The cereal wars have found a new battlefield, and the nation's hungry stand to benefit from the conflict. Both Kellogg (NYSE: K) and General Mills (NYSE: GIS) have agreed to make contributions to the not-for-profit organization Feeding America (formerly known as Second Harvest), which supplies food to more than 25 million Americans each year. But not all contributions are equal.

Kellogg is donating one entire day's production, around 55 million servings, to the organization. It places the value of this donation at $10 million. This figures out to $.18 cents per serving, about half of the shelf price. Starting June 17th, the company will also send you $5 of coupons for every $5 you donate to Feeding America.

There is an old phrase, "Doing well by doing good." Show the public what a nice guy you are and people will be more likely to do business with you.

According to The New York Times, "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." That seems like a lot of food, probably because it is.

Wal-Mart's (NYSE:WMT) new program will certainly help the poor but it may not bring the retailer more sales. There may be some good PR in it, but there's no guarantee that the initiative will help bring in customers at all. In that way, it is truly charitable.

A number of big companies give money to museums and the arts. Many encourage their employees to contribute to the United Way or help out on community projects. But it would be hard to find something which has such a direct benefit as feeding people who cannot feed themselves.

Wal-Mart has take its share of beatings in the press. It ought to get a lot of credit here.

Douglas A. McIntyre is an editor at 247wallst.com.