Unless deeply buried underground. In the countryside there would be natural resources to draw upon. In large cities shops would soon be emptied of food, sold or looted. And plants in parks and gardens would be rapidly stripped once any private stocks had been exhausted. The population would have to make forays out into the countryside to survive, or abandon the town, if not in a siege situation.
Suburban dwellers have more vegetable plots and open spaces to provide foodstuffs.
They would be less dependent upon shops. Those away from major centres are more likely to have their own food stocks because they cannot shop at will. But most of them will be reluctant if not dangerous to deal with. Most families have some food in store. It should be rationed and supplemented with whatever can be found.