You have never seen an alcoholic chug liquor like its water I take it? Long term alcoholics, talking decades+ here not youthful overindulgence, become incredibly tolerant and can consume huge amounts in ways that would make a normal person wretch. These are people who have altered their body chemistry enough that withdrawal is deadly.
"Long term alcoholics, talking decades+ <...> become incredibly tolerant and can consume huge amounts in ways that would make a normal person wretch."
That I can attest to. Only two weeks ago a longtime friend of mine died of cirrhosis of the liver and it was doubly horrible as it was very difficult to visit him in hospital due to COVID restrictions (although he wasn't infected as such).
The amount of alcohol he could put away horrified me. I'd often see him at functions and if I poured him a drink and I didn't fill his glass to the brim then he'd get irritated. The amount of alcohol he could consume and still remain coherent staggered me (if I'd consumed the same amount in a single sitting as he was able to then I'd be fully out to it under the table).
Sad really, he was trained as an organic chemist and he knew full well that his liver was being destroyed as it struggled in its first-pass attempt to eliminate the alcohol (that being the partial oxidation of ethanol into poisonous acetaldehyde).
In the mid 90s, I worked for a grocery store doing full time, overnight stock to partially pay for college. One of my co-workers for a period of time, whose name I now forget, was a barely-functional alcoholic. He would show up to work on time most days, and work through his shift. At lunchtime he would disappear for a period of time and he would come back smelling like Listerine.
Because that was his lunch.
A bottle of Listerine.
During the holidays they shifted some of us to a morning shift to continue to put items on shelves to match the holiday demand, and I saw him walk in on his day off, grab a fifth of bourbon and a fifth of vodka in the cheap plastic bottles, walk out, and walk back in about an hour later because he had consumed both bottles in his truck in the parking lot. He wanted a couple more to bring back to his apartment.
And as bad as his drinking was, the reason he had sole custody of his daughter is because his ex-girlfriend was a full blown drug addict and he was good at hiding his drinking from CPS.
My understanding is that serious alcoholics are drunks for days at a time. They go to bed with enough alcohol in their system to be drunk when they wake up, and they keep drinking throughout the day. Having zero alcohol in their system can be life threatening.
That means they can build up to whatever BAC slowly.
That seems low for "the most hardcore" alcoholics. If we exclude the absolute extreme top 1%, I'd wager the 95th percentile of alcoholics begins at 2 fifths (1.5L) of 40% liquor per day. And I might even be underestimating here.
