Scudrunners

The other thread about climb speed got me thinking about this.  Let's say sometime after takeoff the fan stops turning and you want to be as efficient as possible.  For a bare minimum energy loss, how aggressively do you put the nose down?  Would pitching down at zero G technically work best as you'd be on a parabolic trajectory, possibly with no induced drag during the maneuver?

I may be over thinking this.