I recommend to read the following paper: da Costa FF, Schmoelez CP, Davies VF, Di Pietro PF, Kupek E, Assis MAA. Assessment of Diet and Physical Activity of Brazilian Schoolchildren: Usability Testing of a Web-Based Questionnaire. JMIR Research Protocols 2013;2(2):e31.
The paper shows a detailed presentation about Web-CAAFE. If you need, ask me more about the software. My best regards.