If we want to have a 'sunny', optimistic disposition, to stop living on our nerves, and to let go of all the tension, anxiety, fear and repressed anger we're carrying around in our stomachs, we have to start developing our ability to see God more in our lives.
If we truly feel like we're standing before God all time, and that we have to account to Him for every thought, word and deed we do, then it gets much, much harder to tell lies about what we're doing and saying, and its impact on ourselves, and on others.
Of course, this isn't going to happen overnight, particularly when we have so much of our self-esteem and ego riding on keeping up appearances.
The real changes will start to occur, as always, when we get God involved in the process, and ask Him to start helping us to like ourselves and accept ourselves more. The truth - the real truth - is that God made us with our flaws and our problems and our evil inclinations, and that we don't have to get so hung-up about the choices that we make.
Our ego (also located in this area) wants us to believe that we're in charge of the world, and we're responsible for everything, and that God is out of the picture. (This is a particularly Western mindset, and a key reason why physically, so many people have so many issues in this area, particularly with their digestion and weight.)
The more we 'let go' of us, and our egos, and the more we try to acknowledge the truth, namely that God created us, flaws n'all, and God is really running the show, the easier we'll find it to accept ourselves, and also to accept God's will for our lives.
This is the fastest way of getting the Divine energy in this area to start moving.