  We use the recently introduced single-particle states obtained from localized
Deuteron wave-functions as a basis for nuclear many-body calculations. We show
that energies can be substantially lowered if the natural orbits obtained from
this basis are used. We use this modified basis for ${}^{10}B$, ${}^{16}O$ and
${}^{24}Mg$ employing the bare $NNLO_{opt}$ Nucleon-Nucleon interaction. The
lowering of the energies increases with the mass. Although in principle natural
orbits require a full scale preliminary many-body calculation, we found that an
approximate preliminary many-body calculation, with a marginal increase in the
computational cost, is sufficient. The use of natural orbits based on an
harmonic oscillator basis leads to a much smaller lowering of the energies for
a comparable computational cost.
