Purpose - This exploratory study compares knowledge about dietary fats in some dairy products and other foods across consumers from France, (French-speaking) Canada and the U.S. A relation is explored between the types of information, knowledge levels and obesity predominance. Design/methodology/approach - A nine-question nutritional test was developed and administered to three samples of consumers, respectively in Grenoble (France), Quebec, Canada and Ithaca, New York. In France, Canada and the U.S. the number of participants was respectively 100, 107 and 120. Participants were recruited randomly outside groceries stores and the test was administered directly through one-on-one interviews. Findings - Results indicate a significant gap in knowledge between consumers from the three countries studied. The level and quality of knowledge seems to be correlated with the nature of the informational background: A wider availability of information such as nutrition facts and public health recommendations on fat consumption seems to have a positive effect on the general level of knowledge. However, «technical» knowledge seems to be inversely correlated to the level of obesity.