I'm just digging my way out of this myself.
How did I get back in it? basically, I had to shake myself by the shoulders and slap myself across the face and tell myself to snap out of it.
I started reading, watching, living and breathing fitness and health again, just like I did in the beginning. I read books, articles, magazines, websites about healthy living. I watch documentaries about the damage fast food and junk food can do to your body/mind/psyche. I listen to things that are encouraging. I have immersed myself in the culture of health. For me when I surround myself with that I can't go off track. It might be a little bit brainwashing too