How to lower LDL cholesterol on a low-carb diet

Have you noticed your total cholesterol or LDL-C (low-density lipoprotein cholesterol) increases on a low-carb diet? Are you interested in learning how to lower your cholesterol numbers? This guide will explain what you can do to decrease your LDL while eating a low-carb diet.

Disclaimer: While a low-carb diet has many proven benefits, there are several aspects of it that remain controversial. One such aspect is how much significance to attribute to an elevated LDL on cardiovascular risk when evaluated in the context of a healthy, low-carb diet.

Discuss any changes in your labs, medications, and relevant lifestyle changes with your doctor. Full disclaimer

Other controversial topics related to a low-carb diet, and our take on them, include saturated fats, cholesterol, whole grains, red meat, salt, and restricting calories for weight loss.

Whether or not cholesterol is the most important risk factor for heart disease in people who eat a low-carb diet — and whether or not lowering it is important — remains to be proven.1 However, contemporary medical consensus is that elevated LDL increases cardiovascular risk. We recognize the difficult situation many people face if they have seen significant benefits from a low-carb lifestyle yet experience a rise in LDL.

It may be hard to imagine abandoning a way of eating that has helped you lose weight, improve blood sugar and insulin resistance, normalize blood pressure, decrease hunger, or provide other benefits. Fortunately, there are ways to lower your LDL without losing the many positive effects of a low-carb lifestyle.


Don’t confuse total cholesterol with LDL

Some doctors still focus on total cholesterol as an important number. However, since total cholesterol is made up of LDL and HDL cholesterol, we don’t know if increased total cholesterol is due to an increase in LDL, HDL, or both.

In addition to the possible effect of increasing LDL, low-carb diets are also well known for consistently raising HDL, which will in turn increase total cholesterol.2 However, elevated HDL is not a concern when it comes to cardiovascular risk. Therefore, before reacting to a higher total cholesterol level, make sure you know your breakdown between LDL and HDL.


Understand the difference between LDL-C and LDL-P

Most cholesterol blood tests measure LDL-C, the total amount of cholesterol carried in our LDL particles. However, LDL-P, or the total number of LDL particles in our blood, is an even better marker of cardiovascular risk.3 Some studies on low-carb diets have shown an increase in LDL-C with either no change or a decrease in LDL-P (or Apo B, which is a common proxy for LDL particles).4

How does this happen? Studies show that carbohydrate restriction can change small LDL particles into larger ones.5 Therefore, there may be more overall cholesterol, but fewer LDL particles. In theory, this may not indicate a substantially increased cardiovascular risk and may not require corrective action.6


How to lower LDL on low carb

 

Cut excess saturated fat

Sometimes a small change can make a significant difference. Although this is based mostly on clinical experience, simply eliminating extra liquid saturated fat may normalize LDL levels.7 That means eliminating MCT (medium-chain triglycerides) oil and butter in coffee, fat bombs, or other keto “treats.”

Some people may find that limiting their saturated fat intake to whole foods (beef, cheese, eggs, etc.) is all it takes to improve LDL levels.

Consider swapping saturated fats for unsaturated fats

For some, making small changes like the ones listed above won’t be enough to produce  a meaningful change in LDL. Instead, they may need to reduce saturated fat from all sources and replace it with mono- and polyunsaturated fats. In practice, that means less beef, cheese, and cream – and more fish, macadamia nuts, avocados, and olive oil.

Liquid polyunsaturated fats, such as seed oils, remain a point of contention. This is because observational studies show a small cardiac benefit, but randomized, controlled trials (RCTs) show they can reduce LDL but may increase both cardiovascular events and risk of dying.8 Furthermore, mechanistic data suggest seed oils can increase oxidation and inflammation, although clinical trials haven’t shown this.9 See more in our evidence-based guide to vegetable oils.

