It’s all part of Frito-Lay’s attempt to secure its financial future by creating the ultimate oxymoron: healthy junk food. At a time when rising obesity levels have become a national preoccupation and New York City has banned artery-clogging trans-fatty oils in restaurants, food companies are trying to adapt to shifting nutritional mores. It’s a risky and expensive balancing act—no company wants to alienate the junkies who care about taste above all. But, in fits and starts, food companies are changing. McDonald’s has become the nation’s biggest buyer of apples (which it serves with a side of sugary caramel sauce). Coca-Cola recently launched Diet Coke Plus, fortified with vitamins. After several years and 28 recipes, all 4,500 Dunkin’ Donuts stores will be using zero-gram trans-fat oil to make the doughnuts. But will Homer Simpson still approve?

Perhaps no company has more at stake than chip-giant Frito-Lay, the world’s biggest producer of snack foods, with $10 billion-plus in annual sales. Home of Doritos, Fritos, Cheetos and Tostitos, Frito-Lay represents 36 percent of parent company PepsiCo’s operating profits. Faced with emerging scientific data of the perils of trans fats, which are created when hydrogen is added to liquid oil in a process that creates a solid fat that’s easier to work with, Frito-Lay abandoned their use in 2002. But now that so many other food companies have made the switch, how can FritoLay still look more healthful than the competition?

The snack company has come up with a provocative new tack: making chips it claims provide the kind of dietary fat a body needs (seriously). Often, companies replace trans fats with saturated fats, which are known to raise LDL, or “bad,” cholesterol. So Frito-Lay is starting to use more unsaturated fats, which help lower LDL cholesterol and are believed to raise HDL, or “good,” cholesterol. “We’re telling customers that it may seem counterintuitive, but there are good fats, and the fat you are going to get in our products is going to be beneficial,” says Bob Brown, Frito-Lay’s director of nutrition and regulatory affairs. It’s not the easiest argument to make—no company has yet developed a chip as nutritionally sound as, say, carrot sticks or a few raw nuts.

Frito-Lay’s conversion last year to sunflower oil, however, demonstrates the complexity of addressing consumer awareness about nutrition on such a large scale. When the company first eliminated trans fats, it switched to cottonseed oil, which, although healthier in some respects, was still high in saturated fat. Amid mounting evidence of a link between saturated fat and heart disease, Brown said the company knew it would need to evolve further, but its choices were limited: soybean oil, which spoils easily, or sunflower oil, of which there was little supply.

It took several years and millions of dollars for Frito-Lay, oilmakers and farmers to develop a sustainable sunflower crop. It was only last year that the supply was steady enough to make the switch—“eliminating 60 million pounds of saturated fat from the U.S. diet,” the company crowed. Frito-Lay’s research division is now looking for the next competitive advantage, from using more whole grains to adding colon-healthy fiber and lycopene, an antioxidant found in tomatoes and watermelon.

Not that Frito-Lay’s core customer cares deeply about heart-healthy eating habits. And, good fats or not, dietitians don’t plan on blessing high-calorie processed snacks any time soon. “Nobody got heart disease from a deficiency of chips,” says Lisa Young, a dietitian at New York University. “I think the food industry gets an A in marketing. But this is better than nothing.” As the saying goes (sort of): all that, and a bag of trans-fat-free, good-cholesterol-enhancing chips.