A person with an injured back will gain weight because almost any form of exercise is impossible without a lot of pain, unless they go on a diet of lettuce in which case they will look thin but frail. Old people fall into this category, but also a mechanic who injures himself while working. I weigh a healthy 180 now, but when I had an injury I balooned up quickly, then years later when I found a way to treat my back, was back to normal weight in weeks. After that, I worked in an office, and some people played politics by going back as far as 10 years to keep circulating photos of me. One photo was of me trying to play guitar for my dieing Grandmother while I was in more pain that I even thought was possible..unstoppable and literally almost unbearable. I used to judge. I do not judge because I am no longer a child.