Several things raise your cholesterol, and diet is only part of the picture. Your genetics, activity level, hormones, certain medications, and underlying health conditions all play a role. Understanding which factors apply to you is the first step toward getting your numbers into a healthy range: below 200 mg/dL for total cholesterol and below 100 mg/dL for LDL, the type most linked to heart disease.
Saturated Fat and How It Works
Saturated fat is the single most well-established dietary driver of high LDL cholesterol. It’s concentrated in red meat, butter, cheese, full-fat dairy, and coconut oil. The current dietary guidelines recommend keeping saturated fat below 10% of your daily calories, which works out to roughly 22 grams on a 2,000-calorie diet.
The mechanism is straightforward. Your liver is responsible for pulling LDL particles out of your bloodstream using specialized receptors on its surface. Saturated fats with 12 to 16 carbon atoms (the types found in meat, dairy, and tropical oils) reduce the number of those receptors. With fewer receptors working, your liver clears less LDL from the blood, and levels rise. Research in animal models has confirmed that reduced liver clearance, not increased production, is the main way saturated fat raises LDL. Dietary cholesterol itself (from egg yolks, shellfish, organ meats) has a smaller effect for most people, but it contributes to the same problem by further suppressing those liver receptors.
Sugar and Refined Carbohydrates
High sugar intake raises cholesterol through a different pathway than fat does. Fructose, which makes up half of table sugar and most of high-fructose corn syrup, is processed almost entirely by the liver. Unlike glucose, fructose bypasses the liver’s normal rate-limiting step for energy metabolism, flooding it with raw materials for fat production. This process, called de novo lipogenesis, ramps up the liver’s output of triglyceride-rich particles called VLDL, which eventually become LDL particles in your bloodstream.
Fructose also activates fat-production genes in the liver independently of insulin, which means even moderate amounts can shift your lipid profile. The result is higher triglycerides and more circulating LDL. Sweetened beverages, candy, baked goods, and processed foods with added sugars are the biggest contributors. Whole fruit contains fructose too, but the fiber slows absorption enough that the liver isn’t overwhelmed in the same way.
Trans Fats
Trans fats are the worst type of fat for cholesterol because they raise LDL and lower HDL (the protective type) at the same time. Although artificial trans fats have been largely removed from the food supply, small amounts still appear in some fried foods, microwave popcorn, and imported packaged goods. Even naturally occurring trans fats in meat and dairy have a mild effect. If you see “partially hydrogenated oil” on an ingredient list, the product contains trans fat regardless of what the nutrition label says (manufacturers can round down to zero if a serving contains less than 0.5 grams).
Physical Inactivity
Sitting for long stretches raises your LDL, total cholesterol, and triglycerides. Studies tracking healthy adults have found a direct positive association between sedentary time (especially screen time) and unfavorable lipid levels. The flip side is equally clear: moderate-to-vigorous physical activity is consistently linked to higher HDL cholesterol, even after adjusting for diet, smoking, and demographics.
Exercise doesn’t just burn calories. It increases the activity of enzymes in your muscles and blood vessels that break down triglyceride-rich particles, freeing up components that get recycled into HDL. You don’t need extreme workouts. Brisk walking, cycling, swimming, or any activity that gets your heart rate up for 30 minutes most days is enough to shift your lipid profile in a measurable way. Reducing total sitting time matters independently of exercise, so breaking up long sedentary periods helps too.
Genetics and Family History
Some people do everything right and still have high cholesterol. The most common genetic cause is familial hypercholesterolemia (FH), which affects about 1 in 250 people. That’s far more common than the old estimate of 1 in 500, and most people with FH don’t know they have it.
FH is caused by mutations in genes that control how your liver clears LDL from the blood. Over 80% of cases involve a mutation in the LDL receptor gene itself, meaning the liver simply has fewer working receptors to pull LDL out of circulation. Another 5 to 10% involve a mutation in the protein that LDL uses to dock with those receptors. A small fraction involve a gene that causes the liver to destroy its own LDL receptors too aggressively.
