Mark Roehling, professor of human resources at Michigan State University, said previous research found weight discrimination in schools, businesses, entertainment and other facets of U.S. society, so there is little surprise slender individuals might have an advantage at the polls.
"We found weight had a significant effect on voting behavior," Roehling said in a statement.
"Additionally, the greater size disparity between candidates, the greater the vote share of the more slender candidate."
Roehling and his wife, Patricia Roehling, a psychology professor at Hope College, analyzed data from the 2008 and 2012 U.S. Senate elections. Research assistants determined from color photos whether the candidates in 126 primary and general elections were normal weight, overweight or obese.
The study found both obese men and women were less likely to get on the ballot at all. In addition, when it came to merely being overweight, women were under represented on the ballot, but men were not.
However, male and female candidates -- whether obese or just overweight -- received fewer votes than their more slender opponents.
"The study provides evidence that the bias and discrimination against the overweight and obese
that has been documented in the areas of employment, education, healthcare and social situations also extends to the electoral process in the United States," Mark Roehling said.
The study was published online in the research journal Equality, Diversity and Inclusion.