Are there any medical risks or disadvantages of being so heavy that you have to lean back at all times to keep from falling forward?

While out having a coffee I seen a person who was so big she literally had to lean backwards to keep her front from pulling her forward off balance, to not lean back she had to take some weird stance as if readying for martial arts. To be so big that you have to literally lean back all the time to maintain your balance, is that bad for the back, hips, neck, etc. if not immediately but over many years?