Which hormone helps regulate energy balance by inhibiting hunger?

• A. Ghrelin
• B. Leptin
• C. Insulin
• D. Peptide YY

Answer: (B)

Leptin communicates the body's fat stores to the brain, helping regulate energy balance by inhibiting hunger. Fat cells release leptin in proportion to stored fat, and when levels are sufficient, the hypothalamus reduces appetite and can increase energy expenditure. This makes leptin the primary long-term signal that tells the brain there is enough energy, supporting weight maintenance over time. In contrast, ghrelin from the stomach rises to stimulate hunger, peptide YY is released after meals to promote short-term satiety, and insulin can influence appetite but more as a response to blood glucose rather than the main long-term hunger regulator.