Smart Money has produced a most instructive display of the cost of 100 calories in meals at fast food restaurants. Click on the numbers starting with #1 (for which you have to click on #2 - the numbers are off by 1 for some reason). #1 is the most expensive: $1.47 per 100 calories for at McDonald's Southwest Salad with Grilled Chicken. # 13 (click on #14) is a Burger King Double Whopper with Cheese at 49 cents for 100 calories but you have to buy 1010 calories at this price. The cheapest, #15 (click on #16) is a 32-ounce Coca-Cola at 38 cents per 100.

Even with glimmers of hope for the recovery, consumers are still cutting back -- especially when it comes to dining out. But turning to some of fast food's biggest bargains in order to stretch your dollar in the recession may be one belt-tightening measure that could end up forcing you to loosen your buckle by a couple of notches.

Going out for cheap eats is an obvious way for consumers to keep their spending in check. That's why fast food restaurants are seen as a good investment in tough times. McDonald's (MCD: 54.31, -0.99, -1.79%) and Yum! Brands (YUM: 34.87, +0.35, +1.01%), which operates Taco Bell, KFC, and Pizza Hut (among others) both reported stellar fourth quarters as proof. Bucking that trend were Burger King (BKC: 18.59, -0.31, -1.64%) and CKE Restaurants (CKR: 9.85, +0.10, +1.02%), the operator of Hardee's and Carl's Jr. Burger King reported that it experienced "significant" traffic declines in March (it reported 1% same-store sales growth) and CKE's same-store sales were down 2.7%. Nevertheless, that slide is still modest when compared with the double-digit losses at higher-end restaurant chains like Ruth's Hospitality Group's (RUTH: 2.74, +0.64, +30.47%) Ruth's Chris Steakhouse and Benihana (BNHN: 5.05, +0.77, +17.99%).

It would be interesting to do the same thing for nutritional value. Could nutrients (other than calories) be proportional to cost? That idea might be worth a closer look.