Food Diary

AI-powered mobile food diary — photograph a meal to identify it, or search ingredients manually. Built with React Native, FastAPI, and the LogMeal food recognition API.

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What it does

Food Diary lets users track daily calorie intake through two logging flows:

• Photo log — take a photo or pick one from the gallery. The image is sent to the LogMeal segmentation API, which returns bounding boxes and top-5 dish candidates for each detected food region. Users confirm (or correct) each region, edit the serving size in grams, and kcal updates instantly without an extra API call.
• Manual log — search a locally cached ingredient catalogue (≈3 000 items), add ingredients to a basket, set grams per item, and compute total kcal in one call.

All entries are stored in a date-grouped diary with per-day kcal totals, photo thumbnails, and swipe-to-delete. An optional profile screen tracks weight, height, goal, and dietary preference, with live BMI calculation.

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Architecture

Android App  (Expo / React Native + TypeScript)
      │
      │  HTTPS + Bearer JWT
      ▼
FastAPI  (Railway)  ─────────────────────────────┐
  ├── /auth       →  Supabase Auth               │
  ├── /profile    →  Supabase Postgres            │
  ├── /diary      →  Supabase Postgres            │
  └── /logmeal/*  →  LogMeal API  (key server-side only)
                                                  │
                     Supabase Storage  ◄──────────┘
                     (meal-images bucket — public URL
                      stored in diary_entries.image_url)

The mobile app never calls LogMeal directly. The LOGMEAL_API_KEY lives only in Railway environment variables and is never shipped in the APK.

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Stack

Layer	Technology
Mobile	React Native, Expo SDK 54, TypeScript (strict)
State	Zustand — one store per domain
Backend	Python 3.12, FastAPI 0.115, httpx async
Database	Supabase Postgres (profiles, diary entries, ingredient cache)
Auth	Supabase Auth — JWT, OTP email verification, auto-refresh
Storage	Supabase Storage — meal-images bucket
AI	LogMeal API — food segmentation, confirmation, nutrition
Deployment	Railway (backend), EAS Build (Android APK)

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Getting started

Run the one-shot setup script to wire git hooks, create the Python virtualenv, install mobile dependencies, and validate project files:

bash setup.sh

Or set up each part manually:

Prerequisites

Tool	Version
Python	3.12
Node.js	≥ 20
EAS CLI	latest — npm install -g eas-cli

Backend

cd backend
python3 -m venv .venv && source .venv/bin/activate   # Windows: .venv\Scripts\activate
pip install -r requirements.txt
cp .env.example .env          # fill in the three variables below
uvicorn app.main:app --reload

requirements.lock is the pinned lockfile generated from requirements.txt. The Dockerfile uses the lockfile for reproducible builds. To update dependencies: pip-compile requirements.txt -o requirements.lock

Confirm it is running:

curl http://127.0.0.1:8000/health
# {"status":"ok"}

Mobile

cd mobile
npm install

Create mobile/.env:

EXPO_PUBLIC_API_URL=https://food-diary-production-cd15.up.railway.app

Start the dev server and press a to open on an Android device or emulator:

npx expo start

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Environment variables

backend/.env

Variable	Description
SUPABASE_URL	Supabase project URL
SUPABASE_SECRET_KEY	Service role key — backend only, never in mobile
LOGMEAL_API_KEY	LogMeal API bearer token — backend only, never in mobile

mobile/.env

Variable	Description
EXPO_PUBLIC_API_URL	FastAPI backend base URL
EXPO_PUBLIC_SUPABASE_URL	Supabase project URL (for client-side session refresh)
EXPO_PUBLIC_SUPABASE_ANON_KEY	Supabase anon key (public — safe in mobile)

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APK

Download APK

Requires Android 10 (API 29) or later. To install: go to Settings → Apps → Special app access → Install unknown apps, enable installation from your browser or file manager, open the APK, and tap Install.

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Demo

https://www.youtube.com/watch?v=bUg6UNzSWow

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Repository structure

food-diary/
├── backend/          FastAPI — auth, profile, diary, LogMeal proxy
│   ├── app/
│   │   ├── routers/  auth.py  profile.py  diary.py  logmeal.py
│   │   ├── models/   schemas.py
│   │   ├── middleware/auth_guard.py
│   │   └── db/       supabase.py
│   └── Dockerfile
├── mobile/           Expo React Native — Android app
│   └── src/
│       ├── screens/  PhotoLogScreen  ManualLogScreen  DiaryScreen  ProfileScreen
│       ├── components/BboxOverlay  Toast  Button  Input  PickerField
│       ├── store/    auth.ts  diary.ts
│       ├── api/      client.ts
│       └── theme/    colors  spacing  typography
├── docs/             Architecture and user manual
├── .github/          CI workflow and Copilot instructions
├── .githooks/        Pre-commit AI usage guardrail
├── .vscode/          Recommended extensions, workspace settings, and debug configs
└── setup.sh          One-shot dev environment bootstrap

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Docs

• Architecture — system diagram, API reference, caching and auth design
• User manual — step-by-step guide for all five flows
• Performance profiling — runtime analysis of POST /logmeal/segment
• Contributing — git workflow, commit conventions, and AI disclosure rules
• Changelog — release history in Keep a Changelog format
• AI usage disclosure — full record of AI-assisted and manual changes
• Known limitations — free-tier constraints and deliberate design choices