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Here’s Why Diet Isn’t The Only Possible Reason For High Cholesterol

Medically reviewed by Rosanna Sutherby, PharmD on Feb 6, 2019. Written by Caitlin Boyd. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

“Why is my cholesterol high?” If you find yourself asking that, you aren’t alone. High cholesterol, a well-known risk factor for heart disease and stroke, affects about 1 in every 3 American adults. That’s arguably a pretty large proportion of adults who have high cholesterol – and it raises the question: why is high blood cholesterol so common?

Dietary habits, as many people know, are often responsible for high levels of cholesterol: eat a lot of foods high in saturated fat – cheeseburgers, for instance – and your blood cholesterol level might swing upwards. (We know, they’re delicious.)


While a diet high in saturated and trans fat can increase your total cholesterol level and cause high LDL and triglyceride numbers, this isn’t always the whole picture when it comes to cholesterol levels: high blood cholesterol can make an unwelcome appearance even if you’re very careful about eating a healthy, balanced diet.

Here’s why: there are other potential drivers of high cholesterol, such as a lack of exercise and one’s genetics. (So it can be helpful to check your blood cholesterol levels regardless of your dietary habits – something you can now do from the convenience of home with our home cholesterol test. You can also check up on indicators of your heart health at home with our Heart Health Test.)

So read on to take a closer look at both of these non-dietary reasons for high cholesterol if you’re wondering “Why is my cholesterol high when I eat healthy foods?”

(1) Lack of exercise

Truth be told, it’s not always easy to find the time – or the motivation – to consistently exercise. But take note: regular physical activity is an absolute must if you want to safeguard your body’s health and well-being. Exercise, after all, has many benefits – both physiological and psychological (“there is irrefutable evidence,” wrote one group of researchers, that regular physical activity can help prevent many chronic diseases and premature death). Incorporating exercise or workouts into one's schedule and eating a balanced diet are both lifestyle changes that are often recommended for people who want to maintain a healthy weight and lower LDL.

On the flip side, a lack of exercise frequently comes with a variety of health consequences – some of them rather severe. One health consequence, for example, is an increased risk of gaining an unhealthy amount of weight.

Over the long term, a lack of exercise can lead to obesity – which, in turn, can significantly lift cholesterol levels. In fact, up to 70% of patients with obesity have abnormalities in their cholesterol and triglyceride levels. Importantly, when obesity causes a high cholesterol level in the body, it’s – more often than not – the levels of “bad cholesterol” (LDL cholesterol) that tick upward. But levels of “good cholesterol” – or HDL cholesterol – on the other hand, are often low. (If you have a high triglyceride level and/or LDL level, it’s a good idea to talk with your healthcare provider to learn what steps to take next. Possible therapies may be medication, including more omega-3-rich foods that lower triglycerides in your diet, and more.)

And there’s more: obesity can elevate the amount of small dense LDL particles in the bloodstream. These LDL particles – very small in size, as their name suggests – can easily slip into the walls of your arteries (the vessels that carry blood from the heart to the rest of the body), prompting a plaque buildup. The arteries affected by plaque buildup frequently harden and narrow as a result, significantly slowing blood flow – a condition known as atherosclerosis. Alarmingly, the risk of suffering from a stroke or heart attack shoots up when your arteries are in this condition.

arteryplaque (1) Small dense LDL particles can easily slip into the walls of your arteries, causing a buildup of plaque. The affected arteries frequently harden and narrow as a result (illustrated here), significantly slowing blood flow. Source: National Library of Medicine (US). Genetics Home Reference. Illustration: Plaque in an artery wall. (Cited Jan 31, 2019.)

With all this in mind, then, if you are overweight or obese it’s important to routinely check your cholesterol levels (which you can do at home with the Everlywell Cholesterol and Lipids Test). And if your cholesterol levels are in fact too high, consult with your health care provider on the next steps to take that’d be best for you. Regulating cholesterol levels in your body may help improve your heart health and overall well-being.

## (2) Genetics

Has someone in your family had a heart attack even though they were fairly young? If your answer is “Yes,” you could be at a risk for “familial hypercholesterolemia” – an inherited, genetic lipid disorder that’s characterized by high blood cholesterol levels at a young age and a higher-than-normal risk of heart disease. (Also: if you answered “Yes” to that question, consider checking your cholesterol levels with an at-home cholesterol test kit that lets you collect a sample from the convenience of home and send it to a lab for testing. And, of course, be sure to consult with your healthcare provider.)

In women, for example, untreated familial hypercholesterolemia leads to a 30% risk of a coronary event (such as a heart attack) by age 60. That risk climbs to 50% in men by age 50.

What's more, this genetic condition can cause elevated cholesterol even if someone eats a well-balanced diet and gets regular physical activity—something to keep in mind if you’ve wanted to find out more about the causes of high cholesterol in a “healthy” person.

So what is it exactly about this genetic lipid disorder that causes cholesterol levels to reach disturbingly-high levels?

To answer that, we need to talk about something called “LDL receptors.” LDL receptors are special devices on the surface of many of your body’s cells. Their job description is straightforward: to catch particles of LDL cholesterol flowing in the bloodstream and take them inside the cell (where the LDL cholesterol is broken down).

In this way, LDL receptors continually clear your LDL cholesterol from the bloodstream – so there’s much less LDL cholesterol around to gum up the arteries with plaque.

But if you have familial hypercholesterolemia, your cells don’t have very many of these receptors – so particles of LDL cholesterol build up in your bloodstream faster than they can be cleared away.

How do you know if you’ve inherited this disorder?

A cholesterol level that’s much higher than average for your age is one clue (note that you can check your cholesterol and lipid levels at home with a cholesterol test collection kit).

However, if you’re concerned about familial hypercholesterolemia, you should definitely consult with your healthcare provider – since only a qualified healthcare professional will be in a position to make an accurate diagnosis.


1. Cholesterol. Centers for Disease Control and Prevention. URL. Accessed Feb 6, 2019.

2. Saturated Fat. American Heart Association. URL. Accessed Feb 6, 2019.

3. Warburton DE, Nicol CW, Bredin SS. Health benefits of physical activity: the evidence. CMAJ. 2006;174(6):801-809. doi:10.1503/cmaj.051351

4. Defining Adult Overweight and Obesity. Centers for Disease Control and Prevention. URL. Accessed Feb 6, 2019.

5. Feingold KR, Grunfeld C. Obesity and Dyslipidemia. In: Feingold KR, Anawalt B, Boyce A, et al., editors. Endotext [Internet]. South Dartmouth (MA):, Inc.; 2000. Available from: URL. Accessed Feb 6, 2019.

6. Knowing Your Risk for High Cholesterol. Centers for Disease Control and Prevention. URL. Accessed Feb 6, 2019.

7. Youngblom E, Pariani M, Knowles JW. Familial Hypercholesterolemia. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews [Internet]. Seattle (WA): University of Washington, Seattle; 2014. Available from: URL. Accessed Feb 6, 2019.

8. LDLR gene. Genetics Home Reference. URL. Accessed Feb 6, 2019.

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