Oh, hehe.
It doesn't actively discourage it, but it doesn't encourage it as per veggy does.
Imagine a veggy with 1000 body reproduces. The veggy and kid are going to be making the same nrg per cycle as the veggy did before reproducing.
Now imagine it's per veggy. The veggy and kid are going to be making more nrg per cycle than the parent did. The very act of reproducing has increased the amount of nrg coming into the sim.
If you select the quadratically based on body thing, you'll actually actively discourage veggies from reproducing, especially if the veggies are quite large. Reproducing will actually decrease the amount of nrg coming into the sim.