The body can't use more than 30g of protein at a time (I forget how long the period is)
There are 8 pints in a us gallon and 15mg of protein in a pint so that's 120 grammes or protein a day, not to mention aprox 120g of fat per gallon of whole milk.
You'll need to be lifting heavy, often and doing regular cardio also.
Most trainers also reccomend doing 3x10 for at least three months or more to get your joints and tendons used to lifting, I believe.
5x5 is good for strength but 3x10 full body two or three times a week is still better for hypertrophy (mass.)
For
muscle synthesis, 20-30 g of protein seems to be the most the body can utilize. However, eating more than 20-30 g per meal isn't necessarily a bad thing:
http://www.precisionnutrition.com/protein-limit
@ OP: By powerlifting, do you mean people who do squats, bench, overhead, deads when they lift, or people who lift extremely heavy? My stats aren't anything impressive, but doing the 5x5, I rarely see anyone lift as much as me. I know some of the people at the gym look like they could be lifting as much or a lot more than me, but it seems like they'd rather not. Don't know if it's because they don't want to look bad if they fail to do a lift, or because they'd rather work on their biceps and abs.
Powerlifting is about increasing your strength at squatting, benching, and deadlifting. So, yes, you'd be lifting heavy weights at low repetitions.
From what I've seen, Koreans don't lift using weights where they can only do a few reps (i.e., one to five). They typically do AT LEAST 8 reps as they focus on hypertrophy and/or think low reps are outright dangerous (a somewhat common misconception).
But, not everyone's the same, so some people actually get a bigger hypertrophy response doing lower reps. Also, you really can't go wrong focusing on strength for hypertrophy--you'll see the results eventually. For example, a guy who benches 250 lbs will almost always have a bigger, more muscular chest than a guy who benches 150 lbs.
Anyway, if hypertrophy is your goal, try 8-12 reps first and see. After 6 six weeks, try switching to low reps. Weight lifting is largely trial and error in my opinion since not everyone responds identically when doing X program/workout.
To me, strength is the main focus and muscle is just a byproduct. I do care about being in shape, of course, so I also watch my diet.
