The lesson centers on the story of “Pizu,” a character who learns the importance of healthy eating and exercise after realizing the negative effects of consuming too much unhealthy food. Throughout the narrative, children are encouraged to make healthier lifestyle choices by observing Pizu’s journey of transformation, which includes walking more and eating nutritious meals like vegetable soup. The lesson highlights themes of friendship, support, and making sacrifices for better health, reinforcing positive habits in children.