They say that physical recovery is a precursor to the mental recovery for a number of reasons. For starters the mind alone requires 5-600 calories daily to even function on it's own at full capacity. Consider that if your body is undernourished and restricted then your brain isn't even working at full capacity therefore your chemicals, the emotions, everything is imbalanced; you can't hope to "get better" mentally if your mind isn't even working to full capacity.
Secondly you have to HAVE a healthy body before it's healthy to learn to love it. That part is just common sense!