Lads (and lasses), this is where you have to sit down and have a talk with yourselves.
1% of guys and girls out there are so genetically gifted that it doesn't matter what they eat/how they train, they'll always look like a million dollars and us mere mortals will never get that close.. those lucky few will also make a career out of their physiques and be made for life. So good for them!
Now, for the rest of us, we have to work bloody hard for our bodies to even budge. The human body is a cowardly, lazy piece of sh!t which would like to be 150lbs with a nice 20% bodyfat, a lifestyle with little or no heavy lifting and a lot of comforting food.
It does NOT want to be 250lbs at 8% bodyfat (just an example), getting 400-500g of protein in daily and grinding out 350lb widowmaker squat sets every week. What we're trying to do, with varying degrees of ease and success (thanks to our individual genetics) is go against our bodies wishes and it's a battle, it's a real fvcking battle.
The eating is a battle, the training is a battle, getting enough sleep and rest is a battle, and it's not easy. But if we want to enjoy a damn good physique in our young and adult lives then we've got to fight for it, because unless we're gifted that way, we're doing the exact opposite of what we physiologically want to do. If in our 30s and 40s we want to look great, devoid of beer bellies, low test levels and whatever else comes with that age, we've got to work now. Here and now, first in our late teens, then into our 20s and finally into our 30s when we're just icing the cake, putting that final swell and polish on our biceps/abs/quads/whatever. In my opinion it takes 3-5 years of hard work, trial and error, setback and injury (hopefully not), blood sweat and tears, to actually put our bodies into a shape that we'd be satisfied with, some people stop there, but others (like myself) want to constantly improve and keep on growing/slimming/whatever and won't stop until really, our bodies can't (not won't, CAN'T) cope with the intensity anymore.
Now, it's not an easy decision to make, to become a serious bodybuilder (I'm not talking a 250lb pro here, I'm talking about someone who takes nutrition and training seriously and makes it part of their lifestyle rather than the 160lb bicep boy/beach muscle d!ckhead who does 50 sets of bicep curls (in the freakin' squat rack to look even more hardcore), doubtlessly with his delts and lower back doing most of the work, and then whips his shirt off to admire the pump on his colossal 14 inch guns).
But once you've taken this decision, you've got to make sacrifices. Not getting trashed is one of them. Once in a while will do no harm (but you can effectively scratch the next coupla days' sleep and nutrition plan and don't even think about working out at peak efficiency) but do this on a regular basis and you'll gain absolutely nothing. (I'm talking about getting so drunk you're hungover as hell and looking like something out of Resident Evil the next day, NOT by having a couple of drinks at the weekend with your friends)
It takes discipline, yeah, and I know what society's like today, everything seems to rotate around the next time you wake up in a faceful of your own vomit in some gutter, or naked next to someone you don't know the name of.. well, you've got to give up most of that. I'm not saying don't drink (I'm a real ale man myself for you UK bods but in strict moderation) or don't have a lovelife (perish the thought!!) but getting drunk and then going out the next day and attempting a widowmaker is recipe for disaster. You just won't get it done.
When I was in college I got drunk one night, threw up, felt terrible, and that was it. No more. Did I not enjoy life afterwards? Of course I did! I enjoyed life to what I considered the full, and still made great gains with my physique, and now have a body I can think proudly of and say "I did this, I wasn't born this way, I got here by myself and it took sacrifices but I made it".
Every time you get trashed so that you can't eat, rest or workout properly you're pushing yourself even further away from that goal, to reach that day when you can actually put down the dumbbells, tear up the logbook (or bury it somewhere for posterity, hell I even give mine funerals) and say "I did it, I got here."
Now if you want to get smashed on a regular basis (while in your teens, at college, whatever) I'd recommend giving up training altogether. Save the money you'd spend on a gym membership, protein and other supplements, food, equipment etc and live however you want, but DON'T even try to get any gains because there's no point, you won't have any.
Okay, there's guys who can get drunk every night and still look absolutely fantastic. I had a friend like that at college, he was bigger and stronger than me, got smashed off his face every night, ate once a day (100g of protein max, one solid meal and one shake preworkout), did 30 mins of hard cardio and an hour of weights every single day (no rest days and no set workout plan, just whatever he fancied doing) and yes, he still looked better than I did. But if you're that sort of person you probably know by now.
And yeah, maybe you do gain a little muscle even while getting hammered all the time. But stop the weights and it'll go, and the only thing growing on you will be that beer belly.
Seriously, if you want to get raving drunk and eat junk all the time go ahead, but don't waste your time trying to workout productively at the same time.
And as for alcohol as a source of calories, don't even get me started..