A local gym offers a 'detox' program that combines 3 intense fitness classes daily with restricted eating to 900 kcal/day for two weeks. Synthesize course concepts to determine the most likely long-term outcome for participants and provide a justification.

• A. Likely quick short-term weight loss followed by regain because extreme restriction and unsustainably high exercise volumes often cause loss of lean mass and are not maintainable; sustainable moderate deficits with progressive exercise are preferable to reduce disease risk long term.
• B. Participants will experience improved immune function and bone density because short-term low calorie diets enhance physiological resilience.
• C. The program is optimal for all ages and health statuses and requires no medical oversight because short-term intensive strategies are universally safe and effective.
• D. Guaranteed sustained weight loss and improved metabolic health because combining high exercise volume with calorie restriction always produces permanent changes in body composition.

Answer: (A)