LDL (bad) and HDL (good) cholesterol influence heart risk. Major causes of high LDL include saturated/trans fats, obesity, inactivity, smoking, and genetics. Effective measures include switching fats to unsaturated oils, increasing soluble fiber and plant proteins, regular exercise, quitting smoking, and medical therapy such as statins when indicated.
How cholesterol works
Cholesterol travels in the blood attached to lipoproteins. Low-density lipoprotein (LDL) carries cholesterol to tissues and is often called "bad" cholesterol because excess LDL promotes plaque buildup in arteries. High-density lipoprotein (HDL) helps remove cholesterol from the bloodstream and transports it back to the liver for disposal.
Both LDL and HDL are produced by the body. Problems arise when LDL levels rise or HDL levels fall, increasing cardiovascular risk.
Common causes of high cholesterol
Diet high in saturated and trans fats. Foods rich in saturated fats (fatty meats, full-fat dairy, butter) and industrial trans fats raise LDL. Many countries have reduced or banned industrial trans fats, but processed foods can still contain them.
Excess calories and obesity. Carrying extra weight often raises LDL and triglycerides and lowers HDL.
Physical inactivity. Sedentary behavior typically lowers HDL and worsens other lipid measures.
Smoking and excess alcohol. Smoking harms blood vessels and lowers HDL. Heavy alcohol use increases triglycerides and may worsen overall lipid control.
Genetics and medical conditions. Familial hypercholesterolemia and other genetic disorders can cause very high LDL. Conditions such as diabetes, hypothyroidism, and certain medications can also raise cholesterol.
Age and sex. Cholesterol patterns change with age; after menopause, LDL often increases in women.
Evidence-based steps to reduce LDL and improve lipids
Diet adjustments. Replace saturated fats with unsaturated oils (olive, canola) and eat more vegetables, fruits, whole grains, and legumes. Soluble fiber from oats, beans, apples, and berries helps lower LDL. Nuts and plant sterols/stanols (available in some fortified foods) also reduce LDL modestly.
Eliminate trans fats. Read labels and avoid hydrogenated oils and many processed baked goods.
Choose healthier proteins. Swap fatty cuts of meat for lean poultry, fish, or plant proteins such as beans and tofu. Fatty fish two times a week supplies omega-3s that lower triglycerides.
Move regularly and lose weight when needed. Aerobic activity and modest weight loss raise HDL and lower LDL and triglycerides.
Quit smoking and limit alcohol. Stopping smoking improves HDL and vascular health. Keep alcohol consumption moderate or avoid it if advised by your clinician.
Medication when needed. Lifestyle changes help many people, but drugs - most commonly statins - remain the primary treatment for high LDL when risk is elevated. Talk to your healthcare provider about screening, risk assessment, and whether medication is appropriate.
Bottom line
High cholesterol usually results from a mix of diet, lifestyle, genetics, and other health conditions. Practical steps - healthier fats, more fiber, regular exercise, smoking cessation, and medical follow-up - can lower LDL and reduce cardiovascular risk.