Heart health
Keto raised my cholesterol. What do my results mean?
Reviewed by a qualified clinician · analysed at UKAS-accredited UK labs (ISO 15189)
Last reviewed October 20267 min read
Every Helvy guide is written by our health editors, then checked by a qualified clinician before it goes live and re-checked as the science moves. We name clinical roles, not individuals, until each reviewer has agreed to be credited publicly. This is wellness guidance to help you understand your own data, not a diagnosis.
QUICK ANSWER
A rise in LDL on keto is common. For most people it is small, while triglycerides fall and HDL rises. For some it is large. LDL above 5 mmol/L, or a high ApoB, is worth taking to a qualified clinician. ApoB and Lp(a) show more about heart risk than LDL alone.
Not sure which markers you need? Build your test →You cut the carbs, lost weight and feel sharper. Then a cholesterol result came back higher than before. Now you are reading that it either does not matter at all, or that it matters a lot.
As of October 2026, the debate is louder than ever. Podcasts keep returning to it. And in May 2026, the best-known study arguing that high LDL on keto is harmless was retracted by its journal. This guide shows you how to read your own numbers.
1. Is it normal for cholesterol to rise on keto?
Yes, it is common. Keto is a very low-carb, high-fat way of eating. More fat, and often more saturated fat, tends to push up LDL. LDL is the cholesterol carried in particles that can lodge in artery walls.
HEART UK, the cholesterol charity, puts it plainly.
“Ketogenic and other low carbohydrate diets have been consistently shown to increase total and LDL cholesterol.”
HEART UK, ketogenic diets
How much it rises varies a great deal. In a UK Biobank study published in 2024, 11.1% of people on a low-carb, high-fat diet had LDL above 5 mmol/L. On a standard diet, it was 6.2%. People whose genes already lean towards high LDL saw the biggest rises.
2. What does the usual keto pattern look like?
Three numbers usually move together. HEART UK summarised a 2024 review of trials comparing keto with higher-carb diets.
| Marker | Average change | Direction |
|---|---|---|
| LDL cholesterol | +0.35 mmol/L | Up |
| HDL cholesterol | +0.16 mmol/L | Up |
| Triglycerides | −0.20 mmol/L | Down |
Why do some people see a much bigger rise? Genes are one reason. Body size is another. A 2022 survey of 548 low-carb eaters found that the leaner people were, the more their LDL tended to climb. Some lean people see very large rises. This group is sometimes called “lean mass hyper-responders”.
What you eat on keto matters too. Butter, cream, cheese and fatty meat are high in saturated fat. Olive oil, nuts, avocado and oily fish are mostly unsaturated. Two people can both be “on keto” and get very different results.
HDL is the cholesterol carried back to the liver. Triglycerides are the fats in your blood that rise with sugar and refined carbs. So two of the three moves look good. The question is whether the LDL rise outweighs them.
3. How do I read my own numbers?
Look past LDL alone. LDL measures how much cholesterol the particles carry. It does not count the particles themselves.
- ApoB is a protein with one copy on each harmful particle, so it counts them.
- Non-HDL cholesterol is your total minus HDL, a wider view than LDL.
- Lp(a) is a particle type set mostly by your genes, not your diet.
- HbA1c shows your average blood sugar over two to three months.
| Your pattern | What your data suggests |
|---|---|
| LDL up a little, ApoB in range, triglycerides down | The common keto picture. Keep an eye on it at your next test. |
| LDL up a lot, ApoB high | More particles, not just fuller ones. Worth a talk with a clinician. |
| LDL above 5 mmol/L | Seen in about 1 in 9 low-carb eaters in UK Biobank. Get it reviewed. |
| Lp(a) high | Inherited, and diet will not shift it. It adds to the weight of any LDL rise. |
HbA1c often falls on keto, which is a real plus. It does not cancel out a large rise in ApoB, though. Each marker reads a different part of your heart risk.
A modest LDL rise with an ApoB in range is the common picture. A big LDL rise with a high ApoB is a different one. Our guide to normal ApoB levels shows the UK ranges and the risk-based goals.
