This document proposes a food recognition system using smartphone cameras to estimate calorie and nutrient values from photos of food. It involves image segmentation, feature extraction, and classification using a decision tree approach. Specifically, the system takes photos of food before and after eating, segments the images to identify the food type and portion size, then uses nutrient databases and the decision tree to estimate calorie content. The goal is to help with obesity treatment by automatically monitoring patients' daily food intake and calories through analysis of food photos. Key steps include pre-processing images, segmenting into regions, measuring food portions, and classifying calories using decision tree algorithms and nutrient fact tables.