A new study co-authored by a Michigan State University scholar finds that overweight and obese women are significantly underrepresented among the top CEOs in the United States. On the other hand, while obese men were also underrepresented, overweight men were actually overrepresented among top CEOs.

The different results for women and men suggest weight bias may contribute to the glass ceiling on the advancement of women to the top levels of management.

The study results suggest that while being obese limits the career opportunities of both women and men, being 'merely overweight' harms only female executives - and may actually benefit male executives. Such pattern of findings is consistent with previous researches indicating that, at least among white Americans, there is a tendency to hold women to harsher weight standards.

For the study, two groups of experts analyzed publicly available photos of CEOs from Fortune 1000 companies. The expert raters included individuals who were tested prior to the study to determine their accuracy in assessing body weight based on photographs, and medical professionals who by virtue of training and experience are experts at weight estimation.

It has been found that only 5 % of male and female CEOs at top companies were obese, which is much lower than the U.S. average of 36% for men and 38 % for women of similar age.

The study also shows that between 45 % and 61 %of top male CEOs are overweight , which is higher than the U.S. average of 41% in similarly aged men. That means overweight men were actually overrepresented in top CEO positions.

On the other hand, only 5% to 22% of top female CEOs were overweight, compared with the U.S. average of 29% among similarly aged women.

The study researchers conclude that that there is a greater tolerance and possibly even a preference for a larger size among men but a smaller size among women.

Glass ceiling effect on women's advancement may reflect not only general negative stereotypes about the competencies of women, but also weight bias that results in the application of stricter appearance standards to women.