The following editorial appeared recently in the Pittsburgh Post-Gazette.

Not only is Earth getting warmer, but the humans who walk upon it are getting heavier. In the latter phenomenon, however, there is little debate as to the cause. It’s a man-made global health crisis.

A new study led by British scientists, undertaken with the World Health Organization and 700 researchers worldwide, has some grim news: About 640 million adults are obese, up from 105 million in 1975. At this rate, about 20 percent of the adult population will be obese by 2025. While China is coming on strong, the United States maintains its status as being home to the highest number of severely obese men and women in the world.

Among the many factors at play, the main culprit is food — bad and relatively cheap food. Over the 40 years charted by the study, many countries have risen out of poverty. The citizens turn to high-calorie and processed foods in abundance, not more fruits, vegetables, whole grains and free-range chicken raised without antibiotics. The resulting obesity is “too extensive to be tackled with medications … or a few extra bike lanes,” said Majid Ezzati, the study’s senior author. “We need coordinated global initiatives.”

Personal choices made by members of an affluent society are part of the problem. Makers of public policy, however, cannot mandate CrossFit memberships and portion control. The focus should be on the international food industry, as examined by authors such as Michael Moss (“Salt Sugar Fat: How the Food Giants Hooked Us”) and former Food and Drug Administration director David Kessler, whose “The End of Overeating” laid bare the strategy of corporations that “design food for irresistibility” on a mass scale — akin to tobacco companies manipulating nicotine content.

The study notes that amid the plenty, many people around the world suffer from hunger and low body weight. Yet the study’s main finding shows that the trend lines have crossed: Global health is now more endangered by people who are overweight than underweight.