The aim of this study was to investigate the clinical relations of eating behaviors to body mass index (BMI) and obesity in girls with idiopathic central precocious puberty. This study included 30 precocious puberty patients who were diagnosed at Chosun University Hospital between February and December 2013. Information was obtained from their parents using a questionnaire focused on eating behaviors and lifestyle factors. We rechecked their BMI and questionnaire after 12 months to identify the changes. Six (20%) of the 30 patients children were overweight and obesity at diagnosis. Overweight and obesity group tended to overeat. Normal weight group ate an unbalanced diet more than overweight and obesity group, particularly lack of fruit and vegetable (p=0.010). Eight (27%) of the 30 patients children were overweight and obesity and 24 (80%) of the 30 patients children showed increased BMI after 12 months follow up. BMI-decreased group ate breakfast with whole family members more frequent than BMI-increased group (p=0.006). This study showed the importance of healthy diet during treatment of precocious puberty. Children with precocious puberty should avoid overeating and make a balanced diet with preferable eating behaviors from the family meals.