The real reason being overweight is bad for your health:

[laundry_queen]

25. A lot of that is overuse injuries

from the current push for competitive sports in younger and younger kids. I'm in university (as a mature student) and the kids in my class that are right out of high school...so many of them are having multiple knee surgeries it's crazy. All from competitive sports.

I think obesity is more likely a result of painful joints and not the cause of them.

My dad is slim and has been all of his life, except for a few years right after he met my mom. he's always been super athletic. He played hockey for years, mostly as a goalie. Because goalies were always in high demand, he played nearly 5 days a week for many years, from the time he was 18. He also was fanatical about playing baseball. All of those butterfly stops and slides into home plate resulted in a need for a hip replacement at age 55.

I'm obese. I wasn't always obese though. I was extremely athletic as a teen. My knees completely wore out. I ended up with a disease in one knee and messed up ligaments in the other. I never did get surgery because it didn't exist back then. As I got older, it became more difficult to be athletic, because my knees were so insanely messed up. So, I gained weight. I also developed hip problems at age 16 when I was thin. I'm sure at some point I'll need a hip replacement.

My brother, also very athletic, has also dealt with serious overuse injuries that necessitated surgery. He has had multiple shoulder surgeries from being body checked in hockey along with being a baseball pitcher for years. He also has knee and hip issues.

None of my grandparents needed joint replacement surgery and they were all long-lived (1 grandmother made it to 85, 2 grandfathers made it to 97 and 102, 1 grandmother still alive and active at age 88). 2 were obese, 2 were not. None of them participated in sports. The only exercise they got was working on the farm (intense work, but not at the level of a competitive sport).