A 54-year-old man with a 12-year history of type 2 diabetes mellitus presents to the clinic for evaluation of poor glycemic control (HbA1c 9.8%) and a nonhealing plantar foot ulcer. He lives in an urban neighborhood characterized by high crime rates and a lack of full-service grocery stores. Instead, his nearest food options are several convenience stores and fast-food outlets. He reports that it is difficult to find fresh fruits and vegetables, and most of his meals come from these nearby sources. Which social determinant of health most directly contributes to this patient’s poor diabetes management?