Originally Posted by rrross
I am also trying to gain lean mass, while shedding some extra fat. I therefore can't set a weight goal myself either!
I have gained about 25 lb over the last year or so and I would say that you would find it very difficult if not imbossible to gain that much weight by using p90x. What you need to do (along with a good diet) is get into some powerlifting and bodybuilding exercises that will increase your free testosterone and mass), having said that, p90x is an OK place to start at for the first month or two into your building program.
As 01gt4.6 says, you will need to eat well. Being a skinny guy means you will need to put in a lot more calories than you are used to.
As far as protein goes, it is standard to take in at least 1gram protein per lb of body weight each day.
Brad, i'm in the same predicament. I'm 6-2, 160 and trying to put on muscle mass as well. I used P90X for a while, but realized its more for ppl who are wanting to shred fat and looked ripped. I've read that if you want bulk, you can use P90X for base fitness for a few weeks (skip the cardio stuff), but you'll eventually need to hit the gym and the heavy weights. Compound exercises on the large muscle groups works best, using heavy weight.
Also important, like the others said, is to eat right. Use the Harris-Benedict equation to calculate your BMR (how many calories you need to eat to maintain your current weight.) Then multiply that total by 1.55 to signify moderate exercise (about 3 times a week in the gym), then take that total and add 500 to it in order to (hopefully) gain about a pound a week. This grand total is the number of calories you should consume per day if you wanna gain weight. It should be broken down into about 20% protein, or more if you want, 30% fat (as much good fat as possible, ex. monounsaturated), and the other 50% carbs. Thats where this website comes into play for me, i only use it as a calorie tracker.
Hope this helps, good luck!