That’s a bad example. This is typically how it goes. Overweight person goes on that diet loses tons of weight, joints feel better, mood is better, gets off meds. Then goes to doctor and his cholesterol went up, so doctor recommends he stops eating meat.

Sure, if your ‘vital signs’ worsen then that trumps looks (I doubt you will feel great if you have poor vital signs). When we say biomarkers we typically refer to blood chemistry labs like lipid panels, hormones, etc. A number on a piece of paper that may or may not be connected to a future health event is rarely a better metric than one’s improved vitality