Quote (ForbiddenOath606 @ Jun 30 2014 01:22pm)
Partial truths from old studies.
The actuality is that everyone's protein requirements differ depending on the following:
1. Type of protein consumed
2. Presence and Concentration of Digestive Enzymes
3. Height/Weight/Body Fat%/and Lean Mass of the subject
4. Workout Rotuine
5. Genetics
6. Sleep Pattern
7. Goals
That being said, a 250 lb male at 10% body fat would require approximately 1g/lb of bodyweight worth of protein, MINIMUM to maintain a positive nitrogen balance and support anabolism, while working out. In conditions where his muscles will be constantly torn and forced to grow, 1.25g / lb would be closer to accurate.
The reason for this is 2 fold.
First of all, the body technically doesn't require THAT much protein, however you rarely will metabolize more than a percentage of the protein you consume. Certain proteins, such as whey, are HIGHLY assimilable, and thus are around 95-98% utilized, whereas other proteins, such as from black beans, only assimilate to around 50-60%. Google protein bioflavability for more on this.
Secondly, excessive carbs, without sufficient protein, will yield a high glycemic environment that will facilitate rapid fat gain, and/or hinder fat loss.
Dietary fat consumed acts as an anabolic agent (cholesterol) which promotes testosterone production, in addition to the obvious macro responsibilities.
To make a VERY long discussion short - 1g / lb of bodyweight is a "gold" standard because it's a catch all for "MOST" people. Some can get away with less, some can get away with more, but in GENERAL, it's a great baseline to establish for weight lifters attempting to gain mass.