It stands to reason that if you know you’re overweight or obese, and you know your extra pounds are unhealthy, that you’ve made a stab at losing weight. Right?

Not so much anymore, new research shows.

The proportion of American adults who were either overweight or obese has been growing steadily for decades, rising from about 53% a generation ago to roughly 66% more recently. (emphasis added)

But the share of these adults who had gone on a diet dropped during the same period, researchers reported Tuesday in the Journal of the American Medical Assn.

The study relied on data from the National Health and Nutrition Examination Survey, an ongoing project of the Centers for Disease Control and Prevention.

In the first survey period, between 1988 and 1994, about 56% of overweight or obese adults reported they had tried to lose weight in the last year. By the last survey period, between 2009 and 2014, the proportion of overweight or obese respondents reporting recent weight-loss attempts had declined to about 49%.

That trend […]