40 years ago people were born from thin parents, today they're born from obese parents. This has to have an effect on the genetic makeup of the children.
To be more precise: I know there are animal species that changed their natural colors to grey-ish tones nearby the cities in less than 100 years, but that seems to me more a result of selective breeding: the non-grey individuals were eaten/killed, so in a relatively short span only those with the grey gene survived. However, given that we are not killing those that are born without the obesity gene, there shouldn't be any reason for such change at a genetic level in such a short timespan at a big scale (unless the obese were over-breeding the non-obese by at least one order of magnitude, which is nonsense).
However, I think the article is saying, "In the long run, for whatever reason, statistically speaking, 95% of people revert to their high water mark of weight, nullifying their previous efforts at weight loss." This strikes me as utterly uncontroversial, aside from our widespread want to be among the 5%.
And my personal take: willpower can win battles, but our central tendencies usually win the war.
Mother obesity affects The brain and metabolism of the baby. This includes the way fat is managed. This is even before birth.