The present research started from the theme that currently involves the world population, especially children from different regions: overweight and obesity. This issue was addressed with special focus on children of the Social Institution Projeto Caminhando Juntos (CAJUN) that indicate overweight and obesity with high Body Mass Index (BMI). Starting from the principle that environments, technology, food and the reduction in the practice of physical activities are typical of the generation of the 21st century, a research on the possible causes of overweight and obesity in children associated to these factors was carried out. Thus, the analysis was made with children who attend the Projeto Caminhando Juntos Social Institution (CAJUN), in the Bonfim neighborhood in Vitória/ES, in order to investigate the possible causes of weight gain and its impacts on health and on the performance of daily activities. For data collection, the following instruments were used: collection of anthropometric measurements of the children, interviews with family members and bibliographic survey.