What is one limitation of solely relying on weight as a measure of success in body composition?

Relying solely on weight as a measure of success in body composition can be limiting because it does not take into account changes in muscle mass. Weight can fluctuate for various reasons, including fluctuations in body water and fat levels, but it does not reveal the composition of that weight—how much of it is muscle versus fat. During a fitness program, a person might lose fat while gaining muscle, which can result in little to no change on the scale despite significant improvements in body composition. Therefore, measuring body composition directly and observing changes in muscle mass and fat percentage provides a clearer understanding of an individual’s progress toward fitness goals.