In a naturalistic study, we investigated the influence of gender, group size and gender composition of groups of eaters on food selected for lunch and dinner (converted to total calories per meal) of 469 individuals (198 groups) in three large university cafeterias. In dyads, women observed eating with a male companion chose foods of significantly lower caloric value than those observed eating with another woman. Overall, group size was not a significant predictor of calories, but women's calories were negatively predicted by numbers of men in the group, while the numbers of women in the group had a marginally significant positive impact on calorie estimates. Men's calorie totals were not affected by total numbers of men or women. This study supports previous investigations, but is unique in making naturalistic observations.