Thrifty Food Plan 2021 Optimization Model
By: U.S. Department of Agriculture, Food and Nutrition Service, Center for Nutrition Policy and Promotion

Description:
This folder contains all inputs and code necessary to run the optimization model used in the development of the Thrifty Food Plan (TFP), 2021.

The model is an optimization model minimizing the deviation of the model solution for consumption from observed consumption. 
The cost constraint is set at an initial level and adjusted iteratively to find the lowest-cost solution that satisfies all dietary, cost, and practicality constraints. 

The model is developed in the file 'TFP_2021_Public.gms' and reads in data and other information that are stored in .csv or .inc files in the folder 'inputs'.
The 'outputs' folder stores the model results, or output of TFP_2021_Public.gms and will be updated as model iterations are run. 
The TFP model creates Market Baskets that contain a variety of commonly consumed foods and beverages that are lower in price and of 
higher nutrition quality (or nutrient density) to support healthy meals and snacks at home on a limited budget.

The optimization model’s output is in the form of daily quantities of foods and beverages in 98 modeling categories. 
To calculate the weekly amounts in the Market Baskets presented in the TFP, 2021 report, the results need to be 
further processed using the Purchase to Plate Crosswalk (Carlson et al., 2022).

The code was developed using GAMS version 34.3.0 and GAMS Studio version 1.5.4.

File and folder organization:
TFP_2021
- TFP_2021_Public.gms
- readme.txt
- inputs
	- data.inc
	- set_agesex.inc
	- set_foods.inc
	- set_nutrients.inc
	- in_combined_category_prices.csv
	- in_cost_constraint.csv
	- in_FPED_nonpattern_amounts.csv
	- in_high_DQ_consumption_combined.csv
	- in_high_DQ_consumption_SDs.csv
	- in_nutrient_composition.csv
	- in_nutrient_constraints.csv
	- in_prices.csv
	- in_sodium_intake.csv
- outputs
	- out_nutrient_dual.csv
	- out_result_TFP.csv
	- out_feasibility.csv
	- out_result_nutrient_contribution.csv


References:
Carlson, A. C., Tornow, C. E., Page, E. T., McFadden, A. B., & Zimmerman, T. P. (2022). Development of the Purchase to Plate Crosswalk and Price Tool: Estimating prices for the National Health And Nutrition Examination Survey (NHANES) foods and measuring the healthfulness of retail food purchases. Journal of Food Composition and Analysis, 106, 104344.
Dietary Guidelines for Americans, 2020-2025: https://www.dietaryguidelines.gov/sites/default/files/2020-12/Dietary_Guidelines_for_Americans_2020-2025.pdf
Thrifty Food Plan, 2021 report: https://fns-prod.azureedge.us/sites/default/files/resource-files/TFP2021.pdf