Updated project metadata. The weight liver is one of the important selection criteria in the quality of foie gras. This factor is highly variable despite the fact that individuals are reared, force-fed and slaughtered in the same way. In this study, an analysis of the proteome profile of two weight classes of light (between 550 g and 599 g) and heavy (more than 700 g) livers. For the analysis of the proteic extracts, a liquid chromatographic analysis coupled with mass spectrometry was carried out. In livers with low weight, aerobic energy metabolism, protein anabolism and lipid metabolism oriented towards export and beta-oxidation was overexpressed. However, high weight livers was characterized by anaerobic energy metabolism, more active protein catabolism associated with cell death by apoptosis and reorganisation of the cell structure.