Adrian E. Tschoegl of the Wharton School of the University of Pennsylvania, has recently published an article in the Global Economic Journal entitled "McDonald's -- Much Maligned, But an Engine of Economic Development." In the paper he argues that McDonald's has very beneficial economic effects:

Critics have excoriated the US fast-food industry in general, and McDonald's most particularly, both per se and as a symbol of the United States. However, examining McDonald's internationalization and development abroad suggests that McDonald's and the others of its ilk are sources of development for mid-range countries. McDonald's brings training in management, encourages entrepreneurship directly through franchises and indirectly through demonstration effects, creates backward linkages that develop local suppliers, fosters exports by their suppliers, and has positive external effects on productivity and standards of service, cleanliness, and quality in the host economies.

I have no doubt that if he studied the effect of Wal-Mart on local and global economies, he'd find the all of the above and then some, but without the effect on the waistline and cholesterol levels.