Another option is to switch to a vegetarian or vegan keto/low-carb diet, which is typically lower in saturated fat. You can find more details in our guides on vegetarian and vegan low-carb diets.

Many people find that reducing or eliminating saturated fats while still remaining on a LCHF diet successfully lowers LDL cholesterol. The more pressing question is if this is a sustainable eating pattern. The answer is highly individualized and requires personal experimentation.

Eat plenty of fiber

Fiber-rich and keto-friendly foods like avocados, leafy greens, nuts and seeds could potentially lower LDL cholesterol.10 However, if increasing your intake of these foods adds too many carbs, consider supplementing with 5 grams of psyllium husk twice a day to lower LDL.11

Practice time-restricted eating

Although there aren’t much data on time-restricted eating and lipids, a small pilot study showed a significant reduction in LDL-C in people who consumed all food within a 10-hour window.12 Although we need more data, it makes sense that combining this practice with some of the other tips in this guide could have additive LDL-lowering effects.

Know your carbohydrate threshold

The last option to consider is increasing the amount of carbohydrates you eat. Sometimes it pays to ask, do you need to be in ketosis? Or would a low-carb diet of 50 or even 100 grams of carbs suffice for your health goals?

If you have controlled your diabetes and want to make sure it remains controlled, then you might need to remain in ketosis. If, however, you tried a ketogenic diet primarily to reduce your cravings and lose a little weight, you may find you can safely increase your carb intake.13 See our detailed guide on carbohydrate intake for more information.

The important point is being mindful and honest with yourself about how things change when you add in more carbs. And remember, not all carbs are the same. Even if you raise your daily carb intake to 100 grams per day, that doesn’t mean grains and sugars are back on the menu.

Try to stick with starchy veggies, fruits and legumes as your main source of “new” carbs. If you notice a return of your cravings, a loss of control, or other negative effects, you may want to go back to a stricter carb limit in order to avoid undoing the health progress you’ve made.

Experiment

Since many people react differently to the interventions listed above, we encourage you to perform your own series of personal experiments. Here are important questions to ask before starting:14

  1. Do I want to change one thing at a time or many things at once? If you want to find the one change that has the most meaningful impact, it’s best to change only one thing at a time. For example, just cut out your butter coffee, but still eat steak, cook with cream, and keep your carbs below 20 grams. That will help answer your single question.

    If instead, you want to achieve results as quickly as possible, then you’ll want to use as many interventions as you can. If you succeed, then you can either continue on your new path or start adding things back in, one at a time. For instance, maybe you’ll want to add back steak twice per week and then retest to see if your labs remain in a range with which you’re satisfied.

    The key is finding a lifestyle you can maintain long term. It’s hard to achieve lasting benefits if you’re so restrictive that you often feel deprived.

  2. How long do I need to wait? Cutting out butter and MCT oil in your coffee for a week is unlikely to have a meaningful impact on your lab values. But how long is long enough?

    There isn’t a clear answer, but in general most practitioners feel 6 weeks is the minimum time to expect a meaningful change, although many acknowledge you may not see the maximal effect for 3 to 6 months.15 That can make it difficult to know if you gave your experiment adequate time. One option is to retest at 6 weeks and then again at 3 months to chart a trajectory, and then decide if further testing could be helpful or not.

  3. What lipid tests should I follow? Mainstream cardiology tends to focus mostly on LDL-C and not LDL-P or LDL size and density. This is partly because statins and other lipid-lowering drugs do not change the size and density of the LDL, and they may lower LDL-C more than LDL-P.16Nutritional changes, on the other hand, seem to be more effective at improving LDL-P and LDL size.17 Therefore, when measuring the impact of lifestyle changes on your lipids, we recommend getting advanced lipid testing that includes LDL-P and the size of the LDL particles.

    Unfortunately, in the U.S. and other countries, insurance may not cover these tests, so you may have to pay out of pocket for them. If that is prohibitive, you may be able to use the triglyceride-to-HDL ratio as a surrogate for the size of LDL particles. It isn’t perfect, but it does tend to correlate with metabolic health.

