Blood alcohol content (BAC) is a measure of the amount of alcohol that is present the blood.
A heavier person will have a lower blood alcohol level due to a greater amount of water in their body. The more a person weigh, the more water he/she tends to have in his/her body. The water has a diluting effect on the alcohol so the BAC will be lower in comparison with person who is slimmer and has less water in the body.
