Movement has evolved to become one of the basic human needs, however today movement has become an action that few people perform as much as necessary. A person's basic motor skills, his growth and development depend on physical activity, which should begin in various forms from an early age. Lack of physical activity in childhood leads to delayed growth and development and later increases the risk of developing various diseases such as osteoporosis, cancer and obesity. In the past, children were more active, they spent more time outdoors, and today children move less and children's play often includes playing in front of screens, which means that children sit even while they are playing games. With the reduced number of children who are physically active, the number of obese children of early and preschool age is increasing. In this paper I will try to explain the impact of physical activity on children of early and preschool age and in what ways different organizational forms of physical activity can be implemented in kindergarten. I will refer to the influence of parents and their level of physical activity, which greatly affects the level of physical activity of children. I will explain what obesity is, how it is measured, what the symptoms and causes of obesity are, how obesity is treated and how to act to prevent childhood obesity. The best way to fight childhood obesity is prevention. Parents should choose healthy foods for their children from an early age, which they should prepare in a healthy way. The diet should be balanced, and the amount of water that the child should drink should not be neglected. In order for physical activity to become a child's habit, parents need to show them by example what it means to be physically active.