I was an athlete and did a lot of physical training most my life, which I thought was helping me. But it's the very, over exertion of my muscles and the corresponding joints that caused the wear, tear and eventual damage. Much of my arthritis is do to my strenuous exercising, according to my doctors. I asked them, what should I have done, and they said, less impact and more moderation. We thought "no pain, no gain" back then, but now they know better.
If you look at the statistics, professional athletes in general have more physical problems from overuse, less quality and shorter life spans. Even with arthritis, you need to do some movement but it varies, day to day and is extremely limited.
Of course much of this is situational and genetics, but I can't stress enough low impact, like swimming, yoga, Thai Chi, cycling and walking. Running, stepping, climbing, skiing, and any sports with contact are all very rough on you in old age. Even golfing can be hazardous, if you're an intense player.
Maybe I've got the wrong mental picture of what could be considered obese. He doesn't look warm and cuddly to me either - more like a policeman or someone who works in construction, who doesn't want any :bs: 