Lp(a) matters because keto will not change it. A high Lp(a) adds to risk on any diet. It usually needs measuring once. Our Lp(a) levels guide explains the cut-offs.
4. When does a rise on keto matter?
When it is large, or when other risks sit beside it. The same UK Biobank study followed people for almost 12 years. Major heart and circulation events hit 9.8% of the low-carb, high-fat group and 4.3% of the standard-diet group.
That is about double the risk after allowing for other factors. The study has limits. Diet was self-reported in a 24-hour survey, and it shows a link, not proof of cause.
The risk looked highest where LDL climbed furthest. When the study was first presented, people on the diet with LDL above 5 mmol/L had more than six times the risk of standard-diet eaters with LDL under 3.5, as TCTMD reported.
Very high results deserve a closer look whatever you eat. NICE says to suspect familial hypercholesterolaemia, an inherited cause of high cholesterol, when total cholesterol is above 7.5 mmol/L. Keto can unmask it. Our cholesterol blood test guide covers the full set of numbers.
5. What about the study that said high LDL was fine?
It has been withdrawn. The KETO-CTA study scanned the heart arteries of 100 lean people with very high LDL on keto. Its 2025 paper said their plaque growth was not linked to ApoB or LDL.
The journal, JACC: Advances, retracted that paper in May 2026. The notice says concerns about its methods affected the reliability of the data. The authors and editors agreed.
A new analysis of the same group was posted in January 2026. It has not been peer reviewed. It reported a median 37% relative rise in soft plaque over one year. The honest summary: there is no good evidence that a big LDL rise on keto is safe.
6. When should I test?
Twice, ideally. Once before you start, so you have a baseline. Then again a few months in, once your eating has settled.
Triglycerides and LDL read most accurately after a 9 to 12 hour overnight fast. Our fasting blood test guide explains how to prepare.
If your LDL or ApoB has risen a lot, talk to a qualified clinician before you decide what to change. Swapping some saturated fat for unsaturated fats such as olive oil, nuts and oily fish is one option. Our guide to lowering cholesterol covers the rest.
7. Which test reads all of this?
A standard NHS cholesterol check gives you the lipid profile. It usually leaves out ApoB and Lp(a). Our Advanced Heart Health panel (£159) reads LDL, HDL, triglycerides and non-HDL with ApoB, Lp(a), hs-CRP and HbA1c. hs-CRP picks up low-level inflammation, another piece of the heart picture.
A blood test measures biomarkers. It offers wellness insight, not a diagnosis. The heart health hub has the rest of our heart guides.
READY TO TEST?
Ask your blood
Helvy’s home blood tests report your heart markers with plain-English context, so you can see what your diet is doing. Samples are processed by UKAS-accredited UK labs.
Frequently asked questions
Does keto raise cholesterol?
Often, yes. HEART UK says keto and other low-carb diets have been consistently shown to raise total and LDL cholesterol. Triglycerides usually fall and HDL usually rises. The size of the LDL rise varies a lot between people.
Is high LDL on keto dangerous?
A large rise should not be assumed to be harmless. In a UK Biobank study, people on a low-carb, high-fat diet had about double the rate of major heart events over almost 12 years. The study shows a link, not proof of cause.
What LDL level on keto should worry me?
LDL above 5 mmol/L is worth discussing with a qualified clinician. NICE says to suspect familial hypercholesterolaemia, an inherited cause, when total cholesterol is above 7.5 mmol/L.
Is ApoB better than LDL on keto?
ApoB counts the particles that carry cholesterol into artery walls, while LDL measures the cholesterol inside them. When LDL rises on keto, ApoB shows whether the number of particles has risen too.
Wasn't there a study showing high LDL on keto is fine?
The KETO-CTA paper in JACC: Advances made that case in 2025. The journal retracted it in May 2026 over concerns about its methods, with the agreement of the authors and editors.
When should I check my cholesterol on keto?
Before you start, for a baseline, and again a few months in once your eating has settled. A 9 to 12 hour overnight fast gives the most accurate triglyceride and LDL readings.