Whether you're dealing with weight issues or illness, correct use of visualization will put you in the mind frame to attract the results you desire.
What then is the correct use of visualization to overcome health or weight issues?
Do the opposite of what you've been doing. How have you been visualizing your body? You might say, "Well, up until now I haven't been visualizing anything?" That may not be entirely true. You just may not have been aware of it. What image have you been seeing in your imagination when you think about your body? As you seeing illness? Are you seeing a healthy weight?
Now you can reverse the process and do it consciously instead of unconsciously as you've been doing before.
Shift your mental image to pictures of health and wholeness, to an image of your ideal weight. And as you add the elements of empowerment of belief, emotional connection, own your image and become one with your image, your body will begin to respond to match the visual image of health and your ideal weight that you've programmed into the subconscious mind.
Like your thoughts, visualization also has a rate of vibration that attracts what is needed for its manifestation in your outer reality. You're doing the work from the inside of you which will produce the results outwardly instead of the other way around - working hard outwardly and against your internal programming.
Where does change begin? Within. Therefore using visualization to aid in the change process begins with the image you're allowing to become embedded within your subconscious mind which, like your thoughts when nurtured, will continue to grow and expand in your life.