2.3. Study Variables and Instruments
We assessed dietary intake in the NutriFast study using a food frequency questionnaire (FFQ) for the cluster analysis and 3-day food records for nutrient analysis. The FFQ queries the consumption frequency of certain spices and herbs at baseline and at weeks 6 and 12. Because of the scheduled counselling sessions based on the food records, these were collected at different times to the FFQ. Three 3-day food records were assessed for each patient at study week -1 (baseline) and at study weeks 4 and 9. Participants weighed and recorded all foods and beverages consumed using an electronic kitchen scale on three consecutive days (2 weekdays and one weekend day). When exact weighing was not possible—e.g., in the case of eating out—household measures (e.g., spoons, cups) and photos of the dish allowed semi-quantitative recording. A trained research team member coded food records according to a standardized data entry manual using the NutriGuideAbsolute dietary intakes were compared with the current dietary reference intake (DRI) published by the Societies for Nutrition in Germany (DGE), Austria (Österreichische Gesellschaft für Ernährung, ÖGE) and Switzerland (Schweizerische Gesellschaft für Ernährung, SGE), being the so-called D-A-CH (D—Deutschland, Germany, A—Austria, CH—Confoederatio Helvetica, Switzerland) recommendations [