How does cortisol affect the body's metabolism?

Cortisol plays a crucial role in metabolism, primarily by promoting glucose availability and encouraging fat breakdown. Under stressful conditions, cortisol is released from the adrenal glands and functions to mobilize energy resources to support the body's immediate needs.

One of cortisol's primary effects is its stimulation of gluconeogenesis, the process by which the liver produces glucose from non-carbohydrate sources. This increases the availability of glucose in the bloodstream, ensuring that tissues, particularly the brain and muscles, have a sufficient energy source.

Additionally, cortisol facilitates the breakdown of fat stores (lipolysis), which also contributes to increasing free fatty acids in the circulation for energy use. This is essential during prolonged stress or fasting, where the body needs to efficiently utilize its energy reserves.

The fact that cortisol can also influence protein metabolism is essential, but its primary actions in the context of metabolism include enhancing glucose availability and promoting the breakdown of fats to provide the necessary energy during stress, making option B the most accurate choice.