Niche eaters are nitpickers. Sometimes they care, sometimes they don't. Some things they'll eat, some things they won't.

Overwhelmed by a dizzying array of information about nutrition and food safety, consumers are picking their causes. Their niche established, they eliminate some foods and retain others, resulting in strange and inconsistent combinations:

Katherine Tallmadge, a local consulting dietitian, recalls a client who wouldn't eat fruit unless it was ugly. The man reasoned that an unattractive exterior meant the fruit didn't contain as many pesticide residues; nonetheless, he would scour the produce with a pot scrubber and wash it, filling and draining the sink three or four times. Although he was concerned about chemicals, his diet was soaring in fat; he regularly ate pie for breakfast and fast food burgers for lunch or dinner.

Claudia Telliho, who works at the Smithsonian, says her father, about 30 pounds overweight, has two or three helpings of everything at dinner, coffee and cake or cookies for dessert and ice cream as a late night snack. But, alongside his generously filled dinner plate is a plateful of eight or 10 vitamins. "It came along with the general men's mid-life crisis," said Telliho, of her father's supplement regimen. Shoppers have "different philosophies which don't have a rational consistency," said Brad Eisold, manager of Hugo's Natural Foods Market, which sells organic licorice teddy bears. Eisold has seen people who are concerned about pesticides in vegetables but not hormones in meat; vegetarians who purchase lots of chips and cookies while avoiding meat, and animal rights activists who will buy only dolphin-safe tuna for themselves but don't care about the tuna they feed their cats.

The notion that we do not eat consistently is not illogical, said Peter Sandman, director of the Environmental Communication Research Program at Rutgers University. What's more important is being consistent in our inconsistency. "That's more highly valued than making sense," he said.

"There's no question that we could protect ourselves better if we backed off our habits and prejudices and rethought everything from scratch. But nobody does that," he said.

Some observers of niche eating subscribe to the theory that it may be the result of an ever-increasing amount of confusing information. People "grab a little piece here and a little piece there and they try to put it together, only sometimes it doesn't compute," said Johanna Roth, a consulting nutritionist and health counselor in Bethesda.

Or, it's a function of being able to worry about just a few things at a time. "Everyone has a worry agenda," said Sandman, "and it's crowded. To get something onto your worry agenda, you have to kick something off. It's like a messy desk; you read a news story that 'peanuts are dangerous.' For the moment, that's what's on the top of your desk. Then it gets covered over."

Some nutritionists believe that people find it easier to worry about single issues, rather than the whole picture. "People get hooked on one gimmick and they have tunnel vision. Often they lose the whole meaning of what eating healthy is about," said Ann Litt, a local consulting nutritionist.

Litt said there are parents who assiduously restrict their children's sugar intake but don't think twice about giving them hot dogs. Then there are those who are driven by the "lite": for lunch, they pack their children lite ham on lite bread with a diet soda and lite Hostess cupcakes. But they would be much better off making real dietary changes, such as including fresh fruits or vegetables or whole grain bread, she said, and serving lean protein sources for dinner (chicken breasts instead of chicken nuggets, broiled fish instead of fish sticks, lean red meats instead of hamburger).

What drives Tallmadge "nuts" are people who purchase packaged foods such as potato chips or cookies only if they are organic or "natural," even though they are high in fat. "I see fat as the major problem," Tallmadge says. "Once people get the fat out of their diets, then they can worry about all those other things."

Litt agrees, but blames food advertisers. "So many people believe that if it says 'no cholesterol' and 'natural' that potato chips are OK. I think advertising has really done a lot to mislead people."

But Sandman believes that people worry more about pesticides and chemical additives than fat because "it feels better." In the case of chemicals, "there's a villain. It allies you with a political cause. You can't make friends by talking about how you're a fat slob," Sandman said. It's much more socially and psychologically appealing to talk about "the damn chemical companies poisoning us all," he concluded.

While these dietary patterns may be a response to juggling competing information, sometimes they may stem simply from a lack of information, or an inappropriate interpretation of it.

Tallmadge remembers an investment banker with very high cholesterol who was referred to her by a local doctor. The woman's cholesterol would not budge despite her gallant dietary efforts. The banker "had convinced the doctor that she had read everything and knew everything. All she was eating was chicken and fish," recalled Tallmadge.

So Tallmadge asked the woman to keep a diary of what she ate for a few days. What Tallmadge discovered was that "literally all she was eating was chicken and fish. No vegetables, no starches, no nothing except chicken and fish." Thus, even though the meats she was eating were lean, the percentage of fat in her diet was still high because it was not being offset by any other foods.

There are dietary issues with which people are ignorant, Sandman conceded. But more frequently, "it's not that people don't get it. They don't want to obey it," he said. "If they are eating a lot of crap, it's not because they're ill-informed. It's because they want to eat crap."

Then there are those who tout their dietary proclivities without really obeying them. Eisold of Hugo's market is always surprised by shoppers who call themselves vegetarians even though they eat poultry and fish, or those who are vegetarians "once or twice a week."

A shopper at Hugo's last week, Diane Olsen, said she usually eats a typical American junk food diet, but that for the past month she has been following a macrobiotic one. She said she had been getting headaches because she had neglected her macrobiotic diet for three days, so she was back buying organic vegetables. But she admitted that she'd probably continue to go "back and forth" between her junk food diet and her macrobiotic one as she "adjusted."

Classic and extremely prevalent examples of dietary inconsistency are putting artificial sweetener in coffee with a second helping of cheesecake, or drinking diet soda with an industrial-sized box of chocolate mints.

"There's just so much guilt about what we eat now," said Carole Hoage, a clinical psychologist in the District who specializes in eating disorders. "We should all be eating low-fat, healthy diets. It's very hard to eat perfectly." Combining contradictory foods "is a way to bring down that guilt," she said. The rationalization, Hoage said, is, "I'm not totally guilty. I don't eat meat, so it's OK if I eat three bags of Doritos."

For many people, however, it's simply a question of making trade-offs. "Eating sugared soda feels like a completely unnecessary consumption of calories," said Sandman. "I don't get any pleasure or benefit out of it. That's not irrational. It costs me nothing in the quality of my life to drink a Diet Coke," he said. "But I suffer if I give up ice cream."