Obesity is associated with alterations in the perception and interpretation of internal bodily signals (interoception), which may influence eating behaviors, emotional regulation, and long-term weight outcomes. Bariatric surgery induces profound physiological and neurohormonal changes that may affect interoceptive awareness and illness perception, potentially impacting the risk of disordered eating behaviors after surgery.

This observational study aims to evaluate longitudinal changes in interoceptive awareness and illness perception in adults with severe obesity undergoing bariatric surgery, from the pre-operative phase to long-term follow-up. The study also explores the relationship between these psychological constructs and clinical and behavioral outcomes over time.

Interoception refers to the ability to perceive, interpret, and integrate internal bodily signals and plays a key role in appetite regulation, emotional processing, and eating behavior. Altered interoceptive processing has been associated with obesity, disordered eating behaviors, and psychological distress. In individuals with severe obesity, bariatric surgery represents the most effective treatment for weight reduction; however, the persistence or recurrence of maladaptive eating behaviors after surgery remains a relevant clinical concern.

Bariatric surgery leads to marked modifications in the gut-brain axis, neuroendocrine signaling, and central processing of internal bodily signals. These changes may influence interoceptive awareness and illness perception, which in turn could affect long-term behavioral, psychological, and clinical outcomes. Despite increasing interest in these mechanisms, longitudinal evidence on subjective interoceptive changes and illness perception before and after bariatric surgery remains limited.

This monocentric, longitudinal, ambispective observational study is conducted in adults with severe obesity evaluated for bariatric surgery at a tertiary referral center. Psychological and clinical data are collected during the pre-operative assessment and during post-surgical follow-up, allowing the evaluation of changes over time in interoceptive awareness, illness perception, psychological functioning, and weight-related outcomes.

The study includes both a retrospective component, based on existing clinical data, and a prospective component with repeated assessments over long-term follow-up. By characterizing trajectories of interoceptive awareness and illness perception before and after bariatric surgery, this study aims to improve the understanding of psychological and behavioral factors involved in post-surgical outcomes and to support the development of more personalized multidisciplinary care pathways for patients with severe obesity.

Inclusion Criteria:

• Adults aged 18 years or older.
• Diagnosis of severe or morbid obesity (body mass index ≥35 kg/m² with obesity-related comorbidities or ≥40 kg/m²).
• Undergoing multidisciplinary evaluation with indication for bariatric surgery.
• Ability to provide informed consent and complete self-administered questionnaires.

Exclusion Criteria:

• Age younger than 18 years.
• Presence of neurological disorders associated with cognitive impairment that may interfere with questionnaire completion.
• Pregnancy or breastfeeding at the time of enrollment.
• Inability to complete study assessments due to language barriers or other conditions limiting participation.

The study population consists of adults with severe or morbid obesity undergoing pre-operative multidisciplinary evaluation for bariatric surgery at a tertiary referral center. Participants are assessed before surgery and during post-surgical follow-up as part of routine clinical care.