<![CDATA[Water is a vital element for sustaining human physiological functions, ranging from metabolic processes to cognitive and physical performance. Insufficient daily water intake can trigger various health problems that significantly reduce individual well being. Machine learning provides a data driven approach to classify hydration levels more objectively based on individual and environmental attributes. This study evaluates and compares the performance of three classification algorithms Random Forest, Naive Bayes, and K-Nearest Neighbor in predicting hydration status (Good or Poor) using the Daily Water Intake public dataset comprising 30,000 samples. Class imbalance in the dataset (79.7% Good, 20.3% Poor) was addressed through SMOTE, while Stratified K-Fold Cross Validation with K=10 was employed for model evaluation. Hyperparameter optimization was performed using Grid Search, and model performance was assessed through accuracy, precision, recall, F1-Score, and AUC-ROC metrics. Results demonstrate that Random Forest achieved the highest accuracy of 99.50% and AUC-ROC of 0.9999 after optimization thanks to its ensemble mechanism, which captures non-linear relationships among features, outperforming Naive Bayes, which is constrained by its feature-independence assumption. KNN showed the most notable improvement post optimization with an accuracy gain of 0.62% (from 97.62% to 98.24%), while Naive Bayes remained unchanged at 83.53% as its optimal parameter matched the default value. These findings offer evidence based guidance for algorithm selection in hydration classification systems.]]>