    Studies show that TG/HDL ratios correlate with cardiovascular risk and cardiovascular mortality. Although there isn’t universal agreement on ideal levels, studies suggest greater than 4 is high risk, and clinical consensus is that less than 2 is a reasonable target, with lower being better (assuming HDL is above 40).18 Studies also show the ratio is correlated with insulin resistance in adults and children.19 You can follow your trend to make sure the ratio is not increasing, since in most circumstances lower is better.

  4. What else should I measure? Remember that LDL is not the only cardiovascular risk factor. If your goal is lowering LDL, it’s important to make sure other markers don’t suffer as a result. Therefore, we suggest following simple metrics such as your weight,  waist circumference, and blood pressure; markers of insulin resistance, including fasting glucose and insulin levels (and a calculated HOMA-IR); and HbA1c to monitor long-term blood glucose control. Learn more about insulin resistance in our evidence-based guide.

Please remember to work with your healthcare provider so he or she is aware of your experiments to ensure safety, especially if you are on medications for diabetes, high blood pressure, or cholesterol.


You can be in control

With the above steps, you can take control by designing your own experiments to see how you can best alter your lab results. Just remember to focus on your entire health picture; the goal should be lowering your LDL without losing any of your low-carb benefits. Work with your doctor to ensure safety and efficacy. And if you need a doctor more familiar with low carb, be sure to check out our low-carb doctors directory.

/ Dr. Bret Scher

 


  1. A point of contention in lipid research is that few – if any – trials focus on people following a whole-food, low-carb diet. Therefore, it is unknown if the conclusions from studies of people following a low-fat diet or standard Western diet are applicable to those on a low-carb diet.

    Most experts in the field of lipidology assume the risk is the same, although some question this. In the absence of specific data, some may choose to be more conservative while others may be more permissive with “elevated” levels.

  2. The British Journal of Nutrition 2016: Effects of low-carbohydrate diets v. low-fat diets on body weight and cardiovascular risk factors: a meta-analysis of randomised controlled trials [strong evidence]

  3. Journal of Clinical Lipidology 2011: Clinical implications of discordance between LDL cholesterol and LDL particle number [observational study; weak evidence]

    Journal of Clinical Lipidology 2007: LDL Particle Number and Risk of Future Cardiovascular Disease in the Framingham Offspring Study – Implications for LDL Management [observational study, weak evidence]

    Journal of the American College of Cardiology 2007: Value of low-density lipoprotein particle number and size as predictors of coronary artery disease in apparently healthy men and women: the EPIC-Norfolk Prospective Population Study [observational study, weak evidence]

  4. Cardiovascular Diabetology 2018: Cardiovascular disease risk factor responses to a type 2 diabetes care model including nutritional ketosis induced by sustained carbohydrate restriction at 1 year: an open label, non-randomized, controlled study
    [non-controlled study; weak evidence]

    Journal of Nutrition 2005: Modification of lipoproteins by very low-carbohydrate diets [overview article; ungraded]

    Frontiers in Medicine 2020: A Standard Lipid Panel Is Insufficient for the Care of a Patient on a High-Fat, Low-Carbohydrate Ketogenic Diet [case report; very weak evidence]

  5. Cardiovascular Diabetology 2020: Impact of a 2-year trial of nutritional ketosis on indices of cardiovascular disease risk in patients with type 2 diabetes [nonrandomized study, weak evidence]

    Lipids 2009: Carbohydrate restriction has a more favorable impact on the metabolic syndrome than a low fat diet [randomized trial; moderate evidence]

    Archives of Internal Medicind 2004: The national cholesterol education program diet vs a diet lower in carbohydrates and higher in protein and monounsaturated fat: a randomized trial. [moderate evidence]

  6. This is a hypothesis that has not been proven in long-term studies but is based on some data suggesting that smaller LDL particles have a higher association with cardiac risk than do larger particles, as well as that LDL-P is a better measure of risk than LDL-C as referenced in the text.