If one parent passes on the mutation, LDL levels typically run in the 190 to 300+ mg/dL range from childhood onward. If both parents pass it on (extremely rare, about 1 in 300,000), LDL can exceed 500 mg/dL. A clue that FH runs in your family: a parent or sibling who had a heart attack before age 55 (men) or 65 (women), or cholesterol levels that stay stubbornly high despite a healthy diet.
Hormonal Changes
Estrogen helps the liver maintain its LDL receptors and supports healthy cholesterol clearance. When estrogen levels drop during menopause, total cholesterol, LDL, VLDL, and triglycerides all tend to rise. Research has found a significant negative correlation between estradiol levels and triglycerides in menopausal women, meaning the lower the estrogen, the higher the triglycerides. This is one reason women’s heart disease risk climbs sharply after menopause, even if their cholesterol was normal for decades before.
Hypothyroidism
An underactive thyroid is one of the most common medical causes of high cholesterol, and it’s frequently overlooked. Thyroid hormones play a direct role in how your liver handles cholesterol in at least three ways. First, they help maintain the number of LDL receptors on liver cells. When thyroid hormones drop, fewer receptors are produced, and LDL clearance slows. Second, thyroid hormones normally suppress a protein that destroys LDL receptors. In hypothyroidism, that protein goes unchecked, further reducing the liver’s ability to pull LDL from the blood. Third, thyroid hormones stimulate the conversion of cholesterol into bile acids, which is one of the body’s main routes for getting rid of excess cholesterol. When this process slows down, cholesterol accumulates.
The net effect is that both decreased thyroid hormone and the elevated TSH that accompanies it push LDL levels higher through overlapping mechanisms. If your cholesterol is newly elevated and you’re also experiencing fatigue, weight gain, cold sensitivity, or dry skin, a simple thyroid blood test can rule this out. Treating the thyroid problem often brings cholesterol back down without any other intervention.
Medications That Raise Cholesterol
Several widely prescribed drug classes can push your lipid numbers up as a side effect. This doesn’t necessarily mean you should stop taking them, but it’s worth knowing so you can monitor your levels and discuss the tradeoff with your prescriber.
- Beta-blockers: Commonly used for high blood pressure and heart conditions, these can raise triglycerides by 10 to 40% and lower HDL by 5 to 20%.
- Thiazide diuretics: Another blood pressure medication class that can increase total cholesterol, LDL, and triglycerides, particularly at higher doses.
- Corticosteroids: Used for inflammation and autoimmune conditions, high doses tend to raise triglycerides and LDL by boosting the liver’s fat production.
- Atypical antipsychotics: These medications are associated with metabolic side effects, primarily increased triglycerides.
- Retinoids: Oral acne medications in this class are known to cause significant triglyceride elevations along with increases in LDL and total cholesterol.
- Anabolic steroids: These can reduce HDL by 20 to 70% while raising LDL, creating a particularly unfavorable ratio.
- Immunosuppressants: Certain drugs used after organ transplants or for autoimmune diseases raise total cholesterol, LDL, and triglycerides.
Other Contributing Factors
Excess body weight, particularly visceral fat stored around your midsection, increases the liver’s production of VLDL particles and raises triglycerides. Losing even 5 to 10% of body weight can measurably improve your lipid profile. Smoking doesn’t directly raise LDL, but it lowers HDL and damages blood vessel walls, making whatever LDL you do have more dangerous. Heavy alcohol intake raises triglycerides, while the relationship between moderate drinking and HDL is more complex and not a reason to start drinking.
Age matters too. Cholesterol levels naturally rise through middle age as the liver becomes less efficient at clearing LDL. For women, this increase accelerates after menopause. For men, it tends to plateau around age 50 before gradually declining. Chronic kidney disease and type 2 diabetes both independently worsen lipid profiles through mechanisms involving insulin resistance and impaired cholesterol metabolism.