If there's any patterning or imagery on the health bar you can use a 'Tiled Background' object.. and then just reduce the width. The image will be cropped.
If it's just a plain coloured bar, you can use a normal sprite and reduce the width in the same way. Just remember to set 'sampling' to 'point' in the project settings. (this gets rid of any blurry edges)keepee2012-10-23 19:40:02