There is also garlic powder, which has the powerful savory flavor known as umami. The “long hang time” of flavors like garlic creates a lingering smell that stimulates memories (and contributes to “Dorito breath”).

COTTON CANDY

CHEETOS PUFFS

POPCORN

Other foods that exhibit “vanishing caloric density”

Coca-Cola has a flavor that is similarly ambiguous and forgettable.

Despite the powerful tastes in Nacho Cheese, the Doritos formula balances them so well that no single flavor lingers in the mind after you’ve eaten a chip. This avoids what food scientists call “sensory specific satiety,” or the feeling of fullness caused by a dominant flavor. Would you eat a whole bag of rosemary chips? With Doritos, you go back for more.

Two acids, lactic and citric, get the saliva flowing, which triggers the impulse to eat. Another ingredient, buttermilk, delivers even more lactic acid.

Licking the dust from the fingers in its pure form, without the chip to dilute the impact, sends an even larger flavor burst to the brain.

A 1.75-ounce bag contains nearly a quarter of the daily maximum sodium intake recommended for most adults by the federal government.

The white dots on a wedge of Romano are concentrations of amino acids, which convey a brothy flavor.

By itself, monosodium glutamate has little taste. But when we tried this white powder mixed with salt, we could almost feel our brains start to sizzle. Despite complaints that it has side effects, MSG is still widely used in processed foods because it powers up other flavors, especially savory ones. Nacho Cheese chips also have two ingredients that crank up the flavor even more: derivatives from the nucleotide family called disodium inosinate and disodium guanylate. When we tasted this pair along with MSG and salt, Mr. Witherly tossed back his head and cried, “Wow! Oooh! Water!”

Mr. Witherly says that to maximize the pleasure in snacks, the goal is to deliver half the calories through fat, and Nacho Cheese Doritos hit this mark precisely. Scientists say fat is experienced not as a basic taste like sweetness or bitterness, but rather as a sensation, with a mouth feel that has all the power of sugar or salt. Fat in food is detected by the trigeminal nerve, which conveys the signal straight to the brain’s pleasure center.

When fat-laden snacks melt in the mouth, the brain thinks that the calories have disappeared, too, in what food scientists call “vanishing caloric density.” This tends to delay the feeling of fullness.

The blend of ingredients in Nacho Cheese is given one of the finest grinds in food processing: flour grinding, which creates a powder that fills every nook and cranny on the chip. This maximizes the amount that will contact saliva. Intentional or not, one byproduct is the powder left on your fingers.

Research has shown that consumers are attracted to bright colors. Doritos have three artificial colorings: two different yellows and a red.

Frito-Lay goes first class here with domestic Romano cheese, an expensive ingredient you won’t find in many other brands. (The company even refrains from using preservatives in many of its chips.) Romano is packed with its own taste enhancers.