Your Cholesterol Went Up on Keto. Here Is What That Actually Means.
You went low-carb. You lost weight. Your blood sugar stabilized, your energy came back, and you feel better than you have in a decade. Then you got your bloodwork back and your doctor looked worried. Your LDL went up. Maybe it went up a lot.
Before you panic, or worse, abandon the diet that is clearly working for you, it is worth understanding what that number actually tells you. And more importantly, what it doesn't.
Cholesterol is not your enemy
Cholesterol is one of the most important molecules in your body. Your body produces it on purpose. It builds every cell membrane you have. It is the raw material for testosterone, estrogen, progesterone, and cortisol. It produces vitamin D and bile acids. Your brain is largely made of it.
Dr. Eric Westman, director of the Duke Lifestyle Medicine Clinic and one of the most experienced keto researchers in the country, has spent decades helping patients understand that cholesterol is not a substance the body makes by accident. It is a molecule of life. The fear around it has very little to do with biology and a great deal to do with how cardiovascular research was interpreted, funded, and communicated over the past fifty years.
What actually happens to cholesterol on keto
Most people who adopt a low-carb or ketogenic diet see their triglycerides drop and their HDL rise. Both of those are positive changes. A smaller group sees their LDL go up as well. An even smaller group sees it go up significantly. Researchers now call these people hyper-responders.
Here is something worth knowing. It is not unusual for LDL to rise during active weight loss on any diet. Dr. Stephen Phinney documented this more than thirty years ago, calling it transient hypercholesterolemia. When your body is burning stored fat for fuel, it releases fatty acids into the bloodstream. That process temporarily affects how cholesterol is packaged and transported. Once your weight stabilizes, LDL often comes back down.
Researchers studying low-carb diets in people with type 2 diabetes have written that an increase in LDL during this period may represent a normal physiological process rather than a pathological one. In other words, it may be your body doing exactly what it is supposed to do.
The number your doctor should be looking at
If you want a meaningful window into your cardiovascular risk, stop looking at your total cholesterol number. Start looking at your triglyceride to HDL ratio.
Dr. Paul Mason, a sports and exercise medicine physician whose work on lipids and metabolic health has reached millions, points to this ratio as one of the most clinically useful markers available. A ratio below 1.5 is considered optimal. Between 1.5 and 3.5 is acceptable. Above 3.5 signals a pattern associated with insulin resistance and small, dense LDL particles, which are the particles actually linked to cardiovascular risk.
A keto diet almost universally improves this ratio. Triglycerides fall. HDL rises. The ratio moves in the right direction regardless of what happens to LDL.
How to actually assess your cardiovascular risk
If your LDL is elevated and you want a real answer about your heart health, ask your doctor about a coronary artery calcium scan, or CAC scan. This test measures actual calcification in your coronary arteries. It tells you whether atherosclerosis is present, not whether a molecule associated with it is elevated.
Research published in the journal Atherosclerosis found that direct assessment of atherosclerosis is more predictive of coronary artery disease than traditional risk factors including blood cholesterol. A CAC score of zero means the likelihood of coronary artery disease is extremely low, regardless of your LDL number.
The test costs less than $200 in most parts of the United States. It gives you far more useful information than a standard lipid panel.
What this means for you
If your cholesterol went up on keto and everything else improved, that is a pattern worth understanding, not a reason to stop. Work with your doctor. Ask for the full picture. Request your triglyceride to HDL ratio. Ask about a CAC scan if you want to know your actual cardiovascular status.
A single number on a standard lipid panel is not a diagnosis. It is a starting point for a conversation you deserve to have with accurate information.
Disclaimer: This article is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before making changes to your diet, lifestyle, or treatment plan.
References:
Phinney SD, Tang AB, Waggoner CR, Tezanos-Pinto RG, Davis PA. The transient hypercholesterolemia of major weight loss. Am J Clin Nutr. 1991 Jun;53(6):1404-10.
Wheatley SD, Deakin TA, Arjomandkhah NC, Hollinrake PB, Reeves TE. Low Carbohydrate Dietary Approaches for People With Type 2 Diabetes: A Narrative Review. Front Nutr. 2021 Jul 15;8:687658.
Volek JS, Fernandez ML, Feinman RD, Phinney SD. Dietary carbohydrate restriction induces a unique metabolic state positively affecting atherogenic dyslipidemia, fatty acid partitioning, and metabolic syndrome. Prog Lipid Res. 2008 Sep;47(5):307-18.
da Luz PL, Favarato D, Faria-Neto JR Jr, Lemos P, Chagas AC. High ratio of triglycerides to HDL-cholesterol predicts extensive coronary disease. Clinics (Sao Paulo). 2008 Aug;63(4):427-32.
Raggi P. Coronary calcium is all we need for risk assessment, yet we do not use it often enough. Atherosclerosis. 2019 Mar;282:167-168.
Westman EC, Tondt J, Maguire E, Yancy WS Jr. Implementing a low-carbohydrate, ketogenic diet to manage type 2 diabetes mellitus. Expert Rev Endocrinol Metab. 2018 Sep;13(5):263-272.
