Can a ketogenic diet raise LDL cholesterol and apoB?

A ketogenic or very-low-carbohydrate diet can improve triglycerides and sometimes other metabolic measures while worsening LDL-related atherogenic markers in a subset of people. This pattern is clinically relevant because LDL-C and apoB convey different but complementary information: LDL-C reflects cholesterol carried within particles, whereas apoB approximates the number of circulating atherogenic apoB-containing particles.

Clinical evidence

• Across 53 randomized trials, ketogenic diets lowered triglycerides by a mean 22.3 mg/dL versus control diets while increasing LDL-C by 8.22 mg/dL on average.
• Effects can be much larger than the average: in a tightly controlled 4-week feeding trial of healthy normal-weight women, LDL-C increased by approximately 70 mg/dL.
• In a meta-analysis of normal-weight adults, LDL-C increased by 1.08 mmol/L (about 42 mg/dL) and apoB by 0.35 g/L, indicating that particle burden as well as cholesterol concentration can rise.
• In the Keto-Med crossover trial, triglycerides declined more but LDL-C rose more on keto than on a Mediterranean diet; HbA1c did not differ between diets.

Individual variation and interpretation

• LDL-C responses are highly heterogeneous. Lower BMI and a lower baseline triglyceride/HDL-C ratio have been associated with larger LDL-C increases, although these are exploratory rather than validated prediction tools.
• Susceptibility to an apoB increase is less well characterized. LDL-C and apoB can also be discordant: in a 2-year non-randomized controlled study, LDL-C increased without significant change in apoB or total LDL particle concentration.

Clinical implications

• Lower triglycerides, and even favorable glycemic markers, do not rule out a meaningful increase in LDL-C or apoB-containing particle burden.
• Bottom line: The claim is broadly supported: ketogenic diets can substantially raise LDL-C and, in some contexts, apoB despite favorable triglycerides or glycemic measures. Measuring apoB—not relying on triglycerides, HbA1c, or LDL-C alone—is important when LDL-C rises substantially.