Time-Restricted eating may supercharge flu and COVID shots in seniors

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Male and female participants, enrolled in a 1:1 ratio * Age 60-85 years * Body mass index (BMI) 20-35 kg/m² * Capacity to give informed consent * Existing health insurance to allow evaluation and treatment of any incidental findings * Usual daily eating window \> 11 hours * First meal of the day before 10:00 AM * Willingness to receive seasonal influenza and COVID-19 vaccination and proof of scheduled appointment * Willingness and ability to follow a prescribed TRE dietary regimen (8-hour daily eating window; 16-hour fast without any caloric intake) * Appointment for simultaneous influenza and COVID-19 vaccination pre-arranged with primary care physician and coordinated with study team to align with TRE intervention Exclusion Criteria: * Any vaccination (especially influenza and/or COVID-19) within 6 months before the intervention start * Vaccinations not related to the study, administered during the study period from V0 to V4 * History of influenza infection within 6 months prior to initiation of the study intervention * History of severe adverse reactions to prior vaccinations * Use of pharmacological weight-loss agents (e.g., semaglutide) * Diabetes mellitus under ongoing pharmacological treatment * Symptoms of systemic inflammatory or autoimmune disease * Immunosuppression (including use of immunosuppressive drugs) * Severe hypertension (systolic \> 180 mmHg or diastolic \> 110 mmHg) * Diseases or functional disorders which, in the opinion of the study physician, preclude participation in the study * Participation in any fasting intervention (e.g., TRE, alternate-day fasting, 5:2, 18:6) within 6 months before enrollment * Participation in another diet or weight-loss program (e.g., intensive athletic training) * Night-shift or rotating-shift work * Severe, active, or unstable medical conditions requiring treatment * Postoperative recovery phase * Antibiotic therapy within 3 months before enrollment * Acute or chronic infections * Therapeutic or medically prescribed special diets * Vegan diet * Current smoker * Weight change \> 2 kg in the month before enrollment * Known substance, drug, or alcohol abuse * Anemia * Claustrophobia * Legal incapacity or any other circumstance that prevents full understanding of the nature, importance, and implications of the study