In the largest study ever done on obesity and mortality, researchers reported findings last week that made clear the link between being overweight and early death.

The study, conducted by the American Cancer Society and published last week in the New England Journal of Medicine, is astonishing in size and scope — more than 1 million people, from young adults to the elderly, from healthy and trim non-smokers to those with dangerous pre-existing conditions, were followed for 14 years. More than 200,000 died during that period. Deaths from heart disease and cancer — the two leading causes of death — tracked being overweight step-for-step: the slightly overweight had slightly increased death rates; the moderately overweight (say, 20 to 30 pounds over) had death rates 50 to 100 percent higher; the severely overweight had death rates up to 300 percent higher.

These findings come at a time when more and more Americans, an estimated 55 percent, are overweight. They also come at a time when the soaring cost of health care (heart disease and cancer being especially expensive to treat) is putting insurance beyond the reach of many. While some people — experts say about 3 percent — are overweight due to genetic disposition or other medical conditions, for the vast majority it is simply too much of the wrong food and too little exercise.

Several medical professionals commenting on the study have made this very good point — the answer is not regulation, not Big Tobacco-style litigation, but education for consumers, the food industry, insurance companies, employers, urban planners, even real-estate developers. Dr. JoAnn Manson, a Harvard University endocrinologist and preventative-health specialist, called for “a coordinated campaign to turn this around, at the community level, at the environmental level, with changes in the food industry and marketing industry, having more bike paths and sidewalks.”

This study is important for several reasons. It helps put the true price tag on that bacon cheeseburger. It makes the connection between poverty, poor diet and disease clearer than ever. And it elevates being overweight and out-of-shape from just another lifestyle choice to a genuine public-health issue, with real and unacceptible costs in human life, debilitating disease and the use of scarce and increasingly expensive medical resources.