The objective of our study was to evaluate the association between consumption of food during the journey from home to school and back, with overweight and obesity, in a nationwide representative sample of school children. We assessed consumption outside the home in 9537 children, with information on availability and consumption of selected groups of food and beverages. Height, weight, total energy consumption, and sociodemographic variables were also obtained. We developed logistic regression models, and tested interactions with sociodemographic variables. The results of our study show that the prevalence of overweight and obesity was positively associated with dairy consumption in girls (OR:1.70; p = 0.01), as well as fried snacks consumption in school children living in Mexico City (OR: 1.68; p = 0.06). Consumption of fruits and vegetables in medium and high socioeconomic levels was negatively associated with the prevalence of overweight and obesity (OR: 0.54; p = 0.01 and 0.59; p = 0.07, respectively). We concluded that children during their stay away from home have a high availability of energy dense foods, which can influence their consumption and contribute to the development of overweight and obesity, so it is important to investigate this association in prospective studies.