I'm not sure why anon is making a big deal out of that. One time when I was on a second date, the woman told me that I seemed like quite a pessimist. I said "No, if I were a pessimist, I would never stop screaming." She didn't want to see me again but I still chuckle whenever I remember it.
Just because OOP is American doesn't mean that "most people" are Americans... The US is about 4% of the global population. "Most people" is always global since you're referring to everyone on the planet, you could say "most people there get fat" though.
Pregnancy and childbirth are quite hard on the body, it's one of the reasons it should be her choice whether to endure it. Of course, strict religions often don't allow her to choose anything else. Apparently her husband chose to default on his vows, though.
Raising an infant into a child and then an adolescent and hopefully an adult is also quite hard and ages a person considerably. It puts a strain on finances, especially as a single parent, such that cheap carbs are often chosen over more expensive fresh vegetables.
Got fat, 2 kids, no husband does sound like a doozy. It's not a direction many would like their life to go I'd imagine and it has to make dating a real bitch.