The one-third rule, which sets tight wholesale and retail limits for food products, is arguably a primary cause of huge food waste in Japan. However, the effect of relaxing the limits was found to vary depending on some conditions. Thus, to further understand how these limits affect food wastage, we take a game-theoretical analysis approach. In this approach, we formulate a normal-form game played by a manufacturer and a retailer in a milk supply chain, develop a simulation model of the chain, and use the simulator to obtain sample values of the players’ payoffs earned under every pair of their strategies. We then apply a statistical multiple comparison test to the data to identify the statistical best responses of a player to each opponent strategy, derive statistical Nash equilibriums, and compare the equilibriums obtained under different limits and consumers’ preferences. Consequently, it is confirmed that relaxing the limits may undesirably impact food waste.