Lifting weights significantly affects body composition by increasing muscle mass and reducing body fat. Resistance training stimulates muscle hypertrophy, leading to greater lean body mass, which enhances the body's metabolic rate. Increased muscle mass requires more energy for maintenance, thereby promoting fat loss during both exercise and rest. Furthermore, weightlifting can improve body strength, functionality, and overall posture. Consistent weight training also contributes to improved insulin sensitivity and metabolic health, making it a vital component of a well-rounded fitness regimen aimed at enhancing body composition.