The expected outcome of this study is that continuous 8-week supplementation with the PI-YSP-0111 prebiotic formulation will exert beneficial effects on gut microbiota modulation and liver health.

All participants will undergo blood, urine, and fecal sample collection at baseline and after 8 weeks of supplementation. Body composition measurements and questionnaire assessments will be conducted at baseline, after 4 weeks, and after 8 weeks of supplementation. The collected data will be analyzed using a two-way mixed-design analysis of variance (ANOVA) to compare both between-group and within-group differences.

Inclusion Criteria:

1. Healthy males or females aged 18 to 65 years.
2. BMI between 23.0 and 40.0 kg/m².
3. Waist circumference: ≥ 90 cm for males and ≥ 80 cm for females.
4. Participants are willing to maintain their usual dietary habits, daily routines, and physical activity levels during the study period, and have no plans to relocate.
5. Participants have fully understood the study procedures and have signed the informed consent form.

Exclusion Criteria:

1. Presence of gastrointestinal diseases, such as inflammatory bowel disease, irritable bowel syndrome, gastroesophageal reflux disease, Crohn's disease, or a history of bariatric surgery.
2. Recent history of acute gastroenteritis, constipation or diarrhea; psychiatric disorders (e.g., depression or schizophrenia); cardiovascular diseases (e.g., hypertension); known allergy or hypersensitivity to the investigational product; extreme dietary habits; significant body weight change (>4.5 kg) within the past three months; recent use of antibiotics or antifungal agents; or use of medications affecting gastrointestinal function (such as probiotics, laxatives, or nonsteroidal anti-inflammatory drugs [NSAIDs]).
3. Exposure to unapproved medications, alcohol abuse, or substance abuse.
4. Female-specific conditions, including significant gastrointestinal symptoms during menstruation, irregular menstrual cycles, pregnancy, planned pregnancy, or breastfeeding (participants who become pregnant during the study period will also be excluded).
5. Short-term use of corticosteroids, nonsteroidal anti-inflammatory drugs, immunosuppressive agents, interferons, or immunomodulatory agents within the past one month.
6. Use of any weight-loss medications (including oral agents, injections, or traditional Chinese medicine) within the past three months.
7. Participation in any other interventional clinical study within the past one month.
8. History of cancer or current malignancy within the past two years, except for non-melanoma skin cancer.
9. Occurrence of major trauma or any surgical procedures within the past one month.
10. History of diabetic ketoacidosis.