If a person's maintenance (energy in = energy out) is estimated at 2400 kcal/day, what daily intake should they target to lose approximately 1 lb per week, and what is the calculation rationale?

• A. About 1400 kcal/day, because losing 1 lb per week always requires halving daily intake relative to maintenance to create large deficits quickly for efficient weight loss.
• B. About 1900 kcal/day, because a 500 kcal/day deficit × 7 days = 3500 kcal (≈ 1 lb of fat).
• C. Maintenance should be reduced to 2400 kcal on weekdays and increased on weekends to offset metabolic adaptation, resulting in an average of 2100 kcal/day over the week.
• D. About 2000 kcal/day, using a rounded estimate that most people require a 400 kcal/day deficit to lose 1 lb weekly when accounting for spontaneous activity reductions.

Answer: (B)