Still, 93 percent of those with limited access to supermarkets do have access to vehicles, though it takes them 20 more minutes to travel to the store than the national average. And after a long day of work at one or even two jobs, 20 extra minutes — plus cooking time — must seem like an eternity.

Taking the long route to putting food on the table may not be easy, but for almost all Americans it remains a choice, and if you can drive to McDonald’s you can drive to Safeway. It’s cooking that’s the real challenge. (The real challenge is not “I’m too busy to cook.” In 2010 the average American, regardless of weekly earnings, watched no less than an hour and a half of television per day. The time is there.)

The core problem is that cooking is defined as work, and fast food is both a pleasure and a crutch. “People really are stressed out with all that they have to do, and they don’t want to cook,” says Julie Guthman, associate professor of community studies at the University of California, Santa Cruz, and author of the forthcoming “Weighing In: Obesity, Food Justice and the Limits of Capitalism.” “Their reaction is, ‘Let me enjoy what I want to eat, and stop telling me what to do.’ And it’s one of the few things that less well-off people have: they don’t have to cook.”

It’s not just about choice, however, and rational arguments go only so far, because money and access and time and skill are not the only considerations. The ubiquity, convenience and habit-forming appeal of hyperprocessed foods have largely drowned out the alternatives: there are five fast-food restaurants for every supermarket in the United States; in recent decades the adjusted for inflation price of fresh produce has increased by 40 percent while the price of soda and processed food has decreased by as much as 30 percent; and nearly inconceivable resources go into encouraging consumption in restaurants: fast-food companies spent $4.2 billion on marketing in 2009.

Furthermore, the engineering behind hyperprocessed food makes it virtually addictive. A 2009 study by the Scripps Research Institute indicates that overconsumption of fast food “triggers addiction-like neuroaddictive responses” in the brain, making it harder to trigger the release of dopamine. In other words the more fast food we eat, the more we need to give us pleasure; thus the report suggests that the same mechanisms underlie drug addiction and obesity.

This addiction to processed food is the result of decades of vision and hard work by the industry. For 50 years, says David A. Kessler, former commissioner of the Food and Drug Administration and author of “The End of Overeating,” companies strove to create food that was “energy-dense, highly stimulating, and went down easy. They put it on every street corner and made it mobile, and they made it socially acceptable to eat anytime and anyplace. They created a food carnival, and that’s where we live. And if you’re used to self-stimulation every 15 minutes, well, you can’t run into the kitchen to satisfy that urge.”