Nutrition is essential to maintaining a healthy lifestyle, yet many individuals lack awareness and control over their daily intake, increasing the risk of chronic diseases. This article introduces NutriMatrix, an Android-based application designed to help users independently manage their nutrition. The app enables users to log their daily food consumption, automatically calculate nutrient values, and receive AI-generated dietary suggestions. It also offers personalized progress reports over selectable timeframes (daily, weekly, or monthly). Developed using the Mobile Application Development Life Cycle (MADLC) method, NutriMatrix follows seven structured phases: identification, design, development, prototyping, testing, deployment, and maintenance. Key features include CRUD-based food logging, a nutrition calculator, an AI assistant called NutriBot for feedback and suggestions, and a progress report for tracking nutrient trends. The app also includes educational articles to promote healthy lifestyle. The backend was developed using Express.js and MySQL, while the frontend used React Native for cross-platform compatibility. Integration testing confirmed that all modules functioned smoothly and cohesively. The application was tested by 158 respondents using usability and user acceptance testing methods, resulting in an average usability score of 3.4 (85%) and a user acceptance score of 3.32 (83%), indicating a high level of user satisfaction and successful feature performance.