Nielsen, a research and consulting firm, said last month that for the first time in a decade, shoppers were making more trips to stores, but coming out with less in their baskets. “They’re not stockpiling their pantries as much,” said Jordan Rost, the company’s vice president for consumer insights. “They’re really buying more fresh produce and prepared meals.”

Mr. Ruhlman predicts that much of what is sold in the center of the store — the cereal, canned soups, detergents and Ziploc bags — will be largely bought online in the not-too-distant future as food shoppers become more accustomed to e-commerce.