But WHO's standards (2-3 drinks/day) won't make you gain weight if you live a healthy life otherwise (if you didn't, you'll gain that weight anyway, so hard to say if that was the alcohol doing that; sure if you drink 10 pints/night yes, but 2 normal sized drinks...) and that shorter lifespan is doubtful, but that's anecdotal from my side (the statistics WHO uses are not very convincing though; they just note everyone who drinks and has ailments and when they run their matlab algo's over it, they attribute all these which are known to be affected by alcohol to alcohol (ab)use, at least in the ones I read).

Btw. I think the WHO recommends no more than 2(3 for men) drinks per day and no more than 6-7 per week, so that would account for the periods of heavy drinking. You cannot really drink heavy and stay below that.