It's one thing for young people not to take care of themselves —they have time, a resilient body, and a lot more flourishing friends and relatives than older people do on their side. They believe they can and will get around to it someday. But older people...hmmm. Older people are a real curiosity.
The same individuals who wouldn't dream of letting the roof sag or the foundation crumble in their home, or who would be mortified to be seen driving to town in a disintegrating junker, determinedly maneuver their giant asses and jiggly man-boobs around in public with no shame at all. They have already lost a large percentage of their muscle mass —7% per decade since age 30— which used to give them a human form, burn fat effortlessly, and house their immune system. They've lost up to 70% of their deep lung capacity due to lack of aerobic exercise and smoking. Their bone mass has diminished to such a degree that when they fall due to the muscle loss and fat gain, they break their bones because their very structure has been so compromised.
Who in their right mind accelerates their deterioration intentionally by shunning exercise and embracing gluttony at a time in their life when they can least cope?
The correct answer is, nobody.