Myth or fact

A high ApoB on keto is fine if your triglycerides are low

Short answerNot the way you think

By GyroscopeUpdated November 15, 20266 sources

Not the way you think. Low triglycerides on keto are real, and so is the weight loss. But the particle count is what predicts heart disease. In a study of 654,783 people, genes that lowered ApoB cut the odds of heart disease by the same amount per point whether they did it through triglycerides or through LDL. A high ApoB carries the same weight on keto as anywhere else.

Why people believe it

A lot of people on keto get two results at once. Their triglycerides fall, which on most panels counts as good news. For some of them, LDL climbs a long way, and ApoB with it. The story that ties those together goes like this. With so little carbohydrate, the body ships fat around in a different way, the particles are big and fluffy, and big fluffy particles are harmless. On that story, a high ApoB with low triglycerides is a sign the diet is working.

The 2026 US guideline agrees with the first half, saying ketogenic diets “are associated with significant short-term weight and TG reduction”, and nothing in it supports the second.

What the guideline says

The guideline lists ketosis, a high saturated fat intake and rapid weight loss among the causes of high LDL. It says that on a ketogenic diet “LDL-C can be increased substantially in some individuals, particularly when there is high consumption of animal products”. Because most of the carbs are replaced by fat, “often saturated fat, some individuals, with or without lipid disorders, may manifest a severe hypercholesterolemia phenotype”.

It asks doctors to take a “careful dietary history” from anyone with severe high cholesterol, to rule out a high saturated fat diet. For people whose cholesterol rose on keto, it says they “should be counseled on ways to mitigate the LDL-C elevation while still achieving the primary goal of the dietary change”. Keep the goal and change how you get there.

Why low triglycerides don’t cancel a high count

In 2019 Ference and his colleagues looked at the genes of 654,783 people. Some carried genes that lower triglycerides, and some carried genes that lower LDL. Both kinds lower ApoB. For each 10 mg/dL lower ApoB, the odds of heart disease were 0.771 with the triglyceride genes and 0.773 with the LDL genes. The route didn’t change the result. What counted was how far the particle count fell.

That’s the part of the keto story that doesn’t hold. If low triglycerides protected you on their own, the triglyceride genes would have done better per point of ApoB, and they didn’t. When a 2022 study of 429,959 people put ApoB, LDL and triglycerides in the same model, “only apoB” stayed tied to heart attacks.

Like a road with fewer fuel tankers and more trucks

Picture a highway. On a normal diet some of the traffic is fuel tankers, carrying triglycerides. Keto takes most of the tankers off the road, which looks great from above. But if the number of trucks goes up at the same time, the road is busier than before, and the guardrail gets hit by trucks, whatever they’re hauling. Your triglycerides tell you about the tankers, and your ApoB counts every vehicle.

The best case for the myth

The strongest version goes like this. The studies behind ApoB were done on people eating ordinary diets, not lean, active people on keto with low triglycerides and high HDL, and nobody has run a long trial in that group. That’s true, and we don’t know for certain what a high ApoB does in a lean, fit person on keto over 20 years.

What we have is the gene research, where the benefit per point of ApoB was the same however it got there, and the head-to-head studies, where ApoB beat triglycerides. UK Biobank also showed that triglycerides tell you little about the count. At triglycerides of 115, people’s ApoB ranged from 68 to 147. With no evidence that a high count is safe in any group, we’d treat it the way we treat it everywhere else.

What to do

1. Get your number. ApoB, LDL and triglycerides at a lab you’ll use again. If it’s 140 or more, see a doctor first.
2. Swap the fat, keep the carbs low. Olive oil instead of butter, nuts and avocado instead of cheese, fish and tofu more often than fatty meat. In a feeding trial, halving saturated fat took ApoB down about 6 to 7 points on an ordinary diet.
3. Retest after a month or two. Same lab. A change has to pass about 15% to be probably real.

cholesterol.guide covers what keto does to the rest of your panel, and bodyfat.guide covers whether cutting carbs burns more fat.