Obesity prevention in youth is a health priority, and teaching healthy habits toward this end is one of a school nurse's many responsibilities. A school nurse developed and implemented a school-wide, 2-week-long Activity and Nutrition Challenge (ANC) using the evidence-based 5-2-1-0 initiative to prevent and fight childhood obesity. Despite minimal promotion, nearly half of the students at two elementary schools participated and earned points by following the guidelines in the ANC. The amount of chocolate milk consumed by students dropped significantly during the ANC, showing that the healthy behavior of choosing beverages without added sugar had been positively impacted. Anecdotal evidence suggested positive changes in other healthy behaviors as well. This ANC was a new way for a school nurse to teach healthy habits to a large group of children in a short period of time, with limited extra work, and with promising results.