Blood alcohol level is measured as the concentration of alcohol per unit of blood in the body. It is a good indication of how intoxicated a person is.
This can be measured by testing breathe, blood and even urine.
It is not a good system to measure how many drinks a person has had, since body weight, metabolism, health, etc. varies among different people, so testing the blood alcohol level is a good system to use.
Energy is another word for "calories." Your energy balance is the balance of calories consumed through eating and drinking compared to calories burned through physical activity. ... People who are more physically active burn more calories than those who are not as physically active.