Final answer:
Dinitrophenol (DNP) blocks ATP production by preventing the movement of protons through the ATP synthase, resulting in weight loss.
Step-by-step explanation:
Dinitrophenol (DNP) is an "uncoupler" that makes the inner mitochondrial membrane "leaky" to protons. It prevents the synthesis of ATP by blocking the movement of protons through the ATP synthase, halting ATP production. The stored energy then dissipates as heat, causing weight loss.