[en] The influence of hole-hole (hh) propagation in addition to the conventional particle-particle (pp) propagation on the energy per particle and the momentum distribution is investigated for two central interactions (v₂ and v₂^l=0) which are derived from Reid's soft core potential. The results are compared to Brueckner-Hartree-Fock calculations with a continuous choice for the single-particle (sp) spectrum. Calculation of the energy from a self-consistently determined sp spectrum leads to a lower saturation density. This result is not corroborated by calculating the energy from the hole spectral function which is, however, not self-consistent. A generalization of previous calculations of the momentum distribution based on a Goldstone diagram expansion is introduced which allows the inclusion of hh contributions to all orders. From this result an alternative calculation of the kinetic energy is obtained. In addition, a direct calculation of the potential energy is presented which is obtained from a solution of the ladder equation containing pp and hh propagation to all orders. These results can be considered as the contributions of selected Goldstone diagrams (including pp and hh terms on the same footing) to the kinetic and potential energy in which the sp energy is given by the quasi-article energy. The results for the summation of Goldstone diagrams leads to a different momentum distribution than the one obtained from integrating the hole spectral function which in general gives less depletion of the Fermi sea. Various arguments, based partly on the results that are obtained, are put forward that a self-consistent determination of the spectral functions including the pp and hh ladder contributions (using a realistic interaction) will shed light on the question of nuclear saturation at a non-relativistic level which is consistent with the observed depletion of sp orbitals in finite nuclei. (Author) (51 refs., 3 tabs., 15 figs)