Which argument best analyzes why relying exclusively on exercise is often a poor standalone strategy for sustained weight loss?

• A. Because exercise burns zero calories unless combined with a specific supplement, so relying on exercise is physiologically impossible without pharmacologic augmentation.
• B. Because only high-intensity interval training (HIIT) works for fat loss, and all other exercise modalities are counterproductive without surgery.
• C. Because exercise always leads to weight gain due to increased muscle glycogen storage, making diet irrelevant.
• D. Because exercise can increase hunger and caloric intake, is time-consuming to match large caloric surpluses, and may be less sustainable than dietary changes, so combined diet and activity interventions are generally more effective.

Answer: (D)