Researchers from Loyola University compared African American women in Chicago with women in rural Nigeria. On average, the Chicago women weighed 184 pounds and the Nigerian women weighed 127 pounds. Researchers had expected to find that the slimmer Nigerian women would be more physically active. To their surprise, they found no significant difference between the two groups in the amount of calories burned during physical activity. We would love to say that physical activity has a positive effect on weight control, but that does not appear to be the case, said one of the researchers.