AI Nutritional Health Assistant: An Intelligent Personalized Nutrition Guidance System Built for Indian Diets

The open-source project AI Nutritional Health Assistant introduced in this article is an intelligent nutrition assistant designed specifically for Indian diets. It uses the FastAPI+Next.js architecture, combines LangGraph workflow orchestration and hybrid retrieval RAG technology (BM25+FAISS+Cross-Encoder), achieves a 90% recommendation accuracy rate, and supports calculation of over 25 health indicators and personalized recommendations for multi-regional Indian cuisines. The project aims to address the nutritional management challenges brought by India's dietary diversity and provide scientific, personalized dietary advice.

India has a rich and diverse dietary culture, from the creamy curries of North India to the fermented rice cakes of South India, each region has unique cooking traditions and nutritional structures. This diversity poses challenges for nutritional management—how to provide scientific, personalized nutritional advice while respecting regional dietary habits? The AI Nutritional Health Assistant was born to solve this problem.

Technical Selection

The backend uses FastAPI to build asynchronous APIs, the frontend uses Next.js 16+TypeScript, the data layer uses PostgreSQL to store user information, and FAISS implements semantic retrieval; the LLM selects the google/gemma-3-27b-it model from the NVIDIA NIM API.

Hybrid Retrieval RAG Design

Two-stage architecture: In the first stage, BM25 sparse retrieval and FAISS dense vector retrieval each recall 20 results; in the second stage, RRF fusion sorting is used, and Cross-Encoder re-ranks to select 5 results, which increases the recommendation accuracy to 90%.

Agentic Tool Calling and LangGraph Workflow

The Agentic mechanism allows the LLM to independently decide whether to query the database; the LangGraph state machine implements intent classification (meal planning/nutrition query, etc.), parallel processing (user profile retrieval + health indicator calculation), and conversation memory management.

Over 25 Health Indicators Calculation

Covers basic indicators (BMI/BMR/body fat percentage), derived indicators (TDEE/lean body mass, etc.), and nutritional indicators (macronutrients/micronutrients), using the Mifflin-St Jeor equation to ensure accurate metabolic calculations.

Regional Diet Support

Covers four major cuisines of North/South/East/West India. Food data comes from USDA, Indian food composition tables, and regional studies, supporting multi-language translation and refined preference configuration (vegetarian type/spiciness/allergies, etc.).

Deployment and User Experience

One-click deployment with Docker (docker-compose up --build), the frontend interface is simple and smooth. Practical scenario example: When a user asks for a 500-calorie South Indian lunch, the system recommends based on the user's health profile and analyzes the nutrition.

The project demonstrates good software engineering practices (modular design, type annotations, complete documentation) and provides a reference for vertical AI applications: combining general AI technologies (LLM/RAG/Agent) with domain-specific knowledge. Current limitations include dependency on data source quality, insufficient coverage of niche cuisines, and occasional inaccuracies of the LLM. The project is open-source and provides a solid solution for digital nutritional management of Indian diets.

The project welcomes community contributions: supplementing more regional cuisine data, improving nutrition algorithms, and optimizing the user interface. These directions will help the project address existing limitations, enhance feature coverage and accuracy, and better serve the needs of Indian dietary nutrition management.