Final answer:
Leptin is the hormone that suppresses appetite and promotes energy expenditure by signaling the brain to induce satiety and manage energy balance.
Step-by-step explanation:
The hormone that suppresses appetite and increases energy expenditure is Leptin. Leptin is a protein hormone secreted by adipose tissues and it plays a crucial role in regulating energy balance by inhibiting hunger, which in turn diminishes fat storage in adipocytes. Leptin is released after eating and signals the hypothalamus to suppress hunger, promoting a feeling of fullness and thereby controlling food intake. Dysregulation of leptin can lead to obesity, as it might not properly signal the brain to stop eating. This hormonal mechanism is an important consideration in the research of obesity treatments.