An athlete aged 30 has a measured BMR of 1,900 kcal/day. Over a training season they increase activity energy from 600 to 1,200 kcal/day and TEF is estimated at 12% of TEE. Recalculate TEE at baseline (activity 600) and peak (activity 1,200), solving iteratively if TEF depends on TEE.

• A. Baseline ≈ 2,500 kcal/day and Peak ≈ 3,100 kcal/day, ignoring TEF dependence on TEE.
• B. Both baseline and peak TEE remain 1,900 kcal/day because BMR is the only determinant of TEE in trained athletes.
• C. Baseline ≈ 2,841 kcal/day (TEF ≈ 341 kcal); Peak ≈ 3,523 kcal/day (TEF ≈ 423 kcal).
• D. Baseline ≈ 2,400 kcal/day and Peak ≈ 3,000 kcal/day assuming TEF = 10% fixed rather than 12%.

Answer: (C)