Quote[/b] ]Actually, most guys take in too much protein. It isn't that too much protein will hurt them - assuming they are healthy to begin with - but too much protein can actually inhibit gains. I know, it sounds totally contradictory to what you read everywhere, but it is true. Let me explain.
The ability of the body to grow is effected by the ratio of protein to carbs. It is an inverted U shaped curve - or bell curve - where the top or highest point of the curve is a ratio of 12-15% protein to carbs (diet consisting of ~15% protein). At one peak you have all carbs, at the other you have all protein. It has to do with thermogenesis and hormones.
So, if a skinny guy wants to gain weight, he needs to plan a diet where he gets 15% of his calories from protein.
Now this may seem contradictory to the general rule of 1 gram per pound bodyweight. I'm not saying that a guy can't gain weight with more than 15% calories from protein, I'm only saying that weight gain is greatest at 15%. He will be ok with an intake of 0.75 grams/pound FFM to gain muscle. In fact, everybody should use FFM instead of bodyweight to plan protein intake, but sometimes it's just too hard to figure it out, so most people use bodyweight.
For a guy who isn't all that skinny, or even a little fat, he should increase his protien intake to 20-25%. This will increase thermogenesis and prevent some fat gain as calories increase above maintenance.
The problem with protein cycling is that it is hard ot get ahead of your body when it comes to managing protein. The body adapts fairly quickly to changes in protien intake. If you eat more during the day, your body will get rid of more during the night. That changes according to intake on a daily basis.
Longer term, your body will adjust to a drop in protein intake over the course of 12-14 days. In other words, you will go into a negative nitrogen balance on day one, and it takes about 12-14 days for your body to be able to reeduce protein breakdown to the point of reaching balance again.
Some may argue about the different turnover rates of muscle protein and splanchnic proteins. This should have led to real success from protein cycling, yet it hasn't.
If you do decide to cycle your protein, I would not drop your intake below 15% (or ~1g/kg bodyweight) while maintaining total calories. Then keep protein intake at this lowered level for at least 2 weeks.
Your diet can effect Test and IGFBPs. IGFBPs dictate how much IGF-1 is actually available for your body. Too much protein relative will lower insulin, and thus available IGF-1 and free test levels. Too little fat will also lower test levels. Keeping fat at 30% of total calories is optimum for testosterone.