A nurse is educating a group of patients about metabolic rate and its implications for nutritional needs. Which explanation accurately defines metabolic rate in a way that helps patients understand how their bodies use energy?

Metabolic rate refers exclusively to the calories burned during physical exercise and activity.

Metabolic rate is the energy used only when a person is asleep and not active.

Metabolic rate is the rate at which the body burns food energy to support all bodily functions, including involuntary activities like heartbeat and respiration.

Metabolic rate is the total amount of calories consumed during a 24-hour period.