Everyone knows you’re supposed to eat something “to line the stomach” before you hit the town, but why is that?
Alcohol is pretty volatile, around 5% of what you drink is expelled through the lungs. It’s why you can smell alcohol on someone’s breath, and it’s how breath testers work. Breathalysers just take advantage of the fact that there is a constant ratio of 1:2300 between the amount of alcohol exhaled and blood alcohol level.
The rest of the alcohol is broken down in a three step process.
1. Alcohol dehydrogenase converts alcohol to acetadehyde with the help of coenzyme NAD. This is the rate-limiting step in the metabolism of alcohol, and the reason you can only metabolise about one standard drink an hour.
2. Aldehyde dehydrogenase converts the aldehyde to acetic acid (vinegar.)
3. Acetic acid is broken down into carbon dioxide and water, releasing energy. This energy, along with the molecules of NADH that are produced along the way, is the reason alcohol is high in calories.
This be a rare example of zero-order metabolism, meaning that it doesn’t get faster when there’s more alcohol. It’s probably due to the small amount of enzyme (or the coenzyme) in that first step becoming saturated after only a small amount of alcohol.
So why do they say you shouldn’t drink on an empty stomach? It all comes back to that nifty enzyme, alcohol dehydrogenase. 85% of the metabolism happens in the liver (that be why liver disease is common ‘mongst alcoholics) and 15% happens in the stomach where the enzyme is present in the lining. It breaks down the alcohol before it can even enter your bloodstream!
Drinking anything on an empty stomach causes rapid gastric emptying, reducing the time the alcohol is exposed to the alcohol dehydrogenase in your stomach lining. Rapid emptying means that the alcohol hits your bloodstream faster and in greater concentration, resulting in a state of inebriation that is more ass than class.
Women have about 50% less gastric alcohol dehydrogenase than men, one of three reasons that women have higher blood alcohol levels than men after the same number of drinks. The other two being that men have more muscle, which has lots of blood vessels giving the alcohol more space to dilute in, and women have more body fat, which does not soak up alcohol and therefore concentrates it in the blood.
So ’tis true indeed that you should eat well before a night of drinking. I myself have conducted extensive experiments on this matter (in the name of science), and never have I been drunker than at my pirate-themed 21st, which I attribute to my skipping dinner that night. Although the two for one cocktail hour probably didn’t help.