Usability and Feasibility of PmEB: A Mobile Phone Application for Monitoring Real Time Caloric Balance

Obesity is a major public health challenge with over 65% of U.S. adults either overweight or obese. Estimated annual costs of obesity are around $78.5 billion. Self-monitoring is a critical skill for successful weight management. However, self-monitoring is labor-intensive and compliance is often difficult. In this paper, we describe the Patient-Centered Assessment and Counseling Mobile Energy Balance (PmEB) cell phone application that allows users to self-monitor caloric balance in real time. We developed and applied a four-phase iterative research and development methodology. We conducted a usability study and a preliminary feasibility study. The one month feasibility study measured compliance and satisfaction among a sample of 15 participants randomized to one of three groups: 1) a paper diary group, 2) a PmEB group with one daily prompt, and 3) a PmEB group with three daily prompts. PmEB scored highly on usability, compliance, and satisfaction. In addition, cell phone group users scored PmEB the same as or better than Paper Group members scored the paper diary in nearly all categories. Thematic analysis of comments revealed very positive reviews of PmEB as well as areas for improvement. PmEB is both usable and feasible for self-monitoring in weight management, and our iterative pilot study methodology was effective in improving its usability