Catabolism: What Is Catabolism?

Definition

Catabolism is the half of metabolism that breaks things down. Anabolism builds. You do both every day. Fitness marketing turned “catabolic” into a scare word for skipping a shake.

When it matters

A hard deficit plus no lifting plus low protein is how you donate muscle to the cut. The fix is not a branded anti-catabolic powder. It is lifting in a sensible deficit with enough protein. Related: complete protein.

Reviewed September 2026. Not medical advice.