Which mechanistic explanation best analyzes how set point theory and physiological adaptations after weight loss contribute to weight regain?

• A. Physiological adaptations after weight loss exclusively improve insulin sensitivity and therefore lead to spontaneous long-term weight maintenance without behavioral support.
• B. Set point theory states that only psychological factors cause regain; physiological energy expenditure and appetite hormones remain unchanged after weight loss.
• C. After weight loss, resting energy expenditure often decreases and appetite-regulating hormones (e.g., ghrelin) may increase, creating stronger physiological drives to eat while burning fewer calories—consistent with set point adaptations favoring regain.
• D. After weight loss, the body always increases basal metabolic rate and permanently suppresses appetite, which directly prevents any meaningful risk of weight regain.

Answer: (C)