Why would a woman of the same size as a man likely have a higher BAC?

The reason a woman of the same size as a man would likely have a higher Blood Alcohol Concentration (BAC) is due to physiological differences in body composition, specifically the higher percentage of body fat that women generally possess compared to men.

Alcohol is distributed in water rather than fat; therefore, a person with a higher body fat percentage will have a smaller volume of water in which to dilute the alcohol. Since women typically have a higher percentage of body fat and lower water content than men, when they consume the same amount of alcohol as men of the same size, the alcohol is less diluted. This leads to a higher concentration of alcohol in the bloodstream, resulting in a higher BAC.

While muscle mass can affect alcohol distribution, in this context, it is the significant difference in body fat percentage that plays the most critical role. Liver enzymes and alcohol metabolism rates can vary individually but are not consistent factors in the comparison of men and women. Additionally, the generalizations regarding consumption patterns do not necessarily influence the BAC directly but may reflect differences in drinking behavior rather than physiological outcomes.