It's really boils down to a trade-off between speed of lean gains and how delicious you want your dinner to be. I've gained muscle quickly for a female eating around 100-120 g of rice (by dry weight) with a couple of cups of veg fried in about 20 g of fat plus some oily fish and or cheese as my typical post-workout meal. So in my personal experience, eating low fat has not been critical.
Optimisation is fine if you want it and enjoy experimenting on yourself... and it does becomes more important as you get closer to reaching your goal.
F 5 ft 3. HW: 196 lbs. Primal SW (May 2011): 182 lbs (42% BF)... W June '12: 160 lbs (29% BF) (UK size 12, US size 8). GW: ~24% BF - have ditched the scales til I fit into a pair of UK size 10 bootcut jeans. Currently aligning towards 'The Perfect Health Diet' having swapped some fat for potatoes.