You need much much more than a good diet and exercise. In fact, too much exercise can make you worse.
My refusing to stop playing tennis and racquetball is one of the reasons I kept getting worse. Gentle exercise is fine. But working up a major sweat is not a great idea until you are very far along in your recovery.
Exercise should be limited to walks and yoga for most people on this forum.
Diet alone will not do it since our foods are so deficient in nutrients now. I posted a study a couple of weeks ago that compare the nutrients in an apple from from 1914 and 1992 (almost 20 years ago). Magnesium dropped 83%.
You need good quality supplements.
Also very important is to learn what triggers your sympathetic nervous system and how you can calm it down....meditation, mindfulness, slow breathing, make an effort to move in slow motion in everything you do.
You basically need to change the way you behave, think, your emotions, etc.....forever. We need to put our Type-A personality behaviors behind us.
People seem to be having success with things like the Gupta Amlygdala retraining and Healing Codes. They seem to help alot with calming the mind.
But yes, recovery is possible. There are several success stories on this forum. I have recovered in many many ways. Now, all of the damage from years of being stuck in fight or flight is not completely healed and some may never be. But I have no anxiety, I sleep through the night, my mind is not racing all the time, I don't get tired during the day, no brain fog, no mid afternoon crashes, better mood.
It will take a while to reverse the Osteopinia from years of mineral loss...but I definitely getting better.