The aim of this study is to develop a web-based food frequency questionnaire (eFFQ-CH), using the menuCH photo book and the framework of a food frequency questionnaire developed at ZHAW Wädenswil (the ZHAW FFQ). The development work will follow a unique approach based on the results of the menuCH Survey, the first national, representative nutritional data of the Swiss population. The project will deliver a web-based dietary assessment tool for an adult population in Switzerland with advantages over other existing tools.Following a multi-stage approach, we first aim to use menuCH results to guide the development of the new composite FFQ (BLV photo book and parts of the ZHAW FFQ). In this process, we will also consider suggestions from experts in other language-regions in Switzerland. Using these inputs, the FFQ will be optimized for structure, food items, photographs and other aspects of respondent usability (e.g. compliance). The tool will be implemented into a state-of-art content management platform, offering many advantages for research applications (including FAIR data principles). A validation study will be conducted, by testing the tool against the validated ZHAW FFQ and also studying reproducibility. Results will be summarized, and used to make final adjustments.