Elevated LDL-cholesterol levels among lean mass hyper-responders on low-carbohydrate ketogenic diets deserve urgent clinical attention and further research.

• Lean mass hyper-responders exhibit extreme increases in LDL-c on ketogenic diets. • LDL-c increases in LMHRs are dependent on carbohydrate restriction. • Other cardiometabolic risk factors are normal to optimal in LMHRs. • A prudent clinical approach is required for managing LDL-c in LMHR patients. • Research is warranted to assess mechanisms and cardiovascular risk of this trait. [ABSTRACT FROM AUTHOR]