Final answer:
Leptin plays a vital role in hunger, eating, and satiety by regulating long-term balance between food intake and energy expenditure.
Step-by-step explanation:
Leptin plays an important role in hunger, eating, and satiety. It is a hormone released by fat cells that regulates long-term balance between food intake and energy expenditure. When there is more adipose tissue, more leptin is released, which decreases hunger and gives a feeling of fullness.