In the pink
Definition 1 of 2
Pro Tip 1/3Health Emphasis
Use it to emphasize excellent health, not just being okay or average. 
After adopting a healthy lifestyle, he's in the pink.
Pro Tip 2/3Positive Change
Often used to indicate recovery or improvement in health. 
She’s been in the pink since completing treatment.
Pro Tip 3/3Common Usage
Frequently appears with 'of health' for added emphasis on well-being. 
My grandparents are 80 and still in the pink of health!