A massive open online course (MOOC) is an online course aimed at unlimited participation and open access via the Web. To assess the MOOC experience for teaching nutrition, healthy food consumption, physical activity and health promotion to prevent obesity. Two MOOC courses, (one with two versions), are described with the registration and evaluation instruments such as surveys carried out at the beginning and at the end of the courses. Effective participants in the three versions were 17.456, 11.121 in MOOC1, 2.351 in MOOC1 second version and 3.984 in MOOC2. Their median age was 31 years, 82% were women, 60% were professionals and 12% were foreigners. In the final evaluation of the three courses, 85% to 99% qualified as “very good” or “good” all the surveyed topics. Thirty five percent of participants reported having lack of time, 11% reported problems with internet connectivity and 3.9%, personal or work problems. This is the first experience with MOOC in health and nutrition to prevent obesity in Chile. Considering the good results and positive evaluation of these courses, we estimate that they are an important tool to prevent obesity and chronic diseases in Chile, Latin America and other regions of the world.