A common phrase that you may have heard thrown around the industry is "protein is muscle" or "muscle is protein". Whilst muscle is comprised of protein - an increase in dietary protein may not necessarily result in more lean muscle mass gains.
Touching on the "muscle is protein", this somewhat deceiving phrase has come as a result of the structure of a muscle cell. Muscles are your body's primary storage facility of amino acids (amino acids are the building blocks of protein). If your body requires protein, and there is not enough dietary protein being consumed, then muscle tissue will most likely be broken down in order to supply the required amino acids.
Obviously, if muscle is comprised of a significant amount of amino acids, then you need to source these amino acids from somewhere. This comes from your diet.
That said, more protein in your diet does not necessarily mean great lean muscle gains. Gaining muscle is a function of many variables, including:
Resistance training regime
Cardiovascular exercise regime
...and many other factors
Let's take a few examples. To begin with, Fred's diet is spot on. He is consuming an adequate amount of carbohydrate, protein and fat. However his resistance training regime is not conductive of gaining muscle. Instead of stimulating the muscles to grow, he is performing a high-repetition workout which will enhance his muscular endurance. Therefore he will not see significant muscle gains.
Example 2 - John performs an effective resistance training routine. However his diet is lacking in carbohydrates. Carbohydrates are required in the process of "protein synthesis" - ie. building muscle. Without carbohydrates, protein synthesis will cease to occur (as protein synthesis requires the presence of insulin). Instead, muscle will most likely be broken down into amino acids which are then converted into glucose in order to maintain blood glucose levels.
Example 3 - Jack sleeps 2-3 hours each night. Whilst his diet and training routine may be spot on, the lack of sleep that he receives inhibits his ability to synthesise protein. His hormones are imbalanced because IGF-1 and HGH, two important hormones for building muscle, are secreted in high amounts during deep sleep.
Whilst I could go on all day with various examples, the point is that build muscle is a function of many variables. You need to ensure that your protein intake is adequate in conjunction with all other considerations. Consuming protein shakes all day long will not necessarily enhance your results in the gym. One other very important factor is to ensure that you have a calorie surplus in your diet - ie. more calories being consumed than what is being expended.
When you enhance all these factors, your overall progress will be significantly enhanced.
With that in mind, several studies have suggested that 1.8-2.4 g/kg/day of protein is adequate for maximum results. So, for a 100kg person, 180-240g of protein is substantial. There is limited research on this topic however. I would suggest that you begin within this range. Down the track, once you learn how your body responds to your training and diet, it's a great idea to experiment with different nutritional and training strategies. Unfortunately there is no formula, simply because we are all very different in our genetics.
I highly suggest that you have a read of a course that I am publishing which deals with this very topic. There is particular emphasis on nutrition and the importance of protein, fat and carbohydrate:
Hope this is of help!