When people share big plates of food, from which everyone takes as much as he/she wants to eat, the last portion on the plate is often left untouched due to everyone’s hesitation. This study observed eating behavior in 21 groups; each group had three people sharing five big plates of food. In total, 11 groups, with all members familiar with each other （friend condition）, and 10 groups, with all members unfamiliar with each other （stranger condition）, participated in the study. In each group, the members were all of the same gender and, with the exception of one group, all were of the same age. By comparing these two conditions, this study aimed to examine whether people change their serving behavior depending on their relationship with the people they are sharing the food with. It was shown that in both the conditions, people stopped helping themselves to certain foods, that is, fried chicken and fried rice, at the final stage of the meal. The total amount of food eaten by each individual was less equal in the friend condition than in the stranger one. Deciding who would eat the remaining food by "janken” was only observed in the friend condition. These results suggested that when people share food with strangers, food is more equally distributed amongst the members compared to when people share it with friends.