Take 15 minutes daily, thinking of pleasant scenarios regarding your body, with the sole intent of enjoying your body and appreciating its strength and stamina and flexibility and beauty. When you visualize for the joy of visualizing rather than with the intention of correcting some deficiency, your thoughts are more pure and, therefore, more powerful. When you visualize to overcome something that is wrong, your thoughts are diluted with the "lackful" side of the equation. In time, your physical condition will acquiesce to your dominant thoughts.