The goal of this observational study is to evaluate the impact of overweight, obesity, and lifestyle changes on work performance, work ability, quality of life, and overall well-being in medical residents working in hospital and university settings. The main questions it aims to answer are:

• Is overweight and obesity associated with reduced work productivity, including absenteeism, presenteeism, and perceived work ability?
• Is overweight and obesity associated with lower health-related quality of life, psychological well-being, and worker well-being?
• Do lifestyle improvements and clinically significant weight loss over a 12-month period lead to measurable improvements in work productivity, work ability, quality of life, and well-being?
• Do changes in physical health, mental health, and organizational factors mediate the relationship between weight loss and occupational outcomes? Participants will undergo assessments at baseline and after 12 months of follow-up. Researchers will evaluate associations between body weight status, health outcomes, and occupational performance over time.

Participants will: Attend occupational health surveillance visits at baseline and at 12 months. Undergo anthropometric measurements, including body mass index (BMI), waist circumference, and blood pressure assessment.

Provide blood samples for routine laboratory evaluation, including metabolic, cardiovascular, inflammatory, and hematological parameters.

Complete validated questionnaires assessing health-related quality of life (SF-12), work ability (Work Ability Index), work productivity and activity impairment (WPAI), fatigue (Fatigue Severity Scale), psychological well-being (PGWBI), mental health (DASS-21), worker well-being (NIOSH WellBQ), and resilience (CD-RISC). Provide information on sociodemographic characteristics, lifestyle habits, medical history, occupational characteristics, and work-related exposures.

The study will estimate the prevalence of overweight and obesity in a cohort of medical residents and investigate their association with occupational and health-related outcomes. Longitudinal analyses will examine whether changes in lifestyle behaviors and body weight are associated with changes in productivity, absenteeism, presenteeism, work ability, quality of life, and well-being over a 12-month observation period. The study will also explore potential mechanisms linking weight status and occupational outcomes, including physical health, psychological health, and organizational factors.

Inclusion Criteria:

• Male and female medical residents (physicians in specialty training).
• Actively working in hospital or university healthcare settings at the time of enrollment.
• Willing and able to participate in baseline and 12-month follow-up assessments.
• Provision of written informed consent for study participation and processing of personal data.

Exclusion Criteria:

• Pregnancy at baseline or occurring during the follow-up period.
• Presence of severe clinical conditions that significantly impair work ability or performance, including active cancer treatment, unstable cardiovascular disease, major neurological disorders, or diabetes mellitus.
• Inability or unwillingness to complete study assessments.
• Refusal or withdrawal of informed consent.

The study population consists of male and female medical residents (physicians in specialty training) actively working in hospital and university healthcare settings and undergoing routine occupational health surveillance at the Occupational Medicine Unit, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy. Participants will be evaluated for body weight status, lifestyle factors, quality of life, psychological well-being, work ability, and work productivity at baseline and after 12 months of follow-up.