Feel like snacking on an Arby's BLT sandwich? Get ready to rake in 780 calories and 46 grams of fat. Want to sip on a McDonald's strawberry shake? The largest—32 ounces—packs 1,120 calories. Even your favorite old-fashioned cake doughnut isn't safe: 300 calories, 170 from fat. Fast-food restaurant menus are laden with high-calorie foods, and fast food's popularity with Americans has sometimes been blamed for this country's obesity epidemic. Americans now spend more than $110 billion a year on fast food, but some areas of town could be eating up more than their share of that number. Researchers from Tulane University and Louisiana State University looked at where fast-food joints were located in New Orleans to see if some areas were being fed more of a mouthful than others.

What the researchers wanted to know: Do some neighborhoods have a higher concentration of fast-food restaurants than others?

What they did: The researchers included 14 different fast-food chains popular in New Orleans, from Bud's Broiler to Wendy's Old-Fashioned Hamburgers, in their analysis. They looked up the addresses of all store locations in the phone book, online, or through the Sanitation Department (which inspects restaurants), then plotted the locations on a computer-map. They analyzed the location of fast-food restaurants by census tract and used census information already collected to measure income level and the ethnic and racial makeup of each neighborhood.

What they found: Fast-food restaurants in New Orleans were more likely to be located in low-income or black neighborhoods. In neighborhoods where 80 percent of the population was black, there was an average of 2.4 fast-food places per square mile; in neighborhoods with a 20 percent black population, that number decreased to 1.5 restaurants per square mile. Income level was not as strong of a predictor as the racial makeup of the neighborhoods; still, lower-income neighborhoods had more fast-food restaurants in their vicinity.

What it means to you: More-convenient access to fast food usually leads to eating more of it. That can be harmful to your health, especially eating the huge portions and high-fat food available at most fast-food outlets. This study shows that blacks and low-income people, at least in New Orleans, may be at a higher risk for becoming overweight because it is easier for them to get fast food.

Caveats: First, this study focused only on the city of New Orleans; it can't necessarily be generalized to other areas. Second, other studies have not shown a relationship between wealth and fast-food restaurants, though the authors point out that at least one of the most often cited studies used a different method from theirs.

Find out more: A number of websites have nutritional information from popular fast-food restaurants. Among the easiest to use are: www.foodfacts.info and www.chowbaby.com.

Read the article: Block, J.P. et al. "Fast Food, Race/Ethnicity, and Income." American Journal of Preventive Medicine. October 2004, Vol. 27, No. 3, pp. 211–217.

Abstract online: www.ncbi.nlm.nih.gov