III. ‘It’s Called Vanishing Caloric Density.’

At a symposium for nutrition scientists in Los Angeles on Feb. 15, 1985, a professor of pharmacology from Helsinki named Heikki Karppanen told the remarkable story of Finland’s effort to address its salt habit. In the late 1970s, the Finns were consuming huge amounts of sodium, eating on average more than two teaspoons of salt a day. As a result, the country had developed significant issues with high blood pressure, and men in the eastern part of Finland had the highest rate of fatal cardiovascular disease in the world. Research showed that this plague was not just a quirk of genetics or a result of a sedentary lifestyle — it was also owing to processed foods. So when Finnish authorities moved to address the problem, they went right after the manufacturers. (The Finnish response worked. Every grocery item that was heavy in salt would come to be marked prominently with the warning “High Salt Content.” By 2007, Finland’s per capita consumption of salt had dropped by a third, and this shift — along with improved medical care — was accompanied by a 75 percent to 80 percent decline in the number of deaths from strokes and heart disease.)

Karppanen’s presentation was met with applause, but one man in the crowd seemed particularly intrigued by the presentation, and as Karppanen left the stage, the man intercepted him and asked if they could talk more over dinner. Their conversation later that night was not at all what Karppanen was expecting. His host did indeed have an interest in salt, but from quite a different vantage point: the man’s name was Robert I-San Lin, and from 1974 to 1982, he worked as the chief scientist for Frito-Lay, the nearly $3-billion-a-year manufacturer of Lay’s, Doritos, Cheetos and Fritos.

Lin’s time at Frito-Lay coincided with the first attacks by nutrition advocates on salty foods and the first calls for federal regulators to reclassify salt as a “risky” food additive, which could have subjected it to severe controls. No company took this threat more seriously — or more personally — than Frito-Lay, Lin explained to Karppanen over their dinner. Three years after he left Frito-Lay, he was still anguished over his inability to effectively change the company’s recipes and practices.

By chance, I ran across a letter that Lin sent to Karppanen three weeks after that dinner, buried in some files to which I had gained access. Attached to the letter was a memo written when Lin was at Frito-Lay, which detailed some of the company’s efforts in defending salt. I tracked Lin down in Irvine, Calif., where we spent several days going through the internal company memos, strategy papers and handwritten notes he had kept. The documents were evidence of the concern that Lin had for consumers and of the company’s intent on using science not to address the health concerns but to thwart them. While at Frito-Lay, Lin and other company scientists spoke openly about the country’s excessive consumption of sodium and the fact that, as Lin said to me on more than one occasion, “people get addicted to salt.”

Not much had changed by 1986, except Frito-Lay found itself on a rare cold streak. The company had introduced a series of high-profile products that failed miserably. Toppels, a cracker with cheese topping; Stuffers, a shell with a variety of fillings; Rumbles, a bite-size granola snack — they all came and went in a blink, and the company took a $52 million hit. Around that time, the marketing team was joined by Dwight Riskey, an expert on cravings who had been a fellow at the Monell Chemical Senses Center in Philadelphia, where he was part of a team of scientists that found that people could beat their salt habits simply by refraining from salty foods long enough for their taste buds to return to a normal level of sensitivity. He had also done work on the bliss point, showing how a product’s allure is contextual, shaped partly by the other foods a person is eating, and that it changes as people age. This seemed to help explain why Frito-Lay was having so much trouble selling new snacks. The largest single block of customers, the baby boomers, had begun hitting middle age. According to the research, this suggested that their liking for salty snacks — both in the concentration of salt and how much they ate — would be tapering off. Along with the rest of the snack-food industry, Frito-Lay anticipated lower sales because of an aging population, and marketing plans were adjusted to focus even more intently on younger consumers.

Except that snack sales didn’t decline as everyone had projected, Frito-Lay’s doomed product launches notwithstanding. Poring over data one day in his home office, trying to understand just who was consuming all the snack food, Riskey realized that he and his colleagues had been misreading things all along. They had been measuring the snacking habits of different age groups and were seeing what they expected to see, that older consumers ate less than those in their 20s. But what they weren’t measuring, Riskey realized, is how those snacking habits of the boomers compared to themselves when they were in their 20s. When he called up a new set of sales data and performed what’s called a cohort study, following a single group over time, a far more encouraging picture — for Frito-Lay, anyway — emerged. The baby boomers were not eating fewer salty snacks as they aged. “In fact, as those people aged, their consumption of all those segments — the cookies, the crackers, the candy, the chips — was going up,” Riskey said. “They were not only eating what they ate when they were younger, they were eating more of it.” In fact, everyone in the country, on average, was eating more salty snacks than they used to. The rate of consumption was edging up about one-third of a pound every year, with the average intake of snacks like chips and cheese crackers pushing past 12 pounds a year.

Riskey had a theory about what caused this surge: Eating real meals had become a thing of the past. Baby boomers, especially, seemed to have greatly cut down on regular meals. They were skipping breakfast when they had early-morning meetings. They skipped lunch when they then needed to catch up on work because of those meetings. They skipped dinner when their kids stayed out late or grew up and moved out of the house. And when they skipped these meals, they replaced them with snacks. “We looked at this behavior, and said, ‘Oh, my gosh, people were skipping meals right and left,’ ” Riskey told me. “It was amazing.” This led to the next realization, that baby boomers did not represent “a category that is mature, with no growth. This is a category that has huge growth potential.”