Responding to the economic downturn, Wal-Mart Stores Inc. plans to give more than 90 million pounds of fresh food annually to the nation’s largest nonprofit organization addressing hunger, Feeding America.

The program, which is being formally announced on Wednesday, comes as food banks across the nation are reporting increased demand, though Margaret McKenna, president of the Wal-Mart Foundation, which oversees the company’s giving program, said the gift would continue far beyond the immediate crisis.

“We are a strong company, and we share what we have with people in need,” Ms. McKenna said.

The company will not seek a tax deduction for its gift, she said, and thus could not estimate its dollar value.

Wal-Mart’s annual donation will account for more than 4 percent of the roughly 2.2 billion pounds Feeding America, formerly known as America’s Second Harvest, distributed last year. Vicki Escarra, president and chief executive of the organization, said it planned to increase that amount to 3 billion pounds a year over the next four years.