Getting yourself into shape is one thing, and it usually takes a lot of work. Keeping that weight off is a totally different process, and it means a lifestyle of constant attention to what you're putting into your body, and what you're doing to burn off excess energy and calories. This gentleman has managed to shed all the weight he was carrying in his 20s - and he's kept it off for a full twenty years. Would you believe that he's over 40 in the picture on the right?
When he was much younger he'd always played sports, but a late diagnosis of asthma killed off his dreams of becoming a professional sportsman, and so he lapsed into depression, preferring to stay at home with junk food than carry on with the limited exercise he was able to do. The change came when he found that he grew out of his asthma, and he was able to run again. Since then, he's never stopped.