I see some misinformation being spread in here...
First of all, Do not have one gram of protein per lb of body weight. You will be ingesting too much protein than your body can use and the excess will be handled by the kidneys and excreted through the urine. Not only is this a waste of money and will make you have to pee more, it also makes the kidneys work harder than necessary and can lead to health problems down the road.
Another important thing to consider is that protein does have a dehydrating effect on the body. Drinking a protein shake right before a workout or during a workout will suck needed water from your body. If you know anything about working out, you'll know that hydration is necessary for maximum muscle efficiency. Maximum muscle efficiency is needed for maximum muscle performance, which is needed for maximum muscle gain and other strength enhancement.
Somebody said that maximum weight loss is best achieved by working out the whole body. Yes, this is true, but it should be explained a little more in depth.
A. You do not need to work every muscle during the same day. Due to fatigue and rest, it is more effective to split up your workouts. Even so, working out all muscle groups should never be an issue.. whether you're weight training for weight loss or not. ALWAYS WORK YOUR ENTIRE BODY.
So many people think they look good when they just work out their biceps, or just work out their upper body. Obviously this is in the eye of the beholder (but I think toothpick legs look retarded.) Either way, it's unhealthy. Working out only your upper body does not allow for muscular support in the joints of the lower body (knees, ankles, hips) which leads to increased strain on these joints.. and will eventually lead to joint problems. How about those guys you see who look like they're constantly carrying around beach balls because "Their arms are so big." This has nothing to do with their arms being so big, it's usually an imbalance of musculature between the biceps and triceps and leads to a reduced range of motion in the arms.
Always keep this in mind - there are many ways to get big and strong. People can get large by using unhealthy methods (steroids anyone?) People can also get big even though they are using inefficient methods, it'll just take them longer. It'll be more difficult and require more work.