Current thinking has it that obese people are obese because they engage in less physical activity and burn fewer calories than their thinner counterparts. But suppose you could show that obese women burn just as many calories as their thinner, supposedly fitter counterparts?
A study of African-American and Nigerian women, performed by Maywood, Illinois-based Loyola University Health System, shows that although the Nigerian women weighed considerably less than their American counterparts, both groups engaged in about the same amount of physical activity daily. The American women burned 760 calories per day, versus 800 by the Nigerians-a statistically insignificant difference.
This means, according to nutritionist Amy Luke, PhD, corresponding author of the study, that decreased physical activity may not be the prime culprit in the current U.S. obesity epidemic. Instead, what people eat appears to be the main factor in obesity.
The study looked at 149 Nigerian women from two villages in the countryside and 172 African-American women from metropolitan Chicago. The Nigerian women weighed an average of 127 pounds, while the African-American women averaged 184 pounds.
The researchers expected at the start of the study that the Nigerians’ lower weight was a result of greater physical activity. As the study progressed and they noted that both groups of women expended almost the same number of calories daily, they shifted their attention to diet as the main determinant of obesity.
The Nigerians ate a low-fat, low animal protein diet high in fibers and complex carbohydrates. The Americans ate a diet rich in processed foods, in which fat accounted for up to 45 percent of all the calories taken in.
Although the Loyola study shows that lack of physical activity may not be quite as strong a factor in obesity as previously believed, the benefits of physical activity remain proven, especially for people with diabetes: lower blood pressure; improved cholesterol levels; reduced risk of cardiovascular disease; lower blood sugar levels; enhanced mood; and improved muscle tone.