The goal of this observational cohort study is to delineate the five-year dynamic trajectories of metabolic phenotypes in Chinese adults with overweight or obesity, with or without type 2 diabetes, focusing on transition rates from metabolically healthy overweight/obesity to unhealthy overweight/obesity or to type 2 diabetes, as well as the incidence and progression of diabetic complications and cardiovascular events in those with type 2 diabetes and overweight/obesity. Researchers will compare three phenotype groups, namely metabolically healthy overweight/obesity, metabolically unhealthy overweight/obesity, and type 2 diabetes with overweight/obesity, to assess differences in metabolic parameter changes, complication rates, and cardiovascular risk. Participants will use a digital health management platform for data upload and lifestyle support, and will complete comprehensive health assessments at baseline, at 2.5 years, and at 5 years, along with annual light follow-ups.

Inclusion Criteria:

1. Able to understand and voluntarily sign the informed consent form, and willing to comply with all study requirements.
2. Age between 18 and 60 years (inclusive).
3. Meets at least one of the following overweight/obesity criteria: a) BMI ≥ 24 kg/m²; b) male waist circumference ≥ 90 cm, female waist circumference ≥ 85 cm.
4. Capable of basic smartphone operation and able to use WeChat or similar communication tools for daily communication.

Exclusion Criteria:

1. Diagnosis of type 1 diabetes, latent autoimmune diabetes in adults (LADA), maturity-onset diabetes of the young (MODY), or other specific types of diabetes.
2. Endocrine or metabolic diseases that may affect body weight, including untreated thyroid disorders (hyperthyroidism: TSH < 0.1 mIU/L with FT4 > upper normal limit; hypothyroidism: TSH > 10 mIU/L), Cushing syndrome, acromegaly, polycystic ovary syndrome, or hypopituitarism.
3. Severe liver disease (Child-Pugh class B or C).
4. Renal insufficiency (estimated glomerular filtration rate < 30 mL/min/1.73 m²).
5. Severe cardiac dysfunction (New York Heart Association class III or IV).
6. Major cardiovascular or cerebrovascular event within the past 3 months (acute coronary syndrome, stroke).
7. Uncontrolled hypertension (systolic blood pressure ≥ 180 mmHg or diastolic ≥ 110 mmHg) or uncontrolled diabetes (HbA1c ≥ 9.0%).
8. Active malignancy (diagnosed or treated within the last 3 years).
9. Inflammatory bowel disease or conditions causing malabsorption (Crohn disease, active ulcerative colitis, pancreatitis with steatorrhea).
10. Neuropsychiatric disorders (anorexia nervosa, bulimia nervosa, schizophrenia, major depression, or bipolar disorder).
11. Diseases or physical conditions that impair motor function (severe osteoarthritis, Parkinson disease, paralysis, or cardiopulmonary insufficiency).
12. Long-term use of antipsychotic drugs, systemic glucocorticoids, or other medications judged by the investigator to affect study outcomes.
13. Pregnancy or planned pregnancy during the study period.
14. History of or planned organ transplantation.
15. Inability to operate the AI-based system or comply with follow-up procedures.
16. Concurrent participation in another interventional clinical trial that may influence the results of this study.
17. Unwilling or unable to provide informed consent.

Chinese adults aged 18-60 years with overweight or obesity (BMI ≥ 24 kg/m² or central obesity: male waist circumference ≥ 90 cm, female ≥ 85 cm). Enrolled from 24 hospitals across China. Participants are classified into three groups: metabolically healthy overweight/obesity (MH-OW/OB), metabolically unhealthy overweight/obesity (MU-OW/OB), and type 2 diabetes with overweight/obesity (T2DM-OW/OB). All participants must be able to use a smartphone for daily communication and provide written informed consent. Key exclusions include type 1 diabetes, severe hepatic/renal impairment, uncontrolled hypertension or diabetes (HbA1c > 9.0%), active malignancy, pregnancy, and conditions interfering with follow-up or AI platform use.