I’m supposed to have my cholesterol checked soon. It’s a simple test, but I’m not looking forward to it since it requires fasting overnight. And that means making a special early-morning trip to my doctor’s office.

But new international guidelines say it’s OK — even preferred — to skip the overnight fast.

To learn more about this small but oh-so-useful shift, I talked with cardiologist Dr. Samia Mora. She helped write the new guidelines, which were published this week in the European Heart Journal and summarized in JAMA Internal Medicine. Mora is director of the Center for Lipid Metabolomics at Brigham and Women’s Hospital and associate professor of medicine at Harvard Medical School.


What was the point of fasting before having a cholesterol test?

Not eating for eight to 12 hours before having blood drawn for a cholesterol test was thought to give a more accurate assessment of total cholesterol, harmful LDL cholesterol, protective HDL cholesterol, and triglycerides, a type of fat-carrying particle. We now know better.

One problem with fasting is that we spend most of the day in the nonfasting state, so the way cholesterol tests are currently done doesn’t necessarily give a clear picture of “normal” levels. Another is that fasting is a hassle for everyone concerned — patients, clinicians, and even lab workers.


What’s behind the new recommendation?

This change has been coming for some time. It is driven by data from a dozen-plus studies that include more than 300,000 people whose cholesterol and other lipids were measured when they hadn’t fasted. Their levels predicted cardiovascular risk, as well as, or possibly better than, fasting lipid levels.

Nonfasting levels might be better?

After you eat, your digestive system converts some of the carbohydrates and fats into triglycerides. Their level in the bloodstream rises, then gradually falls. If the triglyceride level rises too much, it’s a signal that the body has trouble metabolizing food. Think of eating as a stress test for metabolism. That’s something you can’t see if you’ve been fasting.

What does this shift mean?

Everyone wins with this change. People don’t like to fast overnight. Some find it difficult to do, others are even harmed by it, such as those who faint from fasting and people with diabetes who take medications to lower blood sugar. The new recommendation means you can have your blood drawn when it’s most convenient for you, rather than early in the day.

It may even mean one-stop shopping — you can have your blood drawn and then see your doctor, all in the same visit. It’s easier for clinicians, who don’t have to keep track of patients’ special lab visits. Eliminating the fasting requirement will benefit labs, too, since they won’t have to deal with the daily crush of patients first thing in the morning needing blood draws for cholesterol checks.

Does what you eat before the test matter?

Consuming a double cheeseburger, fries, and a milk shake right before having your blood drawn for a cholesterol test may lead to a follow-up fasting test if the triglycerides are very high. But eating normally has little effect on your lipid levels, including triglycerides.

Will this recommendation catch on in the United States?

Health care providers often do what they are used to doing, so it may take a while for some to change to nonfasting cholesterol tests. But we also need to realize that there are advantages to this evidence-based change. Switching to nonfasting cholesterol testing is actually the path of least resistance for patients and clinicians. It also provides a more accurate lipid profile for individual patients.

I believe that getting the word out to clinicians, lab directors, and patients will be enough to make the switch to nonfasting cholesterol tests in a fairly short time.

  • Received my first high reading last year from non-fasting. I am now taking Lipitor due to high cholesterol. I guess the previous 10 annual reading were incorrect. My next test this year will be based on fasting. If the number is in the normal range I am stopping the Lipitor.

  • I think someone is getting a kick back from the drug companies. 😳I also know that a nonfasting test WILL render higher than normal results. Who cares if it’s inconvenient for someone to come to the doctor early to have their blood drawn, that’s just one more medication they don’t have to have. Get real, Ive seen this happen with my own two eyes, fasting versus non-fasting. Nonfasting was five points higher on triglycerides and LDL. I think whoever is trying to change this is wrong. There’s going to be a lot of people taking medicines that They don’t even need. Sure everybody should eat a healthy diet. But telling patients not to fast, to me, is considered unacceptable. Somebody is getting a kickback is just that simple

    • You cannot use antidotal experience as evidence in science. Abnormal lipids are normally treated with diet/exercise initially and those individuals who are high risk(Diabetics, Heart Patients) are treated with statin medication regardless of their lipid profiles.

  • “Another is that fasting is a hassle for everyone concerned — patients, clinicians, and even lab workers.”
    Explain how patients having to fast before a blood test is a hassle for lab worker (or doctors come to that)!? The lab worker gets a blood test and puts it in a machine. If it is a hassle or not should be irrelevant, all that counts is clinical efficacy.

    • When working in an outpatient lab setting, a phlebotomist may encounter a rush early in the morning. Reasoning to this is because when you “fast”, normally, people do so overnight. Guess what happens when you open the lab first thing? Yeah, just like Black Fridays at times. It creates an inconvenience to patients to have to wait.

    • Oh and btw, we do not simply just put it in a machine. Visit your local lab on the process before making a comment as such.

  • The database of statistics defining risk levels for LDL are based on fasting. Surely changing to non fasting will change those risk levels? This makes the logic of this proposed change hard to understand

  • These seem to be a classic example of lipid results that cannot be improved by a cholesterol lowering drug, but will respond very quickly to a low carbohydrate diet.
    If you stop eating all sugar and refined starch and replace it with vegetables and fat (assuming you already eat a proper amount of natural protein doors) your dangerously high triglycerides will drop and HDL rise.
    Have you had HbA1c checked?
    Always read lipids non fasting. I have checked my old test results and LDL and total cholesterol in my non-fasting results are always higher as well as triglycerides; it would be entirely unsafe to medicate based on non fasting results.
    But the HDL doesn’t change and in your test this is too low, usually a sign the diet is too high in carbohydrate for your degree of insulin sensitivity.
    Exercise will also help, HIIT and weights best.

  • total cholestrol value 190 , tryglycerides 382 mg/dl hdl cholestrol 33 mg/ dl . ldl cholestrol 80.6 mg / dl .vldl 76.4 mg/ dl . medicine want to start or not . what are the excercise and diet

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