Americans are back in the chips.

After years of battling health food enthusiasts and countless waves and flavors of Cheetos, Doritos and Nachos, the spud appears to be off the blacklist.

That's the word from Snaxpo '85, the annual convention of the Potato Chip-Snack Food Association. The Alexandria-based group, which monitors most things edible and crunchy, says that the nation's chip business has never been better.

"Americans like to chew," said John R. Cady, president of the association. "They like to crunch; they like to taste potato chips."

Sales figures for "chippers," as the industry calls them, support Cady's assertions. The salted snack food industry rang up record sales of $6.1 billion in 1983, up more than 15 percent from the previous year. Last year's figures have not been released, but Cady predicts a 23 percent jump in sales.

Although there are a variety of reasons for the renaissance of the chip, Cady says that on the truly weighty issues of the day -- sodium, cholesterol, fats and labeling -- the snack food establishment has much to boast about. Potato chips were among the first products labeled with nutritional information.

An average one-ounce serving of potato chips contains less than 10 grams of fat, almost no cholesterol and about as much salt as two slices of bread, according to the Department of Agriculture.

But even today, when fashionable candy shops sell chocolate-covered potato chips, and Yuppies in running shoes race to Bloomingdale's to buy barbecue sauce made specially for their ridged chips, spud skeptics continue to urge moderation.

"Of course, nothing is terrible if you only have a little of it," said Susan Welsh, a diet specialist for the Department of Agriculture's Human Nutrition Information Service. "But if you are looking to cut back on sodium and fat, then potato chips would be a great place to start."

Since 1853, when an American Indian chef named George Crum gave birth to them by accidentally slicing some french fries too thin, potato chips have had a relatively free ride with the American public.

But in the 1970s, "natural" foods began to capture the imagination of the nation. Fried foods got short shrift, bran became the order of the day, and the potato chip industry spent hundreds of thousands of dollars selling itself to a public that had given little thought to protein content.

"That was a tough time for the whole industry," said Cady, whose organization recently moved into a new office in Old Town Alexandria. "There were so many illusions about the evils of eating snack food."

So the industry began to nibble away at the myths. They hired consultants to help explain that the 4.5 pounds of chips that the typical American consumes each year really is only about a bag a week.

And they waged war on granola.

"Granola is just a marketing gem," said Ronald Deutsch, a nutrition adviser to the Potato Chip-Snack Food Association. "People think it's something special because it's 'natural,' but we are looking at a processed grain food with nuts and raisins."

But the broadsides on health foods may no longer be necessary. Recent research suggests that even the healthiest people prefer potato and corn chips to sweet snack foods.

Diane Wakat, a physiologist at the University of Virginia, surveyed the snack habits of adults enrolled in weight control centers across the country and found that 30 percent of them prefer chips to any other munchies. Candy came in a weak second, with 17 percent of the vote.

And since snacking is here to stay, chip manufacturers are working round the clock to remain competitive.

According to Cady, his 600 members are taking advantage of sophisticated new computer technology in an attempt to develop the perfect spud for slicing and frying.

And Americans apparently stand ready to eat them as never before. With sour cream, vinegar or salt, barbecued or plain, the chips are sliding out of vending machines in record numbers.

Even officials who disdain empty calories are giving the chip its due these days.

"Let's face it," said Isabel Wolf, administrator of the Human Nutrition Information Service. "It is a fact of life that not many people are going to relax by eating celery and carrot sticks."