This is a randomized prospective study into metabolic adverse events during initial antiretroviral therapy in HIV-1-infected men. The following regimens are compared: lopinavir-ritonavir + Combivir and lopinavir-ritonavir + nevirapine (nucleoside reverse transcriptase inhibitor [NRTI]-sparing). Prior to the start of therapy and 3, 12, 24, and 36 months thereafter the distribution of body fat and bone density (bioelectrical impedance analysis [BIA], computed tomography [CT] and dual energy x-ray absorptiometry [DEXA]), lipid spectrum, mitochondrial DNA (peripheral blood mononuclear cells [PBMCs] and adipose tissue biopsies) and vascular measurements are performed. In addition, insulin sensitivity is measured in a subgroup of sixteen individuals by using a hyperinsulinemic euglycemic clamp and performing microvascular measurements. The aim of the study is to obtain prospective insight into the occurrence of various aspects of metabolic adverse events on the one hand and to compare an NRTI-containing therapy with an NRTI-sparing therapy on the other hand. The hypothesis is that in the NRTI-sparing arm, less metabolic and vascular changes are observed than in the NRTI containing regimen.