Alot of things have been mentioned but none of it is about obesity (There probably is a thread somewhere about it, I haven't checked every page).
But now in the UK about 46% of men in England and 32% of women are overweight (their body mass being about 25-30 kg) and 17% of men and 21% of women are obese (body mass of over 30 kg). And around 13% of 8 year olds and 17% of 15 year olds in England were obese.
In the USA about 34 percent of U.S. adults age 20 and older are overweight, and about 30 percent or 59 million people are obese. Also 15 percent of children age 6 to 19 are overweight, about triple the proportion 20 years ago.
(Please inform me if any of my statistics are wrong).