The aim of the present study was to investigate the effect of intervention with Lactobacillus paracasei K56 on body fat, metabolic risk markers,inflammatory markers and gut microbiota composition in obesity.

Recent data suggest that gut microbiota can function as an environmental factor that modulates the amount of body fat and obese individuals have an altered gut microbiota.The results of previous animal studies have suggest that a probiotic strain Lactobacillus paracasei K56 have reduced high-fat diet induced obesity.

In this randomised,double blind ,placebo controlled study, the participants were randomly assigned to probiotic K56 group or placebo group to evaluate the fat-reducing effect of the Lactobacillus paracasei K56 by continuously supplementing probiotic or placebo capsules.

Inclusion Criteria:

• Obesity : BMI>=30kg/m2,or percent body fat(PBF) >=25% for male, >=30% for female.

（Note: If PBF was eligible, it was recommended that 26 ≤ BMI ≤ 40）

• Age: 40 - 65 years old adults
• Who has the conditions to preserve the test samples at low temperature throughout the whole process

Exclusion Criteria:

• Patients with severe chronic diseases（heart, liver, kidney, hematopoietic system, tumor and other serious diseases, mental illness and organ surgery history, etc.) and complications;
• Patients with severe allergy and immunodeficiency;
• Patients with a clear history of gastrointestinal diseases (ulcer, irritable bowel syndrome, etc.);
• History of intervention with fat-reducing drugs or health products in the past 2 months
• Take weight control measures (diet, exercise, etc.) within the past month
• Participation in other clinical trials within the past 3 months
• who have used antibiotics in the past 2weeks ;
• Those who cannot guarantee to maintain their current lifestyle during the trial period
• Those who fail to consume the tested samples as required, or fail to follow up on time, resulting in failure to determine the efficacy