Brazil and macadamia nuts (Bertholletia excelsa, Macadamia integrifolia) boast impressive mechanical resilience. Compressive fracture tests revealed a foam-like behavior of the shells. To identify key structural features explaining this deformation pattern, we combined performed numerical simulations and validated these by compression tests. The finite element models reveal a strong influence of geometry, where very small changes have major impacts on the stress distribution and deformation. Notably, circumferential tensile stresses play a crucial role in failure. They further show that voids and vascular bundles in the shell act as stress-redistributors, enhancing overall strength by impeding crack propagation. This unique porosity inspires lightweight materials with strategically placed pores, potentially leading to enhanced mechanical performance.