Physics question about fighter jets?

While sitting on the toilet as usual for my life, I was thinking about… ah, I’ll keep it to myself, but it did raise some other questions:

When an aircraft makes a 9g turn, that aircraft more or less tends to bleed airspeed, or energy, very fast. What is it that makes the aircraft lose that energy? The g-load on the aircraft? The high angle of attack?

So if that plane suddenly weighed only half it’s original weight right there and then pulled a nine-g turn, would the resultant airspeed bleed only be at half it’s normal rate as well?

Alternately, if a plane pulled a 9g turn but only experienced 4.5g of force on the aircraft, how would THAT effect it’s airspeed bleed? Or hell, it’s flight performance?

If you’re a major science fiction nerd, I think you’ll know what I’m getting at here…