That knock on the door comes a million times a day as Meals on Wheels volunteers fan out in their communities to deliver food. Some drive great distances in rural areas, some around their own neighborhoods.

The meals are tailored for the elderly, and often for diabetics. Sometimes they are delivered hot and ready to eat. Sometimes they need to be heated in a conventional or microwave oven. Sometimes they reflect regional tastes. All the meals are manna to the recipients.

According to Ellie Hollander, CEO of Meals on Wheels America, based in Arlington, Va., the average recipient is 75 years old or older, is usually a woman, takes at least six medications a day, suffers some physical impairment, and wants to live independently.