In a sample of 1,442 white female workers, weighing 148.6lbs on average, the 5% who weighed 65lbs more than the 95% of the women in the sample earned 7% less on average than their thinner colleagues, when other factors, such as height, education, IQ, tenure and unemployment rates were statistically controlled.

However, evidence suggesting that overweight Hispanic women earn less than thinner women of the same group, was weak, and no evidence was found that the wages of overweight black women are affected.

In addition, no evidence that weight affects the probability of employment for white, black or Hispanic women, or the probability of holding a white-collar job, was found.

Researchers stress that the finding that weight lowers wages is not conclusive evidence of workplace discrimination, since another hypothesis consistent with the findings is that heavier workers are less productive at work.

Methodology

The study was based on the analysis of data in the National Longitudinal Survey of Youth on 2,843 white, black and Hispanic females over the 12 years to 1998.

The percentage of Americans who meet the clinical definition of obesity has risen from 15% in 1980 to 23% in 1990 to 26% in 1999.