A NUMBER OF STUDIES FIND EVIDENCE OF NUTRITIONAL INEQUALITY IN THE UNITED STATES--THAT IS THE ASSOCIATION BETWEEN LOW ACCESS TO HEALTHFUL FOOD AND LOW INCOME OR NON-WHITE POPULATION. HOWEVER, THE FINDINGS ARE NOT CAUSAL: WE DO NOT KNOW WHETHER THE RESIDENTS OF THE LOW-INCOME NON-WHITE NEIGHBORHOODS ARE CHOOSING UNHEALTHFUL DIETS BECAUSE OF THE LACK OF ACCESS, OR LARGE FOOD RETAILERS WITH A VARIETY OF HEALTHFUL OPTIONS CHOOSE NOT TO LOCATE IN THE NEIGHBORHOOD DUE TO LACK OF DEMAND. THE CURRENT PROJECT CONDUCTS AN IN-DEPTH ANALYSIS FOR POLICY GENERATION. FIRST, WE DERIVE THE CONDITIONAL PROBABILITIES OF EACH TYPE OF FOOD RETAILER, E.G., GROCERY, FAST-FOOD RESTAURANTS, THAT LOCATES IN A CERTAIN REGION, GIVEN THE DEMOGRAPHIC AND REGIONAL FEATURES. WE USE CELLPHONE MOBILITY DATA TO TRACK AVAILABLE FOOD OPTIONS IN A REGION, AND MACHINE LEARNING MODELS FOR IMPROVED PREDICTION. SECOND, WE CALCULATE THE RATE OF SUBSTITUTION BETWEEN TWO TYPES OF FOOD RETAILERS TO UNDERSTAND THE DIETARY PREFERENCES OF RESIDENTS. IF ONE TYPE OF FOOD RETAILER IS PRESENT, WE ASSESS HOW IT AFFECTS RESIDENTS' DIETARY AND NUTRITIONAL CHOICES, SUCH AS FRESH VEGETABLE CONSUMPTION. WE USE COVID-19 LOCKDOWN AND STORE CLOSURES TO OBTAIN THE CAUSAL INFERENCE. HOUSEHOLD FOOD PURCHASE INFORMATION WILL BE OBTAINED FROM SCANNER DATA. FINALLY, WE EVALUATE THE IMPACT OF THE PRESENCE OF VARIOUS FOOD RETAILERS AND THEIR COMPOSITION IN THE NEIGHBORHOOD ON DISEASES THAT MIGHT BE INFLUENCED BY DIETARY CHOICES, SUCH AS DIABETES, OBESITY, AND CARDIOVASCULAR DISEASES. THE PROJECT WILL CONTRIBUTE TO RETAIL FOOD POLICY AND HEALTH POLICY IN THE UNITED STATES. UNDERSTANDING THE SUBSTITUTION BETWEEN FOOD RETAILERS WILL HELP TO DESIGN A RESILIENT LOCAL FOOD SECTOR THAT MIGHT COMBAT A FUTURE DISEASE-INDUCED PANDEMIC.