The study attempts to conduct randomized double-blind controlled trials to understand whether daily exposure to microplastics (MPs) can cause potential impacts on human health, explore whether the intake of Lactiplantibacillus plantarum PD01 can alleviate potential obesity-related damages caused by MPs, and provide a scientific basis for the prevention and nutritional intervention of health hazards caused by MP exposure.

Inclusion Criteria:

• Age 18-65 years.
• Body Mass Index (BMI) ≥ 24.0 kg/m² or meeting the criteria for central obesity (waist circumference ≥ 90 cm for men, ≥ 85 cm for women); participants with mild abnormalities in blood lipids and liver function indicators will be prioritized.
• Permanent residents of the local area during the trial period, with no plans for long-term business trips or travel.
• Fully understand the research content and voluntarily sign the informed consent form.

Exclusion Criteria:

• Diagnosed congenital or acquired immunodeficiency diseases, severe allergic diseases, active gastrointestinal diseases, and other acute or chronic diseases requiring long-term treatment.
• Use of antibiotics, immunosuppressants, probiotics, prebiotics, synbiotics, or other drugs that clearly affect gut microbiota or gastrointestinal function within the 6 months prior to the trial.
• Regular intake of nutritional supplements (such as vitamins, fish oil, etc.) within the 6 months prior to the trial.
• Having bad lifestyle habits such as smoking or alcoholism.
• Women who are pregnant, lactating, or planning to become pregnant.
• Weight change exceeding 5% of body weight within the 3 months prior to the trial.
• Participation in or planning to participate in any other clinical intervention studies.

The on-site implementation personnel and those responsible for coordinating the study only received the study number of the subjects, and were unaware of the intervention group allocation of the subjects. The subjects were also unaware of their intervention allocation. A copy of the sealed envelope of the non blinded study number for each subject is provided only to the study supervisor. Before the completion of data collection, the investigators and researchers kept the blind method for treatment allocation. All subjects were monitored in a double-blind way throughout the study period, and the subjects could not distinguish their own grouping by asking questions or from appearance and texture.