Understanding How Gut and Brain Barriers Are Linked to Inflammation in Obesity

The goal of this observational study is to understand how obesity affects the function of the gut and blood-brain barriers in adults. These barriers protect the body and brain from harmful substances, and changes in their function may lead to inflammation and increased risk of chronic diseases. The study will include 25 participants with obesity (BMI over 35) and 25 healthy participants (BMI 20-25) matched by age and gender. The main questions it aims to answer are: * How does obesity affect the blood-brain barrier and its connection to cognitive and psychopathological status? * Does increased gut permeability lead to higher inflammation levels? * Does obesity increase the permeability of the gut barrier? Researchers will compare results from participants with obesity to healthy participants to determine how obesity impacts barrier function, inflammation, and overall health. Participants will: Attend three visits over several days, including: * Screening visit: A health examination with weight, height, blood pressure, blood tests, and a scan to assess body fat distribution. * Visit 1: Provide a stool sample, drink a sugar solution to assess gut permeability, collect urine samples, and take cognitive as well as psychopathological tests. * Visit 2: Undergo an MRI scan to assess the blood-brain barrier and its function. The study aims to identify how obesity-related changes in these barriers contribute to health risks.