Final answer:
Protein is the most satiating of the energy-yielding nutrients due to its effects on satiety hormones, slower digestion, and higher energy cost of metabolism.
Step-by-step explanation:
The energy-yielding nutrient that is most satiating is protein. Unlike carbohydrates and fats, which are the body's primary energy sources providing 4 and 9 calories per gram respectively, proteins offer both a source of energy and the essential amino acids necessary for building and repairing body tissues. Protein-rich foods tend to be more filling because they can significantly affect satiety hormones and slow digestion, leading to a longer sensation of fullness. Additionally, the metabolic processing of protein is more energy-demanding compared to carbohydrates, which may further contribute to its satiating effect.