High Cholesterol: Causes Make an Appointment Refer a Patient Ask a Question Reviewed by Howard D. Weinberger, MD, FACC (July 01, 2019) A high level of cholesterol in the blood is due to abnormal levels of lipoproteins, the particles that carry cholesterol in the bloodstream. What causes high cholesterol? High cholesterol may be related to: Diet (eating a diet high in carbohydrates and fatty foods, and animal products) Weight (being overweight or obese) Lack of physical activity or sedentary lifestyle Genetic factors (having a family history of high cholesterol) Presence of other diseases (diabetes, underactive thyroid, etc.) It is important to note that a healthy lifestyle with moderate physical activity 30 minutes a day combined with a mostly plant-based diet is probably the best, no-cost, and most highly effective option as a first step toward improved cholesterol levels. High Cholesterol: Types High Cholesterol: Diagnosis Clinical Trials For more than 100 years, National Jewish Health has been committed to finding new treatments and cures for diseases. Search our clinical trials.