However the small intestine is by far the most efficient region of the gastrointestinal tract for alcohol absorption because of its very large surface area. Because of this, peak blood alcohol concentrations are achieved in fasting people within 0.5 to 2.0 hours, while non-fasting people exhibit peak alcohol concentrations within 1.0 to as much as 6.0 hours. Absorbed alcohol is rapidly carried throughout the body in the blood and once absorption of alcohol is complete an equilibrium occurs such that blood at all points in the system contains approximately the same concentration of alcohol. The remainder of the alcohol is eliminated through excretion of alcohol in breath, urine, sweat, feces and saliva. The body uses several different metabolic pathways in its oxidation of alcohol to acetaldehyde to acetic acid to carbon dioxide and water.
Healthy people metabolize alcohol at a fairly consistent rate.
Several factors influence this rate. The rate of elimination tends to be higher when the blood alcohol concentration in the body is very high or very low. Finally, the body's ability to metabolize alcohol quickly tends to diminish with age. In general, the less you weigh the more you will be affected by a given amount of alcohol. As detailed above, alcohol has a high affinity for water.