## 2 Materials and Methods  
The study was originally planned and approved to follow a controlled design with a randomized control group. However, due to the emergent COVID-19 situation, true randomization of the group assignments was not possible. Patients were assigned to either the intervention or the control group consecutively, the control group starting only after some months of delay, when the COVID-19 restrictions were lifted again. Based on previous studies on the primary outcome variable (weight loss or abdominal circumference), 116 patients' data were estimated to suffice for performing the statistical tests with 80% power. With a 10% drop-out rate, this required a total of 130 patients; i.e., 65 patients in the telemedicine group as well as in the control group. Both groups were educated for a lifestyle intervention at the start of the study. We used convenience sampling to recruit volunteers with MetS, defined by the presence of at least 3 ATP-III risk factors [1]. We included participants (men and women) aged between 25 and 70 years who practiced only very low level self-reported regular physical activity (less than 30 min a week). We did not include patients who were unable to give informed consent, had planned invasive cardiology procedures, had uncontrolled hypertension, Type 1 or Type 2 diabetes treated with more than one insulin dose per day, heart failure, renal impairment, tumor disease, severe cognitive dysfunction, or any known condition preventing physical exercise or seriously impairing the capacity to act. In the intervention group, patients took part in an individual dietetic consultation at the start of the trial in order to plan the dietetic intervention. The intervention adhered to the accepted principles of medical nutrition therapy [15; 16]. During the consultation, a detailed dietary history was taken with insights into patients' lifestyle, habits, dietary preferences, frequency and quantity of consumption of various food types, beverages, meal settings, timing, and other pertinent factors. Based on this information, the patients' nutritional plans were developed collaboratively including short-term as well as long-term goals. These goals were discussed during the follow-up consultations and modified as necessary. Long-term objectives included, for example, defining the extent of weight loss, while short-term goals entailed the implementation of specific daily tasks, such as increasing vegetable intake to half a plate or eliminating sugar from coffee. In general, the plans did not include any strict dietary restrictions. In the rest of the trial, volunteers lived their everyday life with telemedical support. For this they received a wireless body weight scale and a connected smart watch supporting automated exercise logging. They also received a smart phone with a pre-installed copy of a dietary logger and lifestyle app developed in a previous project [17]. Patients were instructed to weigh themselves every day and precisely log their daily meals on as many full days as possible. The app generates instant visual feedback on the energy nutrient contents (calorie, fat, carbohydrate, protein) of the logged item and its contribution to the daily totals, in comparison to the personalized recommended values. All logged and measured data were stored in a cloud database with web-based user interfaces for the supervising dietitians to track the recorded diet, exercise and weight values [18]. A weekly personal tele-consultation was scheduled when the patient could talk with the supervisor over results achieved (e.g., weight loss) and dietary changes (e.g., introduction of new vegetable-based foods), and they received advice on common situations (e.g., eating out, holidays, eating before/after exercise, shopping or cooking). In general, patients were regularly encouraged to practice self-care; e.g., packing healthy and easily transportable snacks to work.