Which concept suggests that body weight is regulated around a genetically determined set point?

• A. Ghrelin
• B. Homeostasis
• C. Set point theory
• D. Anorexia nervosa

Answer: (C)

Set point theory says body weight is regulated around a genetically determined baseline. The brain, especially the hypothalamus, tracks energy stores in the body and uses signals from fat tissue and hormones like leptin to adjust hunger and energy use. When fat stores are high, these signals tend to reduce appetite and increase expenditure, nudging weight back toward the baseline. When stores are low, hunger rises and energy use can drop, pulling weight back up toward that set point. This framework helps explain why people often return to their usual weight after dieting or why small, ongoing changes in intake or activity produce limited long-term shifts. The other terms describe related but different ideas: ghrelin is a hormone that boosts short-term hunger, homeostasis is a broad principle of maintaining balance, and anorexia nervosa is a disorder, not a regulatory mechanism for weight.