I've always wondered why in manga/manhwa the characters get drunk off like 1 can. Is beer ...

I actually think that a lot of people of Asian descent get drunk easier. in fact, there’s a lot of people there who are mildly allergic, which is why their face goes red

Asian people have low alcohol tolerance because they have deficiency in aldehyde dehydrogenase - an enzyme that breaks down the toxic aldehyde -a byproduct from breaking down of alcohol. The high aldehyde concentration in the blood is toxic, makes them get drunk much easier and therefore get "flush" syndrome.

idk what the other comments are saying, I'm East Asian, I don't get drunk with 1 can of beer and I've NEVER seen anyone get drunk with 1 can of beer either. Not to mention I don't usually drink and I'm quite small in build so my tolerance shouldnt be high supposedly.

Getting drunk is really just a plot device for characters to do stuff OOC, have sex, and/or conveniently forget things for drama LMAO

yes this person is right BUT this reaction doesn't necessarily mean "drunk" in the average sense strictly speaking. The symptoms usually just end up being the same as being "drunk" because you feel so lightheaded, nauseous and hot because of the reaction to the aldehyde. So unlike what another person above said (they said they don't usually drink so maybe they haven't seen it yet), there are asians who do get drunk from one drink, clearly they must fall in the percentage that don't. I've also seen very petite white friends who have eaten very little get drunk from one beer so it's not impossible at all.

But there are different levels of low tolerance in East Asians due to genetics. Typical Asian flush is very common but doesn't necessarily mean low tolerance as it may take a lot of alcohol to get flushed or the person might get flushed quickly but break down the alcohol afterwards hence not getting as drunk as quickly. These people may have a deficiency of enzyme but not completely lack it. There are also two genes responsible for this reaction so it's very complex. However, some Asians completely lack the enzyme that breaks down acetaldehyde such as my dad so he goes completely red and is drunk after only a few sips of red wine or half a beer and has to go lie down. Keep in mind he is 5'11 with a fairly muscular build so his tolerance shouldn't be that low but due to his race-related genetics, it is. I am half east asian (Chinese) and I still get flushed and will easily get drunk on one can of beer eg. Cass (Korean sized cus they pretty big lol) if I down it in 10-20mins without eating right beforehand (and I'm 5'9 and not skinny lmao). It really depends, which is why in webtoons there's always a bunch of characters who drink heaps and are fine and one of the characters who get drunk super quickly.

To put it in context, out of all my asian friends, probably half suffer from Asian flush and the other half are totally fine. I believe the proper statistic is 40% of east asians get it.

So no, Asian beers are average alcohol content (though they do come in big sizes) but it is certainly realistic for someone of east-asian heritage to be flushed and "drunk" after only one beer.