Integrating Metabolic and Vascular Sensors to Monitor Cardiometabolic Disorders After Nutrition Interventions

The investigators will conduct a randomized, controlled crossover intervention study. The investigators will enroll 54 participants, aged >18 years, BMI >25 kg/m2 with metabolic syndrome. During the first phase, all participants will consume their habitual diet for 2 weeks to establish baseline. Then participants will be randomized to either a Mediterranean diet (MED), high-fat/low carb diet (HF/LC), or low-fat diet (LF) for 14 days with 2 weeks washout between the different diets. The wearable system will monitor basal levels and the changes for glucose, cholesterol, TG, and NO through sweat analysis and HR, HRV, and PWV for carotid arterial stiffness during each diet intervention.

• Mediterranean diet (MED), high-fat/low carb diet (HF/LC), and low-fat diet (LF) (Dietary supplement): Participants will be randomized to either Mediterranean diet (MED), high-fat/low carb diet (HF/LC), or low-fat diet (LF).
• The integrated sweat sensor and vascular sensor (wearable) (Device): The integrated sweat sensor and vascular sensor will be worn of each diet period.
• continuous glucose monitor (CGM) (Device): A continuous glucose monitor (CGM) will be placed on the patients during each diet period.

Primary outcomes

• Concentration of glucose [From enrollment to the end of measurement at 12 weeks]: The concentration of glucose (mg/dL) will be measured during each visit, across the different diets, to evaluate changes in metabolism
• Concentration of cholesterol [From enrollment to the end of measurement at 12 weeks]: The concentration of cholesterol (mg/dL) will be measured during each visit, across the different diets, to evaluate changes in metabolism.
• Concentration of triacylglycerol (TG) [From enrollment to the end of measurement at 12 weeks]]: The concentration of triacylglycerol (TG) (mg/dL) will be measured during each visit, across the different diets, to evaluate changes in metabolism.
• Concentration of Nitric oxide (NO) [From enrollment to the end of measurement at 12 weeks]: The concentration of Nitric oxide (NO) (ppm) will be measured during each visit, across the different diets, to evaluate changes in metabolism.
• Measurement of heart rate (HR) [From enrollment to the end of measurement at 12 weeks]: The heart rate (HR) (bpm) will be measured during each visit, across the different diets, to evaluate changes in vessel stiffness indirectly.
• Measurement of heart rate variability (HRV) [From enrollment to the end of measurement at 12 weeks]: The heart rate variability (HRV) (ms) will be measured during each visit, across the different diets, to evaluate changes in vessel stiffness indirectly.
• Measurement of pulse wave velocity (PWV) [From enrollment to the end of measurement at 12 weeks]: The pulse wave velocity (PWV) (m/s) will be measured during each visit, across the different diets, to evaluate changes in vessel stiffness.
• Body weight [From enrollment to the end of measurement at 12 weeks]: The body weight (BW) (kg) will be measured during each visit, across the different diets, to evaluate changes of BMI.
• Height [From enrollment to the end of measurement at 12 weeks]: The height (m) will be measured during each visit, across the different diets, to evaluate changes in BMI.

Secondary outcomes

• BMI [From enrollment to the end of measurement at 12 weeks]: The Body mass index (BMI) (kg/m2) will be measured during each visit, across the different diets, to evaluate changes of body fat.

Sex: All, ages: 18 Years to 55 Years, accepts healthy volunteers

Inclusion Criteria:

* United States Veterans
* Male or female, age 18-55 years at the time of signing informed consent.
* at least 2 of the following: waist circumference > 40" for men and 35" for women, FBS >100 mg/dl, triglycerides > 150 but < 500 mg/dL, HDL < 40 mg/dL, Pre- hypertension or hypertension (BP>120/80 mmHg but <150/90 mmHg)

Exclusion Criteria:

* History of diabetes require medications
* History of alcohol intake ≥ 20g/day
* History of cirrhosis
* Renal impairment measured as estimated Glomerular Filtration Rate (eGFR) value of <30 mL/min/1.73 m2
* History of thyroid disease, but not taking medication or medication dosage changed one or more times over last 6 months. History of thyroid disease and on a stable dose of prescription medication for 6 months or longer is acceptable.
* Any unstable medical conditions or terminal diagnosis.
* Any participant who is unwilling to sign an informed consent form will not be admitted into the study.

• Tzung Hsiai, M.D., Ph.D., Principal investigator, VAGLAHS and UCLA