Abstract The purpose of this study was to examine whether or not the presence of an overweight eating companion influences healthy and unhealthy eating behavior, and to determine if the effect is moderated by how the companion serves herself. A professional actress either wore an overweight prosthesis (i.e., “fatsuit”) or did not wear one, and served herself either healthily (i.e., a small amount of pasta and a large amount of salad) or unhealthily (i.e., a large amount of pasta and a small amount of salad) for lunch. After observing her, male and female participants were asked to serve themselves pasta and salad to eat. Results demonstrated that regardless of how the confederate served, participants served and ate a larger amount of pasta when she was wearing the prosthesis than when she was not. In addition, when the confederate served herself healthily, participants served and ate a smaller amount of salad when she was wearing the prosthesis than when she was not. Consistent with the “lower health commitment” hypothesis, these results demonstrated that people may eat larger portions of unhealthy food and smaller portions of healthy food when eating with an overweight person, probably because the health commitment goal is less activated. More generally, this study provides evidence that the body type of an eating companion, as well as whether she serves herself healthily or unhealthily, influences the quantity of food intake.