Years ago I tried Dan Duchaine's Body Opus diet, and I must admit that it did work fantastic in terms of getting lean and building muscle at the same time. I believe the ratios were 30% Protein and 70% fat with zero carb for five days, and then two days of VERY high carbohydrate and moderate protein.
The problem with this was just that it was SO hard to stick with. My weekends were consumed by eating corn flakes and whey every 2.5 hours and it made it very hard to have any sort of social life with the timing, strange foods, and strictness of it all. In the end, I just ended up giving things up.
Was wondering what kind of diet (ratios/ grams/ etc) that you have found to be optimal for gaining muscle while staying lean as a natural?