RESUMEN
We describe the magnitude and trends of obesity in Spain and of its main determinants, associated both with the increase in energy intake and the reduction of energy expenditure. Such determinants include factors from the individual subjects and from their environment. We also present the main features of the strategy for the Nutrition, Physical Activity, and the Prevention of Obesity, fostered by the Ministry of Health, as well as plans and activities carried out by the Regional Governments, to control this health disorder. We conclude that effective and sustained implementation of these activities is badly needed. It should be made along with the monitoring of obesity and its determinants in the general population. Research in this field should also be strengthened because social determinants of obesity are not known in depth, and the effectiveness of many of the interventions proposed by the national and regional initiatives is not well established yet. Moreover, in the next future, the effectiveness of intervention models applied to control the smoking epidemic must be assessed to examine its usefulness in the control of obesity. An example of this type of interventions is the limitation of the publicity of nutrient-poor and energy-dense foods addressed to children.