Nutrition Indicators for CGE Models

Computable general equilibrium (CGE) models have proven useful for simulating future economic activity and environmental indicators, especially in response to global drivers such as population, income, technology, and dietary preference. The focus of this paper is to show how output from CGE models can also be converted to nutritional indicators such as calories, carbohydrates, protein, fats, and micro-nutrients. This paper covers post-simulation analysis of food demand, rather than how to specify food demand within a general equilibrium model. There are strong links between the specification of food demand in a model, and how that is calibrated, to the realism possible for reporting calories and other nutritional indicators. It turns out that modification to the underlying social accounting matrix (SAM) can improve the realism of projections of food demand, by increasing the consistency between monetary units in the SAM and physical units (metric tons) in food balance sheets such as those published by the Food and Agricultural Organization (FAO) of the United Nations. If model output by food commodity can be expressed by weight (e.g., consumption in terms of grams per person per day), then food conversion tables can be applied to obtain a comprehensive list of nutrient consumption, including macro- and micro-nutrients. This information can be summarized in a variety of nutritional indicators. We cover two key steps: (1) pre-processing of the SAM and food balance sheets; and (2) post-processing of CGE model output.