The investigators will try to evaluate the effects of substitution of dietary animal protein by black soybean milk (400 mL x 2) per day on anthropocentric and metabolic parameters in obese subjects.

According to the survey by the Ministry of Health and Welfare, the proportion of obese male adolescents in Taiwan has been increasing year by year. Obesity is associated with chronic low-grade inflammation. Obese people prefer to intake foods containing higher levels of advanced glycation end products (AGEs). High intake of dietary AGEs (dAGEs) results in abdominal obesity, and shows positive correlation with body mass index (BMI) and waist circumference. When a large amount of AGEs accumulates in the body, inflammation usually occurs. Therefore, reducing dAGEs intake prevents the incidence of obesity, chronic diseases and aging. Black beans are high in protein. The black bean coats contain high level of anthocyanins. Previous studies demonstrated the biological functions of anthocyanins on blood lipid regulation, inflammation, and also inhibition of AGEs formation. Compared with meat (beef, pork, lamb, chicken, and seafood), the plant protein source, soy milk, under the same protein content showed significantly lower dAGE. In this study, the investigators will try to eveluate the effects of substitution of dietary animal protein by black soybean milk (400 mL x 2) per day on anthropocentric and metabolic parameters in obese subjects. This will be a randomized crossover interventional trial for 16 weeks: 0 to 4 weeks will be run-in period, 4 to 8 weeks and 12 to 16 weeks will be the soy milk or meat intervention period, and the between of two interventions (8 to 12 weeks) will be washout period. The body composition, blood pressure and AGE level will be measured. The blood, urine and feces sample will be collected for biochemical analysis and gut microbiome. The investigators expect the results could support the promotion of plant protein as part of dietary protein source to improve abnormal anthropometric and metabolic parameters in obese subjects.

Inclusion Criteria:

• 20 to 64 year male or female
• 27 <= BMI < 35 or waist circumference male >= 90 cm/female >= 80 cm
• fasting blood glucose: 100-125 mg/dL

Exclusion Criteria:

• Hypertension, cardiovascular disease, endocrine disease, acute and chronic liver and kidney disease, mental disease, binge or anorexia, or long-term drug use
• Consume probiotics, prebiotics, antibiotics or weight loss drugs regularly for the past month
• Try to lose weight and do resistance exercise regularly for the past month
• Allergic to soy products

IPD will be published in journals