11 Differences Between Swimming and Gym Workouts That Impact Weight Loss

3. Muscle building and body composition: gym strength vs water resistance

Weight loss is not only about the scale. Body composition—how much fat versus muscle you keep—shapes long-term results and metabolism. Gym workouts readily offer progressive resistance training: you increase loads over time to build muscle and change body composition, which raises resting energy needs. Medical News Today highlights that resistance training increases muscle size and density, which supports lasting fat loss by boosting resting metabolic rate.