Trade liberalization remains at the forefront of debates around globalization, particularly around the impact on agriculture and food. These debates, which often focus on how poorer countries can 'trade their way' out of poverty, pay limited attention to dietary health, especially in the light of the WHO's Global Strategy for Diet, Physical Activity and Health (2004), which warned that future health burdens will be increasingly determined by diet-related chronic diseases. This article examines the diet transition as the absent factor within debates on liberalizing trade and commerce. We describe the evolution of trade agreements, noting those relevant to food. We review the association between trade liberalization and changes in the global dietary and disease profile. We illustrate some of the complex linkages between trade liberalization and the 'diet transition', illustrated by factors such as foreign direct investment, supermarketization and cultural change. Finally, we offer three scenarios for change, suggesting the need for more effective 'food governance' and engagement by public health advocates in policy making in the food and agriculture arena.