Peer relationships play a critical role in academic performance, yet their link in higher education remains underexplored. This study introduces commensality--shared mealtimes--as a novel proxy for peer acceptance and examines its relationship with academic outcomes across student groups. Using 2,717,938 transaction records from 3355 first-year undergraduates at a prestigious Chinese university, we developed "commensality value" metrics to quantitatively measure peer relationships. Regression analyses reveal that peer acceptance, particularly from peers who are more physically distant, is positively correlated with academic performance. This correlation is stronger among male students, politically active students, former class leaders, and those with politically active parents. These findings highlight the potential benefits of strong peer relationships and suggest that promoting environments that encourage peer commensality could be a valuable strategy for universities to explore. By bridging gaps in the literature, this study introduces innovative metrics and advances the understanding of the peer academic success.