The study, published in the Journal of Consumer Research, examined how individuals with different body mass indexes felt when exposed to thin or heavy media models.
"Underweight women's self-esteem always increases, regardless of the model they look at," the study authors said in a statement.
"On the other hand, overweight women's self-esteem always decreases, regardless of the model they look at."
The authors noted that overweight and underweight women showed comparable levels of self-esteem when they weren't looking at models.
Dirk Smeesters of Erasmus University in Rotterdam, the Netherlands, Thomas Mussweiler of the University of Cologne in Germany and Naomi Mandel of Arizona State University in Tempe recommended overweight consumers avoid looking at ads with any models -- thin or heavy.