The population of the study consists of overweight and obese students studying in 5th, 6th and 7th grades of secondary school. However, due to the very large population, 3 secondary schools were selected. It was decided to select a sample from these three secondary schools.The children included in the sample were likely to be in different groups. Also, no intervention would be applied to children in the control group. There could be problems such as children labeling each other. To avoid these problems, the groups are divided into schools. The three schools where the research will be conducted were determined by lot method. The first school formed the Kaledo game group, the second school the nutrition education group, and the third school the control group. BMI was determined by making anthropometric measurements of the children attending these schools. These students were stratified according to their overweight and obese status and gender. According to the power analysis, the minimum sample size for the experimental and control groups was calculated as 57 for each group. In this context, the sample size for each group was planned to consist of 64 people, taking into account incomplete and incorrect data and absenteeism. In this study population, students up to the sample size (n = 64) determined (32 overweight students and 32 obese students) by Power analysis for each school were determined by drawing of lots method. Later, the interventions defined in the groups were initiated.
