As evidenced from the Korean archaeological record, there is an increased use of plant domesticates and a decrease in other food sources during the Holocene. These changes in overall human diet breadth culminate with the Late Neolithic–Bronze Age (c. 3500 B.P.) transition where dependence on hunted and gathered food packages decreases during the former period and full-scale agriculture becomes the norm during the latter cultural stage. This dietary shift appears to coincide with Holocene shoreline stabilization and overall large-scale population increase and movement through time. It is proposed here that two primary reasons exist for the change in overall diet breadth: (1) increasing shoreline stabilization during the Holocene and (2) an increase in hunter-gatherer population pressure due to a sedentary lifestyle. Both of these factors would have led to some degree of territorial circumscription, resulting in a progressive decline in overall hunter-gatherer foraging e‰ciency. In turn, this would have prompted the Holocene Korean Peninsular peoples to find other ways to offset their lowered overall foraging efficiency that had originally focused primarily on higher-ranked food resources (e.g., deer, wild boar). In this case, Korean peoples expanded their overall diet breadth to include a lower-ranked set of food packages (e.g., fish, shellfish) that by the advent of the Bronze Age eventually included plant domesticates regularly.