In order to investigate how to maintain normal weight under independent living conditions, twenty female university students were enrolled and asked to complete a questionnaire over a 10- day study period. T-test, Spearman's correlation and multiple regression analysis were applied to describe characteristics of weight maintainers'habits on a daily basis. The results were as follows: They always comsumed small or moderate-sized meals. 2~3 co-eaters usually had dinner together at home while not watching TV. They also showed healthy eating behaviors such as no snacking, very little amounts of soft drinks, coffee and alcohol consumption. The always normal weight maintainers, however, were not physically active at all. When being with co-eater(s), they ate larger-sized dinners (beta = 0.585, R2= 30.6), and the more co-eaters they had at the dinner table, the greater BMI they got (beta = 0.547, R2= 29.9). As a result of this study, encouraging young adult people to exercise on a regular basis is required, even though they seem to succeed in maintaining normal weight without being active physically. Further study is necessary to investigate how co-eaters would influence the amount of food eaten.