Obesity and overweight prevalence is increasing rapidly in Latin America. This increase has been attributed to lifestyle changes occurring in recent decades related to rapid socioeconomic development, including a more Westernized diet, physical inactivity, urbanization, rural-urban migration and some maternal-fetal factors. In addition, genetic factors may have a role, inducing a higher predisposition to accumulate abdominal fat and develop metabolic syndrome. This increase in obesity and metabolic syndrome is leading to higher morbidity and mortality due to Type 2 diabetes and cardiovascular disease. In a few poor countries, obesity coexists with undernutrition, making the situation even more difficult. Global intervention, from both governments and nongovernmental organizations, is necessary. They must play an active role, monitoring the food market and facilitating community-based initiatives that promote a healthy lifestyle. © 2009 Expert Reviews Ltd.