According to life cycle assessment (LCA), meat from ruminant species has a higher environmental impact per kg of protein than meat from monogastric species. Conversely, the framework of ecosystem services (ES) indicates that ruminant farming systems can provide higher levels of regulating ES (e.g. water purification). We applied both approaches to twelve contrasting meat production systems (six ruminant, six monogastric). The LCA was applied using two ‘functional units’: i) the quantity of protein produced (kg) and ii) the land area used to produce the meat (m²/year). Our results confirm that, per kg of protein, ruminant systems emit more greenhouse gases and consume more energy than monogastric systems, but the opposite is observed of land area. Ruminant systems also provide more regulating ES, thanks to their grasslands. Our study reveals that LCA and ES approaches can converge or diverge depending on the functional unit used.