This is typically due to eating too much starch and junk food. The problem isn't caused by being poor, but rather is correlated with the same bad financial habits
The biggest problem is this: As soon as you're rich, everybody who's ever known you, or kinda known somebody who's known you, or is working for a good cause comes knocking to ask for a handout.
Read about the guy I was talking about. He bought a mansion, a million dollars worth of cars, a lear jet - all in the first year. He blew $12M in the first year. It had nothing to do with people hitting him up for cash - he blew it.