I've also read elsewhere that the average Western diet contains twice the amount of protein you need. Too much protein comes with its own problems, in addition to just being stored as fat if it's more than the body can utilize. Perhaps strength trainers and bodybuilders use the extra protein as energy to build muscle, so that you could get the same energy from fat or carbs instead?
The same book said that the caloric ratio of the recovery shake or meal following strength training should be 4:1 calories from carbs and protein. I use soy protein powder, Powder Dextropur Plus, and water for my recovery shake. The high amount of carbs is to kick the body back from stress mode to recovery, and is only advised post heavy training when your body can handle it.
I really should find the title of the book, as it goes against a lot of wisdom found on the net. I just looked up ExRx.net [1] which I find is based on referenced science and facts, and they say:
* Average consumption for U.S. is 100 grams/day * Protein requirements 40 grams/day for females 55-70 grams/day or 0.8 grams/kg body weight for males * Recommended protein intake for athletes or physically active people (Paul 1989) Protein and carbohydrate requirements increase somewhat more calories
They say that protein and carb requirements increase somewhat when you're active, but further down on the page they say that the protein requirements may increase quite a bit. But it seems like the main requirement is a higher calorie intake, and that the ratio of calories from protein is basically the same for high-activity individuals.