The goal of this interventional study is to investigate how vegan diet affects health in healthy volunteers, Men and women ages 20 - 30 years old. The main questions it aims to answer are:

Change in Microbial community composition and metabolic alterations Changes in plasma metabolic profile. Researchers will compare changes in microbiota and plasma metabolites profile to see the influence of vegan diet in health. In the dietary trial, participants were first assigned to a 2-week omnivorous diet phase, then switched to a 2-week vegetarian diet phase

Inclusion Criteria: healthe Participants, ages 20-30 years old

Exclusion Criteria:

1. Oral antibiotic use or acute/chronic inflammation within the past 3 months;
2. Hormone intake within the past 3 months;
3. Use of any known interfering medications (e.g., insulin, glibenclamide, indomethacin, phentolamine, furosemide, phenytoin sodium, cortisone, etc.) or probiotics within the past month that may affect glucose or lipid metabolism;
4. Smoking or alcohol consumption;
5. Uncontrolled mental disorders (including a history of psychiatric hospitalization);
6. Currently participating in a weight loss or weight management program;
7. Following a special or medically prescribed diet (e.g., for celiac disease);
8. Comorbid cardiac or renal insufficiency;
9. Chronic constipation;
10. Hypertension;
11. Diabetes mellitus.