In this open-label, acute intervention study, we will recruit 120 sex-matched participants aged 20-70 years (100 normal or overweight/obese subjects and 20 Mets subjects). They will be assigned to one of the six groups according to age, BMI and with and without MetS and have a standardized mixed macronutrient tolerance test (MMTT) by orally administered a 400-ml beverage (75g glucose, 60g lipid, and 20g protein). Fasting and postprandial blood, and urine and fecal samples will be collected. The primary aim is to establish a more comprehensive system to quantify different aspects of metabolic health based on fasting and postprandial data. The study protocol has been approved by the Ethics Committee of Shanghai Institutes for Biological Sciences.

The recruited 120 subjects (60 men and 60 women aged 20-70 years) will be recruited according to the followings: 1) individuals aged 20-29 years with normal weight (18.5 kg/m2 ≤ BMI < 24 kg/m2); 2) individuals aged 30-49 years with normal weight; 3) individuals aged 30-49 years with overweight/obesity (BMI ≥ 24 kg/m2); 4) individuals aged 50-70 years with normal weight; 5) individuals aged 50-70 years with overweight/obesity; and 6) individuals aged 30-70 years with MetS. A standard questionnaire will be use to collect Information like lifestyle factors, nighttime sleep duration; anthropometric measurements will be performed. Blood samples will be collected via a catheter at fasting state (t = 0 min) and 5 successive time points post-MMTT (t = 30, 60, 120, 180 and 240 min). At t = 0 ,1 and 2 h, the fingertip blood will be collected as well. Body composition will be measured by dual energy x-ray absorptiometry (DXA). All these samples will be used to the assessment of blood chemistry, metabolomics, single nucleotide polymorphism (SNP), gut microbiota etc.

Inclusion Criteria:

• healthy subjects: age 20-70 BMI ≥ 18.5 kg/m2
• Mets subjects:

age 30-70 BMI ≥ 18.5 kg/m2 and at least meet three of the following criterions(NCEP-ATPIII, for Asian Americans)

1. Waist circumference ≥ 90 cm (men), ≥ 80 cm (women).
2. Total triglyceride ≥ 1.7 mmol/L.
3. HDL-c <1.03 mmol/L in men, <1.3 mmol/L in women.
4. Systolic blood pressure ≥ 130 mmHg or diastolic blood pressure ≥ 85 mmHg.
5. Fasting plasma glucose ≥ 5.6 mmol/L.

Exclusion Criteria:

1. clinically diagnosed diabetes or use of anti-diabetic medications;
2. clinically diagnosed cardiovascular, kidney, liver, pituitary, alimentary tract, and thyroid diseases, cancer(s), or mental illnesses;
3. pregnancy or lactation;
4. having gastrointestinal surgery within 1 year, excepting appendicitis or hernia;
5. current use of antidepressant(s);
6. alcohol consumption > 40 g/d or other substance abuse;
7. severe diarrhea (watery stools ≥ 3 times/day ≥ 3 days or longer) in previous 3 months;
8. participating any other studies within previous 3 months.