Interventions based on information technology (IT), particularly mobile health (mHealth), have significant potential in nutrition research. This study aimed to design, develop and assess the usability of a smartphone application for dietary data collection and monitoring. The study utilised design and development research to evaluate FoodLog, a smartphone application (app) for dietary data collection, through a pilot survey involving 101 young working adults aged 25-45 in Pune, India. Data was gathered using an online mHealth App Usability Questionnaire (MAUQ) created in Google Forms, and statistical analysis, including t-tests and mean calculations, was conducted. The literature search informed the development of key features such as text-based logging, food recognition, nutrient analysis, BMI monitoring, dietary habits, FAFH consumption, water intake and food expenditure. The pilot study assessed the usability of the FoodLog application, yielding an average MAUQ score of 2.67 out of 7, which is considered acceptable. There were no significant differences in usability opinions across sub-scales. This study's results contribute significantly to the advancement of more efficient and user-friendly methods for dietary assessment. The study evaluated FoodLog within real-world contexts, thereby enhancing its practical relevance and external validity in comparison to controlled laboratory environments.