A lot of people starting keto notice their LDL cholesterol goes up on blood tests. It's one of the most common concerns — and one of the most debated topics in nutrition science.

In 2025, a study made the rounds in keto communities with a reassuring message: high LDL on keto doesn't lead to plaque in your arteries. It was shared widely. Many people used it as evidence that they didn't need to worry.

In 2026, that study was retracted by the journal that published it.

Here's what actually happened — and what it means for you.

What the study said

The paper, published in JACC: Advances, followed 100 people whose LDL had risen on a ketogenic diet. Researchers scanned their arteries for plaque buildup a year apart and reported that keto was not associated with plaque progression.

The finding spread fast. It fit a theory some keto researchers had been pushing: that LDL on a high-fat diet behaves differently than LDL on a high-carb diet, and that standard risk markers don't tell the whole story.

Why it was retracted

The journal pulled the paper after finding errors it described as "too great to be corrected." Independent scientists had flagged problems early: the study was small (100 people), had no proper control group, and reported results selectively.

A retraction doesn't mean fraud. It means the methodology had enough problems that the journal could no longer stand behind the conclusions. That's science working as it should — but it does mean this particular piece of evidence is no longer reliable.

What other research shows

The LDL question on keto is genuinely complicated, and mainstream medicine and keto researchers don't fully agree.

What the mainstream evidence says:

Most studies show LDL cholesterol rises for many people on a ketogenic diet (Harvard T.H. Chan). High LDL is a long-established risk factor for cardiovascular disease — this is the basis of standard medical guidance. The Cleveland Clinic notes that fat quality matters: replacing saturated fat with unsaturated fat tends to keep LDL in check, while a diet heavy in butter and processed meats tends to push it higher (Cleveland Clinic).

Where the debate is:

Some researchers argue that LDL on keto is different — that particle size and other markers matter more than the LDL number alone. This is a live scientific discussion. It hasn't been settled by the kind of large, long-term trials that would change clinical guidelines.

What this means for you practically

Don't panic. One retracted study doesn't mean keto is dangerous. It means one piece of evidence people were leaning on has been taken off the table. The underlying question is still open.

Check your numbers. If you're on keto and haven't had a lipid panel recently, it's worth getting one. LDL, HDL, and triglycerides together give a fuller picture. For many people, keto raises HDL and lowers triglycerides — both positive — even when LDL goes up. Your doctor can weigh these together.

Pay attention to fat quality. The type of fat you eat matters more than the amount. Olive oil, avocado, nuts, and oily fish tend to have better effects on your cholesterol profile than a diet heavy in butter and processed meats.

If your LDL is very high, talk to a doctor. Don't rely on internet discussions — or a retracted study — to decide whether a high number is fine for you specifically. A doctor or cardiologist can look at your full picture.

An honest note

There's real disagreement in nutrition science here, and it isn't going away soon. The keto community and mainstream cardiology are looking at the same data and reaching different conclusions. The retraction doesn't settle that debate — it removes one piece of evidence that was being used to close it prematurely.

The sensible position: keto has real benefits for many people, and the cholesterol question deserves monitoring, not dismissal.

New to keto? Start with What is the ketogenic diet? and What to eat on keto.

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