Obesity, the prevalence of which is still on the rise, is related to the main chronic diseases affecting the health of the population. Therefore, in 2004, the World Health Assembly approved the Global Strategy on Diet, Physical Activity and Health with the aim of reducing the risk factors of nontransmittable diseases related to unhealthy diets and physical inactivity. Along this same line, the Spanish Ministry of Health and Consumer Affairs began implementing the NAOS Strategy in 2005 as a platform from which to include and promote all those initiatives contributing to achieving the necessary social change in the promotion of healthy eating and the prevention of a sedentary lifestyle by meeting certain specific challenges within different scopes of action. The NAOS Strategy extends far beyond the healthcare and educational areas, by combining actions in all those sectors of society playing a role in preventing obesity. Informative campaigns, agreements with public and private institutions, voluntary working agreements, educational programs and supporting health promotion initiatives are some of the activities being carried out as part of the NAOS Strategy. Carrying out these activities and incorporating yet others, in conjunction with the work of evaluating and monitoring all of these activities, will be what is going to make it possible to maintain a high degree of effectiveness in preventing obesity.