Insert "Back off man, I'm a scientist" meme here.

I wonder if they corrected for spouse's body weight? Also if the children are overweight, and it's related to the parents, how much of it is due to the diet growing up?

Even if you buy the premise, what's been implicated? The dangers of weight gain--or are there genetic makeups that predispose to disease, and also to obesity?

The only real number the article gives us is that there are 60000 subjects. This is the weakness of this sort of study that poses as a strength. "We need bigger studies" is a criticism I see sometimes of smaller interventional studies, sometimes rightly so, but sometimes cause and effect is so obvious a tiny sample will do. Pancreas-free dogs not wasting away when you inject them with insulin. We don't need bigger studies, we need to find causes of disease that are clear enough that it doesn't take 60000 subjects to reach statistical significance.

This whole obesity-disease connection--there are people who are obese and apparently healthy. There are people who are sick and obese, where it seems very likely that the two are related--take a type II diabetic whose diabetes is either reversed or put into remission, or at least improved, whatever you want to call it, whether by bariatric surgery or by some purely dietary intervention. It's fairly rigorous that once adipose tissue is overloaded with fat, bad things happen. Lean tissue can develop fatty deposits, contributing to insulin resistance and diabetes. This happens at different body weights for different people. Obesity can be protective in one sense, in that one person might have to gain a lot more weight before developing diabetes than another, while at the same time, in the individual, getting fatter means getting closer to the point where fat cells are overloaded and inflamed and the liver etc. are becoming fatty.