Vietnam has designated 3.8 million hectares of agricultural land for paddy rice production, reflecting historical and ongoing concerns about food security. However, Vietnam is now the world’s second largest exporter of rice, and it imports vast quantities of livestock feed, some of which could be produced domestically if the land area restrictions were relaxed. Rather than improving food security, this policy may in fact increase malnourishment because some groups in the population lack a diversified diet. The Government has a plan to diversify into other crops. The implications of the Government land use policy for domestic consumers and producers of food, feed and livestock products are assessed in this paper with the aid of VAST, a dynamic, eight region, 13 commodity non-linear programming model of Vietnam’s agricultural sector. The reallocation of land currently designated for rice production would allow increased production of maize and a range of vegetable crops. However, the switch into feed products sold primarily on the domestic markets puts downward pressure on producer prices. The Government should remove restrictions on land use and let producers judge for themselves what products to grow.