In physique athletes, transient improvements in HDL and VLDL lipid profiles during fat loss revert to baseline levels after 5 months of weight regain, indicating no lasting cardiometabolic benefit from short-term dieting.

When body fat decreases, the liver and fat tissue stop producing signals that block fat-burning enzymes, allowing those enzymes to break down harmful fat particles in the blood. The fat released from those particles moves to good cholesterol particles, making them larger and more effective at removing cholesterol from arteries. When weight returns, fat tissue grows back, those blocking signals return, fat-burning enzymes slow down, and the good cholesterol particles shrink and lose their protective fats, returning to their original state.