Standardized sizes and pattern grading practices used in the industry contribute to poor fit. Sizing systems are based on anthropometric data and in turn grading systems are based on sizing systems. Grading practices are based on assumptions that all body measurements increase and decrease in both width and length at the same rate and location when migrating from one standardized size to another. This funded longitudinal study was initiated to examine how various body shapes transform as they migrate through multiple standardized apparel sizes and explore the relationship of body shape to current fit and grading practices. Men and women over the age of 18 enrolled in weight loss programs are receiving 3D body scans with each 10 pounds of weight loss to examine body shape and size changes. Preliminary data and study methodology are presented.