An individual weighing 80.0 kg with 20.0% body fat undertakes a 12-week program: they lose 3.0 kg of fat mass and gain 2.0 kg of muscle mass (assume muscle mass increase fully increases body weight). Calculate the new body weight and new percent body fat. Show your work.

• A. New weight = 82.0 kg; new body fat ≈ 15.9%.
• B. New weight = 82.0 kg; new body fat = 10.0% because muscle gain reduces fat percentage proportionally by more than expected.
• C. New weight = 79.0 kg; new body fat = 16.5%, assuming fat loss and muscle gain cancel out differently and reduce scale weight.
• D. New weight = 80.0 kg; new body fat = 20.0% because body composition changes rarely affect percent fat in 12 weeks.

Answer: (A)