Rapid income growth and urbanization in China has triggered a dietary transition towards more animal based products such as meats and dairy products. This transition has already had significant impacts on nutritional and health outcomes. The purpose of this paper is to assess the nutritional and health outcomes of diet transition and alternative diets on the one hand and the associated agricultural and food production and trade effects on the other hand, using the Chinese case as an example. We base this analysis in a modified GTAP model featuring the demand, production and supply and trade of major agricultural and food products. Taking advantages of recent methodological advances in building calorie and other nutrition data sourced from the FAO into the GTAP model and database, we further represent current and predicted dietary patterns for China in a baseline projection. The projected dietary patterns (defined on both nutritional contents as well as on compositions of product sources) mainly follow the income-driven transition path as reported in recent literature. Then in the alternative scenarios, we impose on the baseline several distinct diets according to official diet guidelines such as those from the WHO and the Chinese health authority, as exogenous changes to consumer demands via shifts of consumer preferences. Simulations of these scenarios will then reveal the production and trade pattern changes that are necessary to accommodate the demand shifts, as well as the associated efficiency and welfare consequences. Realizing that changing dietary trends are likely to be costly, in a more refined scenario, we consider public policy options to influence consumer choices for purposes of reaching a given alternative diet target. Since the costs of the policy intervention will be captured in this case, the welfare cost of an alternative diet will then be fully accounted for.