Clinical Research Directory

Inclusion Criteria: * Overweight and obese men and postmenopausal women between 45-70 years of age, BMI range of 25.0-39.9 kg/m2 and elevated LDL-C levels (130-189 mg/dL). Exclusion Criteria: * Adults unable to consent, individuals who are not yet adults (infants, children, teenagers), pregnant or lactating women, women planning to become pregnant in the next four months and prisoners will be specifically excluded. Additional exclusion criteria are listed below: * Allergy to walnuts or other nuts * Eating more than 25 grams of fiber per day, assessed by the Block Dietary-Fruit-Vegetable-Fiber Screener© * Taking medications or supplements known to affect metabolism or gut microbiota composition (i.e. Metformin, statins, antibiotics within the past 3 months, fiber supplements, probiotics, and others) * Documented chronic diseases including diabetes, renal or liver disease, metabolic syndrome, active cancer, MI or stroke, history of gastric bypass or GI disease (e.g. Crohn's Disease, Irritable Bowel Disease, diverticulosis, diverticulitis, etc.) * Smoker or living with a smoker, including vaporizer and/or electronic cigarettes. * Illicit drug use, cannabis usage, or consuming \>1 alcoholic drink/day * Extreme dietary or exercise patterns * Recent weight fluctuations (\>10% in the last 6 months) * Taking prescription lipid medications or supplements that may affect lipoprotein metabolism (i.e. \>1 g of fish oil/day, antioxidant supplements) * Taking exogenous hormones * Poor venous access * Unwillingness to comply with study protocols