Very few people get really drunk on weddings, even thought you can easily drink over half a litre of wódka throught the whole night.

I think that's because people eat fat stuff and soups with oil all the time (it stops alcohol from being absorbed quickly. It's important to eat the first fat meal before drinking), and they dance often (so the metabolism is faster).

EDIT: but yeah, in Russia they drink even more. Also the social protocols around drinking differs a little (tall glasses vs shot glasses for example).