products.

Fud AI Plus proxy env vars: GEMINI_API_KEY is required for food/Coach, and DEEPGRAM_API_KEY is required for Plus voice. Optional quota overrides are FUD_AI_PLUS_FOOD_DAILY_LIMIT, FUD_AI_PLUS_SPEECH_DAILY_LIMIT, FUD_AI_PLUS_COACH_DAILY_LIMIT, and FUD_AI_PLUS_GLOBAL_DAILY_LIMIT. Defaults are 30 food analyses, 20 speech transcriptions, 25 Coach messages, and 70 total successful Plus calls per day. Plus voice recordings are capped at 60 seconds in the app.

Provider	Format	Highlight	Needs API Key
Google Gemini	Gemini API	Gemini 2.5 Pro / Flash	Yes
OpenAI	OpenAI	GPT-5 / 4o	Yes
Anthropic Claude	Messages API	Sonnet 4.6 (default) / Opus 4.7 / Haiku 4.5	Yes
xAI Grok	OpenAI-compatible	Grok 4	Yes
OpenRouter	OpenAI-compatible	Any model, free-form IDs	Yes
Together AI	OpenAI-compatible	Llama 4, Qwen VL	Yes
Groq	OpenAI-compatible	Llama 4 Scout, very fast	Yes
Hugging Face	OpenAI-compatible	Gemma 3, Qwen VL, Llama Vision (open-weight router, free-form IDs)	Yes
Fireworks AI	OpenAI-compatible	Qwen VL, Llama Vision, Phi-3 Vision	Yes
DeepInfra	OpenAI-compatible	Gemma 3, Llama Vision, Qwen VL	Yes
Mistral	OpenAI-compatible	Pixtral Large / 12B (open-weight)	Yes
Ollama	OpenAI-compatible (local)	Llama 3.2 Vision, LLaVA, Moondream — runs on your Mac	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 is the default — free, on-device, real-time. Each provider has its own language setting: use Provider Auto, Use iPhone Language, or an explicit language hint where supported.

Provider	Notes
Native iOS (On-Device)	Free, offline on modern iPhones, 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; used by Fud AI Plus voice logging through the proxy
AssemblyAI	Universal model, strong accuracy, free tier

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

How It Works

Photo / Text / Voice
        │
        ▼
  BYOK provider API or Fud AI Plus proxy  ──▶  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 any date range of weight, body fat, calorie totals, or food entries on demand via tool calling — ask "what was my weight in March?" or "show me my body fat trend over the last 6 months" and it fetches exactly the slice it needs, including meal source, meal type, serving size, and micronutrients.

Screenshots

An eight-screen walkthrough of the current app flow — from opening the dashboard to detailed nutrition and progress.

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 + to open Camera, Camera + Note, Camera + Camera, Nutrition Label, Barcode, Photos, Text, Voice, Manual Entry, Saved Meals, or Copy from Day.}	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, adjust the serving size (everything recalculates live), 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 · View More · Nutrients _{Detailed nutrition shows macro totals plus optional nutrients such as fiber, sugar, sodium, minerals, vitamins, and fats.}

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 2.0 (extra active)
Daily Calories	TDEE + adjustment	Adjustment = `weeklyChangeKg × 7700 / 7` (deficit or surplus)
Protein	Activity + goal	`0.8 – 2.2 g/kg` by activity, plus +0.2 g/kg during cutting phase (Helms et al 2014)
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` or remote providers via `SpeechService` (m4a upload)
Health	HealthKit / Health Connect read-write paths for body measurements and meal nutrition, with UUID-tagged samples for safe delete
Pattern	`@Observable` + `.environment()`, main actor isolation
Localization	`Localizable.xcstrings` (String Catalog), 15 languages, auto-selected by iPhone's system language
Dependencies	RevenueCat SPM for iOS purchases; app data and API keys remain local

Repo Layout

fud-ai/
├── ios/          # SwiftUI iOS app (shipping on App Store, v3.6)
├── android/      # Kotlin + Jetpack Compose app (min SDK 26 / Android 8.0, v2.0.0)
├── web/          # Marketing site — https://fud-ai.app (static HTML/CSS, Vercel)
├── APPSTORE.md   # App Store Connect listing copy (iOS)
├── PLAYSTORE.md  # Google Play Console listing copy (Android)
└── README, LICENSE, CONTRIBUTING, SECURITY, CLAUDE.md, .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, About)
    ├── Localizable.xcstrings         # String Catalog, 15 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
    │   └── APIKeyManager.swift       # Keychain migration helper
    └── 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  # Notification scheduler
        └── HealthKitManager.swift     # Apple Health bridge (body + nutrition)

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 a 15-step onboarding (gender, birthday, height/weight with metric/imperial toggle, body fat %, activity, goal, goal speed, notifications, Health Connect, AI access mode, plan preview, review). A free Gemini key is available at aistudio.google.com/apikey, or iOS users can choose Fud AI Plus. You can switch 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, no cloud sync, no analytics. BYOK API keys are encrypted on-device and requests go directly to the provider you choose. Barcode lookup sends the scanned barcode to Open Food Facts and stores the returned nutrition locally. Fud AI Plus sends only the active AI/STT request through the proxy for processing and quota enforcement: Gemini for food/Coach and Deepgram for voice. Optional nutrient goals, Home nutrient-card choices, food photos, cached thumbnails, and widget snapshots are local preferences/data; AI estimation sends only the profile context needed for that one estimate. Delete All Data is local-only — it wipes the app's storage (food log, weight log, body-fat log, profile, Coach chat, saved meals, API keys, widget snapshot) but never touches Apple Health or Health Connect. Samples you've synced are yours; if you want them cleaned up, do it from Health / Health Connect settings. See Privacy Policy.