A couple months ago, I went to the local recreation center with several kids for a swim party. Being the only adult, I stayed out and made sure none of our kids drowned - not fulling trusting the 16 year old lifeguard who was flirting with a girl instead of watching the water.
While there, another group of kids came in, with their parents and both sets of grandparents. With the adults were a couple extra guys, not sure if they were friends or relatives or what. Every single one of the adults must have topped 300, and a couple of the guys had to have been 400+.
While the kids were swimming, laughing, diving...the adults were clustered along the wall, snacking on various things from the vending machines. (That machine looked pretty empty when we left!)
I'm willing to bet that most of those people blame genetics for their weight, and never stop to think how different their lives would be if they were swimming instead of snacking.
That said, I do want to point out that the government changed the obesity tables several years ago. For my height, it used to be that I'd need to weigh like 240 or something to be considered obese. When they changed the table, it dropped to 185 or so. Now, I have never been skinny, (I was in really good shape in college at 135), but weighing 50 pounds more by my 50's shouldn't have made my weight a health issue. In fact, that was considered pretty normal for women with multiple kids - it used to be called "matronly." But now it's called "Obese."
Strangely enough, there have been multiple medical studies that concluded that obesity - actual obesity, not "middle-age spread" - is HELPFUL in surprising ways. For example, obese dialysis patients survive longer than thin patients. Obese people are also more likely to survive a heart attack.