  7. This is based on clinical experience of low-carb practitioners and was unanimously agreed upon by our low-carb expert panel [weak evidence]. You can learn more about our panel here.

  8. Weak-quality observational studies show a small improvement in cardiovascular outcomes:

    Circulation 2014: Dietary linoleic acid and risk of coronary heart disease: a systematic review and meta-analysis of prospective cohort studies [meta-analysis of observational studies; weak evidence]

    Recently recovered data from randomized clinical trials showed diets higher in vegetable oils and lower in saturated fat did indeed lower total blood cholesterol. Yet the lower cholesterol level did not improve mortality rates:

    British Medical Journal 2016: Re-evaluation of the traditional diet-heart hypothesis: analysis of recovered data from Minnesota Coronary Experiment (1968-73) [strong evidence]

    British Medical Journal 2013: Use of dietary linoleic acid for secondary prevention of coronary heart disease and death: evaluation of recovered data from the Sydney Diet Heart Study and updated meta-analysis [strong evidence]

    And extensive reviews of RCTs likewise show no correlation between seed oil use and improved cardiovascular events:

    The British Journal of Nutrition 2010: n-6 fatty acid-specific and mixed polyunsaturate dietary interventions have different effects on CHD risk: a meta-analysis of randomised controlled trials. [strong evidence]

  9. Journal of Nutrition and Metabolism 2012: Health implications of high dietary omega-6 polyunsaturated fatty acids [overview article; ungraded]

    Journal of the Academy of Nutrition & Dietetics 2012: Effect of dietary linoleic acid on markers of inflammation in healthy persons: a systematic review of randomized controlled trials [strong evidence] 

  10. Journal of Clinical Lipidology 2016: Impact of avocado-enriched diets on plasma lipoproteins: A meta-analysis [systematic review of randomized controlled trials; strong evidence]

    Archives of Internal Medicine 2010: Nut consumption and blood lipid levels: a pooled analysis of 25 intervention trials. [strong evidence]

  11. American Journal of Clinical Nutrition 2000: Long-term cholesterol-lowering effects of psyllium as an adjunct to diet therapy in the treatment of hypercholesterolemia [randomized trial; moderate evidence]

  12. Cell Metabolism 2019: Ten-hour time-restricted eating reduces weight, blood pressure, and atherogenic lipids in patients with metabolic syndrome [non-controlled study; weak evidence]

  13. This is based on the consistent clinical experience of low-carb practitioners. [weak evidence]

  14. These are based on clinical experience rather than specific scientific studies.

  15. This is based on the clinical experience of low-carb clinicians [weak evidence].

  16. Texas Heart Institute Journal 2010: Statins do not decrease small, dense low-density lipoprotein [prospective cohort study;weak evidence]

    Cardiovascular Drugs and Therapeutics 2013: Systematic review: Evaluating the effect of lipid-lowering therapy on lipoprotein and lipid values. [systematic review of randomized trials; strong evidence]

  17. Cardiovascular Diabetology 2018: Cardiovascular disease risk factor responses to a type 2 diabetes care model including nutritional ketosis induced by sustained carbohydrate restriction at 1 year: an open label, non-randomized, controlled study
    [non-controlled study; weak evidence]

  18. American Heart Journal 2009: The TG/HDL cholesterol ratio predicts all cause mortality in women with suspected myocardial ischemia: A report from the women’s ischemia syndrome evaluation (WISE)
    [observational study, weak evidence]

  19. American Journal of Cardiology 2008: Comparison of serum lipid values in subjects with and without the metabolic syndrome.
    [observational study, weak evidence]

    Scientific Reports 2017: Triglyceride to HDL-C ratio is associated with insulin resistance in overweight and obese children
    [observational study, weak evidence]