Is Very High LDL on Keto Safe if You Are Lean and Fit?
If your LDL cholesterol climbs above 200 mg/dL after you start a ketogenic diet, being lean, active, high-HDL, and low-triglyceride does not prove your arteries are protected. The direct imaging evidence is thin: one coronary CT angiography study of lean keto dieters found no greater plaque at one scan after several years on the diet, but the follow-up paper meant to track whether plaque worsened was retracted. Against that sits far stronger human evidence that apolipoprotein B (apoB), a protein found one-per-particle on many cholesterol transport particles that can enter artery walls, marks particles that causally drive plaque buildup over years of exposure. The honest answer is not to panic, but not to treat this pattern as a proven safe exception either.