The power that salt holds over processed foods can be seen in an American snack icon, the Cheez-It.

At the company’s laboratories in Battle Creek, Mich., a Kellogg vice president and food scientist, John Kepplinger, ticked off the ways salt makes its little square cracker work.

Salt sprinkled on top gives the tongue a quick buzz. More salt in the cheese adds crunch. Still more in the dough blocks the tang that develops during fermentation. In all, a generous cup of Cheez-Its delivers one-third of the daily amount of sodium recommended for most Americans.

As a demonstration, Kellogg prepared some of its biggest sellers with most of the salt removed. The Cheez-It fell apart in surprising ways. The golden yellow hue faded. The crackers became sticky when chewed, and the mash packed onto the teeth. The taste was not merely bland but medicinal.

“I really get the bitter on that,” the company’s spokeswoman, J. Adaire Putnam, said with a wince as she watched Mr. Kepplinger struggle to swallow.

They moved on to Corn Flakes. Without salt the cereal tasted metallic. The Eggo waffles evoked stale straw. The butter flavor in the Keebler Light Buttery Crackers, which have no actual butter, simply disappeared.

“Salt really changes the way that your tongue will taste the product,” Mr. Kepplinger said. “You make one little change and something that was a complementary flavor now starts to stand out and become objectionable.”