Exploratory Study Therapeutic Fasting Reduce Physical Limitations, Quality of Life During Aromatase Inhibitor Therapy

After baseline (t0), all patients will receive the following intervention: 7 days of online supervised prolonged therapeutic fasting (max. 350 kcal/d). Following the study intervention, at t1, patients will be offered a for a potential effect as sustainable as possible in addition to a dietary change. According to the following criteria: * As plant-based as possible * Rich in nutritive prebiotics * In addition, this group should include intermittent fasting/time restricted eating (16/8h) into their dietary habits (at least 6d/week). All patients will be interviewed on a regular basis and anthropometric data will be collected accordingly at following time points: * t1 (at the end of the fasting intervention). * t2 (3 months after t0)