Here's the view from a frioend of mine who's opinion I value highly.
"I disagree with the mainstream bodybuilding community that supports higher protein diets for several reasons. This is going to be a choppy presentation rather than a smooth dialogue.
First it’s important to understand some basic nutritional biochemistry.
After proteins are broken down into their constituent amino acids your body reassembles amino acids in specific orders for specific functions. Once the reassembled proteins are used for their purposes, amino acid residue, the portion of the amino acid that is left over after the nitrogenous portion has been stripped away, is either glycogenic (capable of converting to glucose) or ketogenic (capable of converting to ketones). Only three amino acids are ketogenic. Through a process known as gluconeogenesis the residue is converted to glucose, contributing to the overall energy demands. Therefore, excess protein above what your body requires for building and repairing structural tissues is converted into glucose and utilized for energy or stored as fat.
Hence, positive nitrogen balance refers to an environment positive for growth since excess nitrogen is excreted by your body through your urine, feces, etc. Positive nitrogen retention indicates an upper limit of protein intake for the purpose of building and repairing structural tissues.
Most reliable resources of information that do not profit from the sales of supplements have found that the upper limit of protein intake for strength athletes is 1.1 to 1.5 grams of protein per kilogram of body weight, assuming a lean condition. Surprisingly long duration aerobic athletes require more protein than strength athletes for gluconeogenesis. Check the latest DRI research for more information.
Therefore, a massively built bodybuilder such as Mentzer who weighed in around 215lbs requires 110 to 150 grams of protein per day to maintain and build his muscles. Interestingly enough, through phone and email conversations I had with Mentzer, I learned that he consumed between 75-100 grams of protein per day during his ’79 (?) competition against Arnold. In other words, this drug abusing heavyweight managed to exceed the development of most trainers in the world and on this forum (I assume) consuming as little as 1g/kg or 0.45g/lbs of protein per day.
An additional argument against high protein diets is the protein needs of an infant. Protein needs are highest during the first year of birth. Infants will double their birth weight in the first six months and triple birth weight during the first year. No bodybuilder, steroids or no steroids, would be able to match these enormous changes. Yet an infant requires around 2.2 grams of protein per kilogram or 1 gram of protein per pound of bodyweight. Teenagers aged 15 to 18 years also undergo rapid muscular growth during puberty and require 50-60 grams of protein per day. Relative to an infant or teenager, most advanced bodybuilders do not grow nearly as much. Its doubtful that the daily protein requirements exceeds an infants. Furthermore, the weight of muscle is mostly water, approx 70%, so why wouldn’t drinking more water lead to larger muscles?
The truth is that you can’t force your body to utilize more protein above its needs. Its no different than vitamin c, mega-dosing vitamins is not any more productive, the excess is excreted. With protein, the excess is converted into glucose or ketones, and stored or burned. Only if the diet is deficient will supplementation provide a benefit. Besides, there is no guarantee that the additional protein will be utilized to build the structural tissues. For amino acids to be used specifically for protein synthesis they must be capable of, and combine with, specific enzymes used to facilitate the process. Why not look into consuming more enzymes?
Few athletes look at the unity of the organism. They fail to have a holistic approach, looking for a singular cause of specific results, rather than looking at a single process in its relationship to a whole. So you have bodybuilders that just count protein and calories, but are deficient in vitamins, minerals, and essential fats. This is an indication of a lack of education, or at least not reading scientifically based textbooks but profit orientated magazines."
Now a lot of people will have different opinion through different experiences, but the totals I posted above have worked for me for a long time. Your body will be difrerent so you might need more or less, but nowhere near 450g/day.
